## 1. Project Overview & Quickstart (golang/vscode-go)

## File: README.md

# Go for Visual Studio Code

[](https://gophers.slack.com/messages/vscode/)



[The VS Code Go extension](https://marketplace.visualstudio.com/items?itemName=golang.go)
provides rich language support for the
[Go programming language](https://go.dev/).

## Requirements

* Visual Studio Code 1.90 or newer (or editors compatible with VS Code 1.90+ APIs)
* Go 1.21 or newer.

## Quick Start

Welcome! 👋🏻
Whether you are new to Go or an experienced Go developer, we hope this
extension fits your needs and enhances your development experience.

1.  Install [Go](https://go.dev) 1.21 or newer if you haven't already.

1.  Install the [VS Code Go extension].

1.  Open any Go file or go.mod file to automatically activate the extension. The
    [Go status bar](https://github.com/golang/vscode-go/wiki/ui) appears in the
    bottom right corner of the window and displays your Go version.

1.  The extension depends on `go`, `gopls` (the Go language server), and optional
    tools depending on your settings. If `gopls` is missing, the extension will
    try to install it. The :zap: sign next to the Go version indicates
    the language server is running, and you are ready to go.



You are ready to Go :-)    🎉🎉🎉

## What's next

* Explore more [features][full feature breakdown] of the VS Code Go extension.
* View the
  [settings documentation](https://github.com/golang/vscode-go/wiki/settings)
	and [advanced topics](https://github.com/golang/vscode-go/wiki/advanced) to
	customize the extension.
* View the [tools documentation](https://github.com/golang/vscode-go/wiki/tools)
  for a complete list of tools the VS Code Go extension depends on. You can
  install additional tools and update them by using "Go: Install/Update Tools".
* Solve issues with the
  [general troubleshooting](https://github.com/golang/vscode-go/wiki/troubleshooting)
	and [debugging troubleshooting](https://github.com/golang/vscode-go/wiki/debugging#troubleshooting)
	guides.
* [file an issue](https://github.com/golang/vscode-go/issues/new/choose) for
  problems with the extension.
* Start a [GitHub discussion](https://github.com/golang/vscode-go/discussions)
  or get help on [Stack Overflow].
* Explore Go language resources on [go.dev/learn](https://go.dev/learn) and
  [golang.org/help](https://golang.org/help).

If you are new to Go, [this article](https://golang.org/doc/code.html) provides
the overview on Go code organization and basic `go` commands. Watch ["Getting
started with VS Code Go"] for an explanation of how to build your first Go
application using VS Code Go.

## Feature highlights

* [IntelliSense] - Results appear for symbols as you type.
* [Code navigation] - Jump to or peek at a symbol's declaration.
* [Code editing] - Support for saved snippets, formatting and code organization,
  and automatic organization of imports.
* [Diagnostics] -  Build, vet, and lint errors shown as you type or on save.
* Enhanced support for [testing] and [debugging]

See the [full feature breakdown] for more details.




*(Code completion and Signature Help)*


In addition to integrated editing features, the extension provides several
commands for working with Go files. You can access any of these by opening the
Command Palette (`Ctrl+Shift+P` on Linux/Windows and `Cmd+Shift+P` on Mac), and
then typing in the command name. See the
[full list of commands](https://github.com/golang/vscode-go/wiki/commands#detailed-list) provided by this
extension.



*(Toggle Test File)*

**⚠️ Note**: the default syntax highlighting for Go files is provided by a
[TextMate rule](https://github.com/worlpaker/go-syntax) embedded in VS
Code, not by this extension.

For better syntax highlighting, we recommend enabling
[semantic highlighting](https://code.visualstudio.com/api/language-extensions/semantic-highlight-guide)
by turning on [Gopls' `ui.semanticTokens` setting](https://github.com/golang/vscode-go/wiki/settings#uisemantictokens).
    ```
    "gopls": { "ui.semanticTokens": true }
    ```

## Setting up your workspace

The VS Code Go extension supports both `GOPATH` and Go modules modes.

[Go modules](https://golang.org/ref/mod) are used to manage dependencies in
recent versions of Go. Modules replace the `GOPATH`-based approach to specifying
which source files are used in a given build, and they are the default build
mode in go1.16+. We highly recommend Go development in module mode. If you are
working on existing projects, please consider migrating to modules.

Unlike the traditional `GOPATH` mode, module mode does not require the workspace
to be located under `GOPATH` nor to use a specific structure. A module is
defined by a directory tree of Go source files with a `go.mod` file in the
tree's root directory.

Your project may involve one or more modules. If you are working with multiple
modules or uncommon project layouts, you will need to configure your workspace
by using [Workspace Folders]. See the
[Supported workspace layouts documentation] for more information.

## Pre-release version

If you'd like to get early access to new features and bug fixes, you can use the
pre-release extension. Following the vscode's [convention](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#prerelease-extensions),
we use the minor version of the extension version number to distinguish stable
and pre-release versions (`0.ODD_NUMBER.patch` for pre-release, `0.EVEN_NUMBER.patch`
for stable release).

To install the pre-release version, use the drop-down list
to select "Install Pre-Release Version", or if already installed the Go extension,
use the "Switch to Pre-Release Version" option in the Visual Studio Code
extension management page. For more details about this mechanism, see the
[Visual Studio Code's documentation](https://code.visualstudio.com/updates/v1_63#_pre-release-extensions).

## Telemetry

VS Code Go extension relies on the [Go Telemetry](https://go.dev/doc/telemetry) to
learn insights about the performance and stability of the extension and the
language server (`gopls`).
**Go Telemetry data uploading is disabled by default** and can be enabled
with the following command:

```
go run golang.org/x/telemetry/cmd/gotelemetry@latest on
```

After telemetry is enabled, the language server will upload metrics and stack
traces to [telemetry.go.dev](https://telemetry.go.dev). You can inspect what
data is collected and can be uploaded by running:

```
go run golang.org/x/telemetry/cmd/gotelemetry@latest view
```

If we get enough adoption, this data can significantly advance the pace of
the Go extension development, and help us meet a higher standard
of reliability. For example:

- Even with [semi-automated crash
  reports](https://github.com/golang/vscode-go/issues?q=is%3Aissue+is%3Aopen+label%3AautomatedReport)
  in VS Code, we've seen several crashers go unreported for weeks or months.
- Even with [a suite of
  benchmarks](https://perf.golang.org/dashboard/?benchmark=all&repository=tools&branch=release-branch.go1.20),
  some performance regressions don't show up in our benchmark environment (such
  as the [completion bug](https://go.dev/issue/62665) mentioned below!).
- Even with [lots of great
  ideas](https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+label%3Agopls+label%3Afeaturerequest)
  for how to improve gopls, we have limited resources. Telemetry can help us
  identify which new features are most important, and which existing features
  aren't being used or aren't working well.

These are just a few ways that telemetry can improve gopls. The [telemetry blog
post series](https://research.swtch.com/telemetry-uses) contains many more.

Go telemetry is designed to be transparent and privacy-preserving. Learn more at
[https://go.dev/doc/telemetry](https://go.dev/doc/telemetry).

## Support Policy

The Go extension is maintained by engineers on the
[Go tools team](https://github.com/orgs/golang/teams/tools-team/members),
who actively monitor the [VS Code Go](https://github.com/golang/vscode-go/issues)
and the [Go](https://github.com/golang/go/issues?q=is%3Aissue+is%3Aopen+label%3Agopls)
issue trackers.

We support only the latest stable and pre-release versions of the extension.

### Supported Go and tools

The Go extension follows the [Go Release Policy](https://go.dev/doc/devel/release.html#policy),
meaning that it _officially_ supports the two most recent major Go releases.
The Go team maintains _best-effort_ support for the last three major Go versions.

The Go extension relies on [tools](https://github.com/golang/vscode-go/wiki/tools)
like `gopls` and `dlv` for its core functionalities and they have their own release
policy and schedule. We test only against the latest versions of these tools.

In case you need to work with an older version of Go, please check
the [Compatibility] page and manually install the compatible version of
the extension and tools.

## Contributing

We welcome your contributions and thank you for working to improve the Go
development experience in VS Code. If you would like to help work on the VS Code
Go extension, see our
[contribution guide](https://github.com/golang/vscode-go/wiki/contributing) to
learn how to build and run the VS Code Go extension locally and contribute to
the project.

## Code of Conduct

This project follows the
[Go Community Code of Conduct](https://golang.org/conduct). If you encounter a
conduct-related issue, please mail conduct@golang.org.

## License

[MIT](LICENSE)

[Stack Overflow]: https://stackoverflow.com/questions/tagged/go+visual-studio-code
[`gopls`]: https://golang.org/s/gopls
[`go`]: https://golang.org/cmd/go
[Managing extensions in VS Code]: https://code.visualstudio.com/docs/editor/extension-gallery
[VS Code Go extension]: https://marketplace.visualstudio.com/items?itemName=golang.go
[Go installation guide]: https://golang.org/doc/install
["Getting started with VS Code Go"]: https://youtu.be/1MXIGYrMk80
[IntelliSense]: https://github.com/golang/vscode-go/wiki/features#intellisense
[Code navigation]: https://github.com/golang/vscode-go/wiki/features#code-navigation
[Code editing]: https://github.com/golang/vscode-go/wiki/features#code-editing
[Compatibility]: https://github.com/golang/vscode-go/wiki/compatibility
[diagnostics]: https://github.com/golang/vscode-go/wiki/features#diagnostics
[testing]: https://github.com/golang/vscode-go/wiki/features#run-and-test-in-the-editor
[debugging]: https://github.com/golang/vscode-go/wiki/debugging#features
[full feature breakdown]: https://github.com/golang/vscode-go/wiki/features
[workspace documentation]: https://github.com/golang/tools/blob/master/gopls/doc/workspace.md
[`Go: Install/Update Tools` command]: https://github.com/golang/vscode-go/wiki/commands#go-installupdate-tools
[Supported workspace layouts documentation]: https://github.com/golang/tools/blob/master/gopls/doc/workspace.md
[Workspace Folders]: https://code.visualstudio.com/docs/editor/multi-root-workspaces

---

## File: docs/advanced.md

# Advanced topics

This document describes more advanced ways of working with the VS Code Go
extension.

## Formatting Code and Organizing Imports

When you have multiple formatter extensions, be sure to set this
extension as the default formatter for go language.
```json5
"[go]": {
  "editor.defaultFormatter": "golang.go"
}
```

Formatting and organizing imports are enabled by default. You
can choose to disable them by configuring the following settings.

```json5
"[go]": {
        "editor.formatOnSave": false,
        "editor.codeActionsOnSave": {
            "source.organizeImports": false
        }
}
```

## Choosing a different version of Go

The extension chooses the `go` command using the `PATH` (or `Path`) environment
variable by default. You can configure the extension to choose a different
version of `go` with one of the following options.

* (Preferred) Adjust your `PATH` or `Path` environment variable, and *open VS
  Code with the adjusted environment* variable, or
* Use the Go extension's `"Go: Choose Go Environment"` command that opens a
  [menu](ui.md) to change the `go` version, or
* Use the `"go.alternateTools"` settings and specify the absolute path to the
  `go` command. `"go.alternateTools": { "go": "/path/to/go/command" }`

**note**: For historical reasons, some users configure the `"go.goroot"`

settings or the `GOROOT` environment variable to select the Go SDK location.
With recent versions of Go, that's unnecessary in most cases.

## Configuring the installation of command-line tools

The `Go: Install/Update Tools` command uses the `go get` command to download and
install requested tools. By default, `go get` will install the compiled tools in
one of the following directories.

* the directory the `GOBIN` environment variable specifies, or
* the `bin` directory under the first `GOPATH` (or `"go.gopath"`) directory, or
* the `$HOME/go/bin` (or `$USERPROFILE/go/bin`) directory.

Some users prefer to choose a different installation location. In that case, use
the `"go.toolsGopath"` setting.

The extension finds the required tools by their names (`go`, `gopls`, `dlv`,
etc.). The `"go.alternateTools"` setting provides a way to configure the
extension to use different tool location, for example a wrapper with a different
name.

The extension uses pinned versions of command-line tools. See the pinned versions
in tools information
[here](https://github.com/golang/vscode-go/blob/master/extension/src/goToolsInformation.ts).
To use an alternate version of a tool install it manually with with go install.

## Using a custom linter

A commonly customized feature is the linter, which is the tool used to provide
coding style feedback and suggestions. This extension supports linters such as
`staticcheck`, `golangci-lint`, and `revive`. You can choose one of them using
the `"go.lintTool"` setting. For customization of the linter, please consult the
linter's documentation.

Note that if you are using `staticcheck`, you can enable it to run within
`gopls` by setting `"gopls": { "ui.diagnostic.staticcheck": true }`.

## Working on the Go standard library and the Go tools

This extension can be used for developing the standard library with additional
configuration.

First, you **must open the `src/` folder in VS Code**, not the Go tree root.

Then, you need to configure the workspace, by placing the following in
`src/.vscode/settings.json`. [Command Palette] ->
`Preferences: Open Workspace Settings (JSON)` will open the settings file.

```json5
{
  // Use the local go tool. This needs to be built with make.bash.
  "go.alternateTools": {
    "go": "~/godev/bin/go"
  },

  //
  // Below is optional.
  //
  // Build a separate set of tools. For golang/vscode-go#294.
  "go.toolsGopath": "~/.vscode/godev",
  // Don't reformat HTML files since we have a custom style.
  "html.format.enable": false
}
```

The above assumes the Go tree is checked out at `~/godev`. If your Go tree is
somewhere else, modify `go.alternateTools.go` to point to the go *binary*
accordingly. Many underlying tools including `gopls` invoke the go command
(`go list`, etc), so we assume the binary isn't completely broken.

You can add `.vscode` to `.git/info/exclude` to avoid risking checking
`settings.json` into git.

If you see an "inconsistent vendoring" error, please report it at
[golang/go#40250](https://github.com/golang/go/issues/40250).



[Command Palette]: https://code.visualstudio.com/docs/getstarted/userinterface#_command-palette

---

## File: docs/commands.md

# Commands

In addition to integrated editing features, this extension offers a number of commands, which can be executed manually through the [Command Palette](https://code.visualstudio.com/docs/getstarted/userinterface#_command-palette) (Ctrl+Shift+P on Linux/Windows or Cmd+Shift+P on Mac OS).

Some of these commands are also available in the VS Code context menu (right-click). To control which of these commands show up in the editor context menu, update the [`"go.editorContextMenuCommands"`](settings.md#go.editorContextMenuCommands) setting.

All commands provided by this extension have the prefix `Go:`.

## Latest changes

The commands described below are up-to-date as of June 2020. We do our best to keep documentation current, but if a command is missing, you can always consult the full list in the Extensions view.

To view this list:

1. Navigate to the Extensions view (Ctrl+Shift+X).
2. Find the Go extension and click on it to open the Extension Editor.
3. Click on the `Feature Contributions` tab.
4. Scroll through the list under `Commands`.

Finally, you can also see a full list by using a meta command: `Go: Show All Commands...`.

## Detailed list



### `Go: Open in new Document`

Open selected variable in a new document.

### `Go: Current GOPATH`

See the currently set GOPATH.

### `Go: Current GOROOT`

See the currently set GOROOT.

### `Go: Locate Configured Go Tools`

List all the Go tools being used by this extension along with their locations.

### `Package Outline: Sort By Name`

Sort Package Outline symbols alphabetically.

### `Package Outline: Sort By Position`

Sort Package Outline symbols by source position.

### `Go: Test Function At Cursor`

Runs a unit test at the cursor.

### `Go: Test Function At Cursor or Test Previous`

Runs a unit test at the cursor if one is found, otherwise re-runs the last executed test.

### `Go: Subtest At Cursor`

Runs a sub test at the cursor.

### `Go: Debug Subtest At Cursor`

Debug a sub test at the cursor.

### `Go: Benchmark Function At Cursor`

Runs a benchmark at the cursor.

### `Go: Debug Test At Cursor`

Debug test at the cursor.

### `Go: Test File`

Runs all unit tests in the current file.

### `Go: Test Package`

Runs all unit tests in the package of the current file.

### `Go: Toggle Hide System Goroutines`

Toggles hiding the system goroutines from the active debug session call stack view.

### `Go Test: Refresh`

Refresh a test in the test explorer. Only available as a context menu option in the test explorer.

### `Go Test: Show Last Profile`

Show last captured profile

### `Go Test: Profile`

Run a test and capture a profile

### `Go Test: Delete Profile`

Delete selected profile

### `Go: Show pprof file`

Internal use. Open a pprof profile file.

### `Go: Benchmark Package`

Runs all benchmarks in the package of the current file.

### `Go: Benchmark File`

Runs all benchmarks in the current file.

### `Go: Test All Packages In Workspace`

Runs all unit tests from all packages in the current workspace.

### `Go: Test Previous`

Re-runs the last executed test.

### `Go: Debug Previous`

Re-runs the last debugged test run through a codelens or "Go: Debug Test at Cursor" command.

### `Go: Toggle Test Coverage In Current Package`

Displays test coverage in the current package.

### `Go: Generate Unit Tests For Package`

Generates unit tests for the current package using gotests

### `Go: Generate Unit Tests For File`

Generates unit tests for the current file using gotests

### `Go: Generate Unit Tests For Function`

Generates unit tests for the selected function in the current file using gopls

### `Go: Generate Unit Tests For Function (legacy)`

Generates unit tests for the selected function in the current file using gotests

### `Go: Generate Interface Stubs`

Generates method stub for implementing the provided interface for the type at the cursor using gopls.

### `Go: Generate Interface Stubs (legacy)`

Generates method stub for implementing the provided interface and inserts at the cursor using impl.

### `Go: Extract Language Server Logs To Editor`

Extract logs in the `gopls (server)` output channel to the editor.

### `Go: Welcome`

Open the welcome page for the Go extension.

### `Go: Toggle compiler optimization details`

Toggle the per-package flag that causes compiler optimization details to be reported as diagnostics

### `Go: Add Import`

Add an import declaration

### `Go: Add Package to Workspace`

Add a package from the imports list to the workspace.

### `Go: Install/Update Tools`

install/update the required go packages

### `Go: Toggle Test File`

Toggles between file in current active editor and the corresponding test file.

### `Go: Toggle Vulncheck`

Toggle the display of vulnerability analysis in dependencies.

### `Go: Start language server's maintainer interface`

Start the Go language server's maintainer interface (a web server).

### `Go: Add Tags To Struct Fields`

Add tags configured in go.addTags setting to selected struct using gomodifytags (via gopls)

### `Go: Remove Tags From Struct Fields`

Remove tags configured in go.removeTags setting from selected struct using gomodifytags (via gopls)

### `Go: Show All Commands...`

Shows all commands from the Go extension in the quick pick

### `Go: Browse Packages`

Browse packages and Go files inside the packages.

### `Go: Get Package`

Run `go get -v` on the package on the current line.

### `Go: Run on Go Playground`

Upload the current selection or file to the Go Playground

### `Go: Lint Current Package`

Run linter in the package of the current file.

### `Go: Lint Workspace`

Run linter in the current workspace.

### `Go: Vet Current Package`

Run go vet in the package of the current file.

### `Go: Vet Workspace`

Run go vet in the current workspace.

### `Go: Build Current Package`

Build the package of the current file.

### `Go: Build Workspace`

Build the current workspace.

### `Go: Install Current Package`

Install the current package.

### `Go: Initialize go.mod`

Run `go mod init` in the workspace folder.

### `Go: Cancel Running Tests`

Cancels running tests.

### `Go: Apply Cover Profile`

Applies existing cover profile.

### `Go: Restart Language Server`

Restart the running instance of the language server

### `Go: Choose Go Environment`

Choose a different Go version or binary for this project. (WIP)

### `Go: Show Survey Configuration`

Show the current Go survey configuration

### `Go: Reset Survey Configuration`

Reset the current Go survey configuration history

### `Go: Reset Workspace State`

Reset keys in workspace state to undefined.

### `Go: Reset Global State`

Reset keys in global state to undefined.

### `Go Explorer: Refresh`

Refresh the Go explorer. Only available as a menu item in the explorer.

### `Go Explorer: Open File`

Open a file from the Go explorer. Only available as a menu item in the explorer.

### `Go: Edit Workspace Env`

Edit the Go Env for the active workspace.

### `Go: Reset Workspace Env`

Reset the Go Env for the active workspace.

---

## File: docs/compatibility.md

## Version Compatibility

The table below lists the *last* version of the extension
known to be compatible with old versions of Go, and the last versionof tools
compatible with it.

| Go version | Extension version | VS Code | Gopls     | Delve        |
| ---------- | ----------------- | ------- | --------- | ------------ |
| go1.20     | v0.42.1           | 1.75+   | v0.15.3   | v1.22.1      |
| go1.19     | v0.42.1           | 1.75+   | v0.15.3   | v1.21.2      |
| go1.18     | v0.41.3           | 1.75+   | v0.14.2   | v1.20.0      |
| go1.17     | v0.39.1           | 1.67+   | v0.11.0   | v1.9.1       |
| go1.16     | v0.39.1           | 1.67+   | v0.11.0   | v1.8.3       |

### References
  * Gopls's [supported go versions](https://github.com/golang/tools/tree/master/gopls#supported-go-versions).
  * Delve's [supported go versions](https://github.com/go-delve/delve/blob/master/pkg/goversion/compat.go).

---

## File: docs/contributing.md

# Contributing

We welcome your contributions and thank you for working to improve the Go development experience in VS Code.

This guide will explain the process of setting up your development environment to work on the VS Code Go extension, as well as the process of sending out your change for review.

Our canonical Git repository is located at https://go.googlesource.com/vscode-go and https://github.com/golang/vscode-go is a mirror.

* [Before you start coding](#before-you-start-coding)
  * [Ask for help](#ask-for-help)
  * [Debug Adapter](#debug-adapter)
* [Developing](#developing)
  * [Setup](#setup)
  * [Run](#run)
  * [Test](#test)
  * [Sideload](#sideload)
* [Mail your change for review](#mail-your-change-for-review)
  * [Presubmit test in CI](#presubmit-test-in-ci)

## Before you start coding

If you are interested in fixing a bug or contributing a feature, please [file an issue](https://github.com/golang/vscode-go/issues/new/choose) first. Wait for a project maintainer to respond before you spend time coding.

If you wish to work on an existing issue, please add a comment saying so, as someone may already be working on it. A project maintainer may respond with advice on how to get started. If you're not sure which issues are available, search for issues with the [help wanted label](https://github.com/golang/vscode-go/labels/HelpWanted).

### Ask for help

The VS Code Go maintainers are reachable via the issue tracker and the [#vscode-dev] channel in the [Gophers Slack]. Please reach out on Slack with questions, suggestions, or ideas. If you have trouble getting started on an issue, we'd be happy to give pointers and advice.

### Language Server (`gopls`)

Many of the language features like auto-completion, documentation, diagnostics are implemented
by the Go language server ([`gopls`](https://pkg.go.dev/golang.org/x/tools/gopls)).
This extension communicates with `gopls` using [vscode LSP client library](https://github.com/microsoft/vscode-languageserver-node) from [`language/goLanguageServer.ts`](https://github.com/golang/vscode-go/tree/master/src/language).

For extending the language features or fixing bugs, please follow `gopls`'s
[contribution guide](https://github.com/golang/tools/blob/master/gopls/doc/contributing.md).

### Debug Adapter (`dlv dap`)

Debugging features are implemented by Delve (`dlv`) and its native DAP implementation
([`dlv dap`](https://github.com/go-delve/delve/blob/master/Documentation/api/dap/README.md)).

* goDebugConfiguration.ts: where launch configuration massaging occurs.
* goDebugFactory.ts: where a thin adapter that communicates with the `dlv dap` process is defined.
* [github.com/go-delve/delve](https://github.com/go-delve/delve/tree/master/service/dap): where native DAP implementation in Delve exists.

For extending the features of Delve, please follow `Delve` project's [contribution guide](https://github.com/go-delve/delve/blob/master/CONTRIBUTING.md).

The debugging feature documentation has a dedicated section for tips for development (See ["Developing"](https://github.com/golang/vscode-go/blob/master/docs/debugging.md#developing) section).

## Developing

### Setup

1) Install [node](https://nodejs.org/en/). Note: make sure that you are using `npm v7` or higher. The file format for `package-lock.json` (changed significantly)[https://docs.npmjs.com/cli/v7/configuring-npm/package-lock-json#file-format] in `npm v7`.
2) Clone the repository, run `npm ci`, and open VS Code:

    ```bash
    git clone https://go.googlesource.com/vscode-go
    cd vscode-go/extension
    npm ci
    code .
    ```

#### Lint

You can run `npm run lint` on the command-line to check for lint errors in your program. You can also use the [ESLint](https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint) plugin to see errors as you code.

### Run

To run the extension with your patch, open the Run view (`Ctrl+Shift+D` or `⌘+⇧+D`), select `Launch Extension`, and click the Play button (`F5`).

This will open a new VS Code window with the title `[Extension Development Host]`. You can then open a folder that contains Go code and try out your changes.

You can also set breakpoints to debug your change.

If you make subsequent edits in the codebase, you can reload (`Ctrl+R` or `⌘+R`) the `[Extension Development Host]` instance of VS Code, which will load the new code. The debugger will automatically reattach.

## Test

1. `export GOPATH=/path/to/gopath/for/test`
2. `cd extension` -- most extension development work is done in the `extension` directory.
2. `go run tools/installtools/main.go` -- this will install all tools in the `GOPATH/bin` built from master/main.
3. There are currently two different types of tests in this repo:
  - `npm run unit-test`: this runs unit tests defined in `test/unit`. They are light-weight tests that don't require `vscode` APIs.
  - `npm run test`: this runs the integration tests defined in `test/integration` and `test/gopls`. They test logic that involve `vscode` APIs - which requires actually downloading & running Visual Studio Code (`code`) and loading the compiled extension/test code in it.
4. Before sending a CL, make sure to run
  - `npm run lint`: this runs linter.
  - `go run tools/generate.go -w=false -gopls=true`: this checks generated documentations are up-to-date.

### Testing Tips

#### (1) Running only a subset of integration or unit tests:
When running them from terminal:
  - Option 1: Utilize `MOCHA_GREP` environment variable. That is equivalent with [`mocha --grep` flag](https://mochajs.org/#command-line-usage) that runs tests matching the given string or regexp. E.g. `MOCHA_GREP=gopls npm run test` which runs all integration tests whose suite/test names contain `"gopls"`.
  - Option 2: modify the test source code and set the [`only`](https://mochajs.org/#exclusive-tests) or [`skip`](https://mochajs.org/#inclusive-tests) depending on your need. If necessary, you can also modify `test/integration/index.ts` or `test/gopls/index.ts` to include only the test files you want to focus on. Make sure to revert them before sending the changes for review.

#### (2) Debugging tests from VS Code:
`.vscode/launch.json` defines test launch configurations. To run the tests locally, open the Run view (`Ctrl+Shift+D`), select the relevant launch configuration, and hit the Play button (`F5`). Output and results of the tests, including any logging written with `console.log` will appear in the `DEBUG CONSOLE` tab.
You can supply environment variables (e.g. `MOCHA_GREP`) by modifying the launch configuration entry's `env` property.
  - `Launch Unit Tests`: runs unit tests in `test/unit` (same as `npm run unit-test`)
  - `Launch Extension Tests`: runs tests in `test/integration` directory (similar to `npm run test` but runs only tests under `test/integration` directory)
  - `Launch Extension Tests with Gopls`: runs tests in `test/gopls` directory (similar to `npm run test` but runs only tests under `test/gopls` directory)

When you want to filter tests while debugging, utilize the `MOCAH_GREP` environment variable discussed previously - i.e., set the environment variable in the `env` property of the launch configuration.

#### (3) Using different versions of tools.
The tests will pick tools found from `GOPATH/bin` first. So, install the versions you want there.

## Running/Debugging the Extension

Select the [`Launch Extension`](https://github.com/golang/vscode-go/blob/e2a7fb523acffea3427ad7e369c3b2abc30b775b/.vscode/launch.json#L13) configuration, and hit the Play button (`F5`). This will build the extension and start a new VS Code window with the title `"[Extension Development Host]"` that uses the newly built extension. This instance has the node.js debugger attached automatically. You can debug using the VS Code Debug UI of the main window (e.g. set breakpoints, inspect variables, step, etc)

The VS Code window may have the folder or file used during your previous testing. If you want to change the folder during testing, close the folder by using "File > Close Folder", and open a new folder from the VS Code window under test.

### Debugging interaction with `gopls`

When developing features in `gopls`, you may need to attach a debugger to `gopls` and configure the extension to connect to the `gopls` instance using [the gopls deamon mode](https://github.com/golang/tools/blob/master/gopls/doc/daemon.md).

1. Start a gopls in deamon mode:
```
gopls -listen=:37374 -logfile=auto -debug=:0 serve
```

Or, if you use vscode for gopls development, you can configure `launch.json` of the `x/tools/gopls` project:

```
...
  {
    "name": "Launch Gopls",
    "type": "go",
    "request": "launch",
    "mode": "auto",
    "program": "${workspaceFolder}/gopls",
    "args": ["-listen=:37374", "-logfile=auto", "-debug=:0"],
    "cwd": "<... directory where you want to run your gopls from ...",
  }
...
```

2. Start the extension debug session using the `Launch Extension` configuration.

3. Configure the settings.json of the project open in the `"[Extension Development Host]"` window to start `gopls` that connects to the gopls we started in the step 1.

```
  "go.languageServerFlags": ["-remote=:37374", "-rpc.trace"]
```

## Sideload

After making changes to the extension, you may want to test it end-to-end instead of running it in debug mode. To do this, you can sideload the extension.

1. `cd` into the `extension` directory.
3. Install all dependencies by running `npm ci`.
4. Run `npx vsce package`. This will generate a file with a `.vsix` extension in your current directory.

    ```bash
    npm install vsce
    cd vscode-go
    npm ci
    vsce package
    ```

5. Open a VS Code window, navigate to the Extensions view, and disable or uninstall the default Go extension.
6. Click on the "..." in the top-right corner, select "Install
from VSIX...", and choose the generated VSIX file. Alternatively, you can run `code --install-extension path/to/go.vsix` or open the Command Palette and run the `Extensions: Install from VSIX...` command.

## Mail your change for review

Once you have coded, built, and tested your change, it's ready for review! There are two ways to mail your change: (1) through [a GitHub pull request (PR)](https://golang.org/doc/contribute.html#sending_a_change_github), or (2) through a [Gerrit code review](https://golang.org/doc/contribute.html#sending_a_change_gerrit).

In either case, code review will happen in [Gerrit](https://www.gerritcodereview.com/), which is used for all repositories in the Go project. We strongly recommend the Gerrit code review if you plan to send many changes. GitHub pull requests will be mirrored into Gerrit, so you can follow a more traditional GitHub workflow, but you will still have to look at Gerrit to read comments.

The easiest way to start is by reading this [detailed guide for contributing to the Go project](https://golang.org/doc/contribute.html). Important things to note are:

* You will need to sign the [Google CLA](https://golang.org/doc/contribute.html#cla).
* Your commit message should follow the standards described on the [Commit Message Wiki](https://github.com/golang/go/wiki/CommitMessage).
* Your change should include tests (if possible).

Once you've sent out your change, a maintainer will take a look at your contribution within a few weeks. If you don't hear back, feel free to ping the issue or send a message to the [#vscode-dev] channel of the [Gophers Slack].

### Presubmit Test in CI

When you mail your CL or upload a new patch to an existing CL, *AND*
you or a fellow contributor assigns the `Commit-Queue=+1` label in Gerrit, all the
tests (including go test and typescript test) defined in vscode-go will be
triggered by `LUCI`.

`LUCI` will post the result as a comment, and add its `LUCI-TryBot-Result` vote
after all tests run completes.

To force a re-run of the LUCI CI, re-assigns the `Commit-Queue=+1` label in Gerrit.

[#vscode-dev]: https://gophers.slack.com/archives/CUWGEKH5Z
[Gophers Slack]: https://invite.slack.golangbridge.org/

---

## File: docs/debug-adapter.md

# Debug Adapter

The [Debug Adapter](../src/debugAdapter) runs in a separate Node.js process, which is spawned by VS Code when you debug Go code.

Please see the [Debug Adapter Protocol (DAP)](https://microsoft.github.io/debug-adapter-protocol/) to understand how the Debug Adapter acts as an intermediary between VS Code and the debugger ([Delve](https://github.com/go-delve/delve)).

This codebase is currently in flux: We are working on using [`Delve`'s native DAP implementation](https://github.com/go-delve/delve/tree/master/service/dap) instead of this one. Follow along with [golang/vscode-go#23](https://github.com/golang/vscode-go/issues/23) for updates on that work.

## Overview

* [Before you begin](#before-you-begin)
* [Debug only the Debug Adapter](#debug-only-the-debug-adapter)
* [Debug the VS Code extension and the Debug Adapter](#debug-the-entire-extension-including-the-debug-adapter)
* [Debug VS Code and the Debug Adapter](#debug-vs-code-and-the-debug-adapter)

## Before you begin

Before you start working on your change, please read the [contribution guidelines](contributing.md). This document assumes that you are already familiar with the process of [building](contributing.md#setup), [running](contributing.md#run), and [sideloading](contributing.md#sideload) the VS Code Go extension.

## Debug only the Debug Adapter

As a next step, you may want to debug the Debug Adapter, in order to understand how your change work with [Delve](tools.md#delve).

**NOTE: Since the Debug Adapter runs in a separate process from the rest of the extension, the steps below only enable you to debug the Debug Adapter code, not the entire extension. To debug the entire extension, as well as the debug adapter, see the instructions [below](#debug-the-entire-extension).**

1. Open the `vscode-go` folder in VS Code.
2. Go to the Run view and choose the `Launch as server` debug configuration.
3. Add breakpoints as needed to the [`vscode-go/src/debugAdapter/goDebug.ts`](../src/debugAdapter/goDebug.ts) file.
4. Open another instance of VS Code and open the Go project to debug.
5. Create a debug configuration for the Go project if it doesn't exist. Set `"debugServer": 4711` in the root of the configuration.
6. Start debugging your Go program using this configuration. This will trigger the breakpoints in [`goDebug.ts`](../src/debugAdapter/goDebug.ts) file.

## Debug the entire extension, including the Debug Adapter

You can take this step if your change modifies both the Debug Adapter and the main extension.

1. Open the `vscode-go` folder in VS Code.
2. Go to the Run view and choose the `Extension + Debug server` debug configuration. This combines `Launch Extension` and `Launch as server` debug configurations.
3. Add breakpoints as needed and start debugging (`F5`). It will start an Extension Development Host window and the Debug Adapter server process at port 4711. Debuggers are attached to both processes and the breakpoints will apply to both of them.
4. In the Extension Development Host window, open the Go application source code you'd like to debug. As above, create a debug configuration pointing to the program you want to debug. Add `"debugServer": 4711` to the root of the configuration. Then, run the debug configuration (`F5`), which will start debugging the Go application.
5. Combined debug information (call stacks, breakpoints, etc.) of the debugged Extension Development Host and the Debug Adapter will be displayed in the debug view of the original VS Code window. You can use the drop-down menu in the Debug toolbar to switch between the two instances (`Launch Extension` and `Launch as server`).

## Debug VS Code and the Debug Adapter

In some very rare cases, you may find it helpful to debug VS Code itself. An example of such a case might be verifying workbench behavior and state before executing debug adapter API calls.

First, ensure that you can [build and run VS Code](https://github.com/Microsoft/vscode/wiki/How-to-Contribute#build-and-run) from source successfully.

Next, follow these steps:

1. Open an instance of VS Code that you have built from source.
2. [Sideload](contributing.md#sideload) your local `vscode-go` extension to the local instance of VS Code. This can be done by copying the contents of the `vscode-go` directory into `$HOME/.vscode-oss-dev/extensions/ms-vscode.go` (the exact location may vary by OS).
3. Open the `vscode` folder in Visual Studio Code.
4. Launch the VS Code debug instance (OSS - Code) by choosing the `Launch VS Code` debug configuration from the drop-down in the Run view. Add breakpoints as needed.
5. In another instance of VS Code, open the `vscode-go` folder. Choose the `Launch as server` debug configuration in the Run view. Add breakpoints as desired in the [`vscode-go/src/debugAdapter/goDebug.ts`](../src/debugAdapter/goDebug.ts) file.
6. Open the Go application you want to debug in the OSS Code instance initiated in step 4.
7. Create a debug configuration with the setting `"debugServer": 4711`.
8. Start debugging your Go application. Observe that any breakpoints you set in the VS Code and debug adapter codebases will be triggered.

---

## File: docs/debugging.md

# Debugging

The Go extension allows you to launch or attach to Go programs for debugging.
You can inspect variables and stacks, set breakpoints, and do other debugging
activities using
[VS Code’s Debugging UI](https://code.visualstudio.com/docs/editor/debugging).

These debugging features are possible by using
[Delve](https://github.com/go-delve/delve), the Go debugger.

Previously, the Go extension communicated with Delve through a custom debug
adaptor program (`legacy` mode). Since
[`Delve`'s native debug adapter implementation](https://github.com/go-delve/delve/tree/master/service/dap)
is available, the Go extension is transitioning to deprecate the legacy debug
adapter in favor of direct communication with Delve via
[DAP](https://microsoft.github.io/debug-adapter-protocol/overview).


 📣 **We are happy to announce that the new _`dlv-dap`_ mode of Delve
 integration is enabled for _local_ _debugging_ by default. For
 [_remote_ _debugging_](#remote-debugging) it is the default in
 [pre-release versions](https://github.com/golang/vscode-go/blob/master/README.md#pre-release-version) and is available with stable builds on demand with
 `"debugAdapter": "dlv-dap"` attribute in `launch.json` or `settings.json`!**

Many features and settings described in this document may be available only with
the new `dlv-dap` mode. For troubleshooting and configuring the legacy debug
adapter, see
[the legacy debug adapter documentation](https://github.com/golang/vscode-go/tree/master/docs/debugging-legacy.md).

## Get started

Open a file to debug (either `package main` source file or the test file) in the
editor, and select the `Run and Debug` button from
[the Run view](https://code.visualstudio.com/docs/editor/debugging#_run-view).
Alternatively, you can start debugging using `Start Debugging (F5)` command from
[the Run menu](https://code.visualstudio.com/docs/editor/debugging#_run-menu) or
from
[the Command Palette](https://code.visualstudio.com/docs/getstarted/userinterface#_command-palette)
(Linux/Windows: Ctrl+Shift+P, Mac: ⇧+⌘+P).

If you already have launch configurations for the project
(`.vscode/launch.json`), the Run view will display the configuration list to
choose from.

When no configuration is configured yet (no `.vscode/launch.json` file), the
extension will choose a default configuration based on the file open in the
editor.

❗ When you start debugging for
the first time or if the `dlv` executable on your system is too old to support
DAP, the Go extension may ask to install or update Delve. Follow the
instructions to install it, and then start the debugging session again.



To learn more about debugging in Go, watch
[Go: Writing and debugging fast, reliable, and efficient software](https://www.youtube.com/watch?v=6r08zGi38Tk&list=PLj6YeMhvp2S40Q-TEPEKOeypLvTVd5uME&index=1).

Review the [Features](#features) section for an overview of
the Go Extension's debug UI and available features.

### Stay up to date

[Delve’s native DAP implementation](https://github.com/go-delve/delve/tree/master/service/dap)
is under active development. Take advantage of the most recent features and bug
fixes by installing the latest version of `dlv` using the
**`Go:Install/Update`** Tools command from the Command Palette (Linux/Windows:
`Ctrl`+`Shift`+`P`, Mac: `Command`+`Shift`+`P`). The command will show `dlv` in
the tool list.

Once `dlv` is installed on your system, the extension will prompt you for update
whenever installing a newer version is necessary. You can set the
`go.toolsManagement.autoUpdate` setting so the extension can update `dlv`
automatically for you.

If you need to install `dlv` manually outside of VS Code, follow the instruction
in [Manually installing `dlv`](debugging.md#manually-installing-dlv). An example
of a situation where manual installation might be needed is if you are building
a dev container with the necessary tools preinstalled, or installing `dlv` built
from the tree head.

### Switch to legacy debug adapter

Note: The extension still uses the legacy debug adapter for remote debugging.

If you need to use the legacy debug adapter for local debugging (`legacy` mode)
by default, add the following in your VSCode settings.

```json
    "go.delveConfig": {
        "debugAdapter": "legacy",
    }
```

When `mode` is set to `remote` you must explicitly set `debugAdapter` to
`dlv-dap` to override the legacy adapter default.

If you want to switch to `legacy` for only a subset of your launch
configurations, you can use
[the `debugAdapter` attribute](#launchjson-attributes) to switch between
`"dlv-dap"` and `"legacy"` mode.

If you chose to switch to legacy because of bugs or limitations in the new debug
adapter, [open an issue](https://github.com/golang/vscode-go/issues/new)
to help us improve.

## Features

For general debugging features such as inspecting variables, setting
breakpoints, and other activities that aren't language-dependent, review
[VS Code debugging](https://code.visualstudio.com/docs/editor/debugging).

### Configure

When you need more than the default debugging setup, you can create a launch
configuration file for the project.

To create a configuration file:

1. In the
   [the Run view](https://code.visualstudio.com/docs/editor/debugging#_run-view),
   click "create a launch.json file"
1. Choose **Go: Launch Package** from the debug configuration drop-down menu. VS
   Code will create a `launch.json` file in a .vscode folder in your workspace
   (project root folder) or in your
   [user settings](https://code.visualstudio.com/docs/editor/debugging#_global-launch-configuration)
   or
   [workspace settings](https://code.visualstudio.com/docs/editor/multi-root-workspaces#_workspace-launch-configurations).



If you already have a `launch.json` for your project, you can open it using the
Command Palette **Open launch.json** command.

To add a new configuration to an existing `launch.json` file:

1. Open your `launch.json` file using the Command Palette **Open launch.json**
   command.
1. Click the **Add Configuration** button to invoke the snippet IntelliSense.

There are many configuration attributes (see
[the Launch.json attributes](#launchjson-attributes) section). IntelliSense in
VS Code’s `launch.json` editor will help you navigate available options and
documentation.

### Launch

To launch and debug your project, select **Run** > **Start Debugging (F5)**.

The launch feature uses a `launch` request type configuration in your
`launch.json` file. Its `program` attribute needs to be the absolute path to
either the Go file, or folder containing the main package or test file. In this
mode, the Go extension will start the debug session by building and launching
the program. The launched program will be terminated when the debug session
ends.

* Supported modes
  * `debug`: build and debug a main package
  * `test`: build and debug a test
  * `exec`: debug a precompiled binary
    * The binary must be built with `go build -gcflags=all="-N -l"` to disable
      inlining and optimizations that can interfere with debugging.
  * `auto`: automatically choose between `debug` and `test` depending on the
    open file

⚠️ For ["Remote Debugging"](#remote-debugging), add the `port` attribute to the
launch configuration. VS Code will connect to the external user-specified
`dlv dap` server at `host:port` and launch the target there.

For remote debugging, the `program` attribute must point to the absolute path to
the package or binary to debug in the remote host’s file system even when
`substitutePath` is specified.

### Attach

You can use this configuration to attach to a running process or a running debug
session.

* Supported modes
  * `local`: attaches to a local process.
    * The binary must be built with `go build -gcflags=all="-N -l"` to disable
      inlining and optimizations that can interfere with debugging.
  * `remote`: attaches to an in-progress debug session run by an external
    server.

You can debug an already running program using the `local` mode type
configuration. The Go extension will start `dlv dap` and configure it to attach
to the specified process. Users can select the process to debug with one of the
following options:

* Specifying the numeric process id (PID) with the `processId` attribute.
* Specifying the target program name in the `processId` attribute. If there are
  multiple processes matching the specified program name, the extension will
  show the list of matching processes at the start of the debug session.
* Specifying `0` in the `processId` attribute and selecting the process from the
  drop-down menu at the start of the debug session.



NOTE: For remote debugging, add the `port` attribute to
the launch configuration. VS Code will connect to the external user-specified
`dlv dap` server at `host:port` and attach to the target there.See
["remote debugging"](#remote-debugging) for more details).

You can connect to an already running remote debug session using the `remote`
mode. Specify optional `host` and required `port` for the external
`dlv --headless` server that already took program or process id details as
command-line arguments. See ["Remote Debugging"](#remote-debugging) for more
details).

When you end an attach debug session, the debug UI allows you to choose to:

* [DEFAULT] Disconnect: disconnect the client and:
  * `local`: leave the target process running (dlv terminates).
  * `remote`: let dlv decide if it can continue running (`--accept-multiclient`
    mode only); if so, the target will stay in halted or running state it was in
    at disconnect.
    * `dlv debug/test/exec`: terminate the target process if dlv terminates.
    * `dlv attach`: leave the target process running even if dlv terminates.
* Stop: stop the attached server and the target process.





### Debug actions

Once a debug session starts, the Debug toolbar will appear on the top of the
editor.



The available commands are:

* Continue / Pause F5
* Step Over (aka `next` in Delve) F10
* Step Into (aka `step` in Delve) F11
* Step Out (aka `stepout` in Delve) Shift+F11 or ⇧F11
* Restart (currently this is "Stop + Start") Ctrl+Shift+F5 or ⇧⌘F5
* Stop (terminate the debugee. Available in Launch request) Shift+F5 or ⇧F5
* Disconnect (detach from the debugee. Available only in Attach request)
  Shift+F5 or ⇧F5
* Terminate (terminate the debugee. Available only in Attach request)
  Alt+Shift+F5 or ⌥⇧F5

### Breakpoints

See
[VS Code’s Debug Documentation on Breakpoints](https://code.visualstudio.com/docs/editor/debugging#_breakpoints)
to get familiar with VS Code’s UI. The Go debugger supports multiple ways to
configure breakpoints.

* **Breakpoints**: you can set breakpoints by clicking on the editor margin or
  using F9 on the current line. If the breakpoints can’t be set by Delve, VS
  Code will show the failure reason and grey out the dot.



* **Conditional breakpoints**: you can specify breakpoint conditions (similar to
  Delve’s
  [`condition` command](https://github.com/go-delve/delve/tree/master/Documentation/cli#condition)).
  * Expression condition: takes a boolean expression.
  * Hit count: supports comparison operators (`>`, `>=`, `<`, `<=`, `==`, `!=`)
    with an integer value. `% n` form means we should stop at the breakpoint
    when the hitcount is a multiple of `n`.



* **Function Breakpoints**: breakpoints can be set based on function names.
  Press the + button in the BREAKPOINTS section header and enter the location in
  the form of `<function>[:<line>]`. This sets the breakpoint in the `line`
  inside the `function`. The full syntax for `function` is
  `.(*<receiver type>).<function_name>` as specified in
  [Delve’s location spec](https://github.com/go-delve/delve/blob/master/Documentation/cli/locspec.md#location-specifiers).
  Function breakpoints are shown with a red triangle in the BREAKPOINTS section.



* **Logpoints**: a
  [logpoint](https://code.visualstudio.com/docs/editor/debugging#_logpoints) is
  a variant of breakpoint that does not 'break', but instead logs a message to
  DEBUG CONSOLE and continues execution. Expressions within `{}` are
  interpolated. For the list of acceptable expressions and syntax, see
  [Delve's documentation](https://github.com/go-delve/delve/blob/master/Documentation/cli/expr.md#expressions).

### Data inspection

You can inspect variables in the VARIABLES section of the Run view or by
hovering over their source in the editor. Variable values and expression
evaluation are relative to the selected stack frame in the CALL section.

By default, the VARIABLES section hides global variables, and shows only local
variables and function arguments. However, you can still inspect global
variables from the DEBUG CONSOLE panel. If you prefer to have the VARIABLES
section show global variables, set the `showGlobalVariables` attribute in the
`launch.json` configuration, or set it in the `go.delveConfig` setting.

When you select a variable and right click from the VARIABLES section, the
context menu will present shortcuts to features such as:

* `Set Value`: you can set/modify simple string, numeric, pointer values. Using
  composite literals, or memory allocation is not supported.
* `Copy Value`: this copies the value in clipboard.
* `Copy as Expression`: this is useful when you need to query from the REPL in
  the DEBUG CONSOLE panel.
* `Add to Watch`: this will automatically add the expression to the WATCH
  section.

Shadowed variables will be marked with `()`.



⚠️ Delve debugger imposes variable loading limits to prevent loading too many
variables at once and negatively impacting debugging latency. The `dlv-dap` mode
uses a different approach. It takes advantage of the interactive UI features to
provide on-demand loading of individual variables, paging of arrays, slices and
maps and increased string limits depending on the context. We continue to
explore additional interactive features to balance performance and usability of
variable loading and look forward to your feedback.

You can inspect variables and evaluate expressions from the DEBUG CONSOLE panel
too. Acceptable expressions are either

* A valid
  [Delve expression](https://github.com/go-delve/delve/blob/master/Documentation/cli/expr.md),
  or
* `call <function_call_expression>` to call functions.



Variables and expressions accepted in DEBUG CONSOLE can be also registered in
the Run view’s WATCH section, so they can be evaluated automatically as you
debug. The "Add to Watch" feature from the VARIABLES section is convenient when
you want to register interesting variables.

⚠️ Function call feature is highly EXPERIMENTAL due to the limitation in Go
runtime. Registering function calls in the WATCH section can often be
problematic. Pause, stop, and disconnect will not work while a function call is
running.

Hover over variables in editors during debugging shows the value of the
variable. For this feature, VS Code extracts the variable expression and makes a
request to the debugger to evaluate the expression. Delve evaluates the
expression relative to the highlighted stack frame chosen in the CALL STACK. By
default, that is the current top-most frame.



⚠️ Limitation

* VS Code heuristically determines the variable expression without full
  understanding of the scope & the currently selected frame. Delve tries to
  evaluate the provided expression in the selected frame. As a result, hover
  over variables outside the selected frame’s function may present incorrect
  information.

### Call stack

You can inspect all goroutines and their stacks in the CALL STACK section. The
CALL STACK section UI allows switching between goroutines or selecting a
different stack frame. As a different stack frame or different goroutine is
selected, the scope shown in the VARIABLE section will be updated for the newly
selected stack frame, and the expressions in the WATCH section will be
automatically reevaluated relative to the newly selected stack frame.



1. Goroutine stacks are annotated with their internal goroutine IDs.
2. The current goroutine is marked with `*`. If multiple goroutines stop (e.g.
   hit breakpoints) concurrently, Delve will pick one randomly. There also might
   not be a current goroutine (e.g. deadlock, pause or internal breakpoint hit
   by a system thread not running a goroutine).
3. If you click a goroutine call stack from the CALL STACK section, the
   goroutine is _selected_.
4. You can select a frame of the selected goroutine. The VARIABLE and WATCH
   sections will be updated accordingly and the cursor in the editor will be
   moved to the corresponding location in the source code.
5. Runtime stack frames are deemphasized (greyed out or collapsed).
6. Thread IDs are shown for scheduled goroutines.
7. Stop reason. It’s possible that there are multiple reasons goroutines were
   stopped, but currently only one reason is presented.
8. File name and line number of the frame.
9. You can trigger a debug action with the selected goroutine. Note: Resuming or
   stopping only a single goroutine (Go Issue
   [25578](https://github.com/golang/go/issues/25578),
   [31132](https://github.com/golang/go/issues/31132)) is currently not
   supported, so the action will cause all the goroutines to get activated or
   paused.
10. Function name of the frame.

When the program stops due to exception, panic, or bad access error, the CALL
STACK shows the stop reason and the editor highlights the source location with
more details.



## `dlv` command from DEBUG CONSOLE

DEBUG CONSOLE accepts commands that allow users to dynamically inspect/change
debug configuration, or inspect the list of source code compiled in the debugged
binary. Use `dlv help` and `dlv config -list` from the DEBUG CONSOLE panel to
see the list of supported commands and dynamically adjustable settings.

## Configuration

### Launch.json attributes

There are many attributes that you can adjust in the launch and attach debug
configuration. The following general attributes are mandatory for all launch
configurations.

* `name`: the name of your configuration as it appears in the drop-down in the
  Run view.
* `type`: the debugging type VS Code uses to decide which debugging extension
  should be used. Always leave this set to `"go"`.
* `request`: `launch` or `attach`.

Here is the list of attributes specific to Go debugging.



| Property | Launch | Attach |
| --- | --- | --- |
| `args` | Command line arguments passed to the debugged program.(Default: `[]`) | _n/a_ |
| `asRoot` | (Experimental) Debug with elevated permissions (on Unix). It requires `integrated` or `external` console modes and is ignored in remote debugging.(Default: `false`) | (Experimental) Debug with elevated permissions (on Unix). This requires `integrated` or `external` console modes and is ignored in remote debugging.(Default: `false`) |
| `backend` | Backend used by delve. Maps to `dlv`'s `--backend` flag.Allowed Values: `"default"`, `"native"`, `"lldb"`, `"rr"` | _same as Launch_|
| `buildFlags` | Build flags, to be passed to the Go compiler. Maps to dlv's `--build-flags` flag.(Default: `[]`) | _n/a_ |
| `console` | (Experimental) Where to launch the debugger and the debug target: internal console, integrated terminal, or external terminal. It is ignored in remote debugging.Allowed Values: `"internalConsole"`, `"integratedTerminal"`, `"externalTerminal"`(Default: `internalConsole`) | (Experimental) Where to launch the debugger: internal console, integrated terminal, or external terminal. This does not affect tty of the running program. It is ignored in remote debugging.Allowed Values: `"internalConsole"`, `"integratedTerminal"`, `"externalTerminal"`(Default: `internalConsole`) |
| `coreFilePath` | Path to the core dump file to open. For use on 'core' mode only(Default: `""`) | _n/a_ |
| `cwd` | Workspace relative or absolute path to the working directory of the program being debugged if a non-empty value is specified. The `program` folder is used as the working directory if `cwd` is omitted or empty.(Default: `""`) | Workspace relative or absolute path to the working directory of the program being debugged. Default is the current workspace.(Default: `"${workspaceFolder}"`) |
| `debugAdapter` | Select which debug adapter to use with this launch configuration.Allowed Values: `"legacy"`, `"dlv-dap"`(Default: `dlv-dap`) | _same as Launch_|
| `dlvFlags` | Extra flags for `dlv`. See `dlv help` for the full list of supported. Flags such as `--log-output`, `--log`, `--log-dest`, `--api-version`, `--output`, `--backend` already have corresponding properties in the debug configuration, and flags such as `--listen` and `--headless` are used internally. If they are specified in `dlvFlags`, they may be ignored or cause an error. | _same as Launch_|
| `env` | Environment variables passed to the launched debuggee program. Format as string key:value pairs. Merged with `envFile` and `go.toolsEnvVars` with precedence `env` > `envFile` > `go.toolsEnvVars`. | _n/a_ |
| `envFile` | Absolute path to a file containing environment variable definitions, formatted as string key=value pairs. Multiple files can be specified by provided an array of absolute paths. Merged with `env` and `go.toolsEnvVars` with precedence `env` > `envFile` > `go.toolsEnvVars`.  | _n/a_ |
| `followExec` | (Experimental) Enables or disables follow exec mode.(Default: `false`) | _n/a_ |
| `followExecRegex` | (Experimental) Regular expression. Only child processes with a command line that matches this regular expression will be followed during 'target follow-exec'.(Default: `""`) | _n/a_ |
| `goroutineFilters` | Configures which system goroutines should be shown in the call stack. See https://github.com/go-delve/delve/blob/master/Documentation/cli/README.md#goroutines(Default: `""`) | _same as Launch_|
| `hideSystemGoroutines` | Boolean value to indicate whether system goroutines should be hidden from call stack view.(Default: `false`) | _same as Launch_|
| `host` | When applied to remote-attach configurations, will look for "dlv ... --headless --listen=<host>:" server started externally. In dlv-dap mode this will apply to all other configurations as well. The extension will try to connect to an external server started with "dlv dap --listen=<host>:" to ask it to launch/attach to the target process.(Default: `"127.0.0.1"`) | When applied to remote-attach configurations, will look for "dlv ... --headless --listen=<host>:" server started externally. In dlv-dap mode, this will apply to all other configurations as well. The extension will try to connect to an external server started with "dlv dap --listen=<host>:" to ask it to launch/attach to the target process.(Default: `"127.0.0.1"`) |
| `logDest` | dlv's `--log-dest` flag. See `dlv log` for details. Number argument is not allowed. Supported only in `dlv-dap` mode, and on Linux and Mac OS. | dlv's `--log-dest` flag. See `dlv log` for details. Number argument is not allowed. Supported only in `dlv-dap` mode and on Linux and Mac OS. |
| `logOutput` | Comma separated list of components that should produce debug output. Maps to dlv's `--log-output` flag. Check `dlv log` for details.Allowed Values: `"debugger"`, `"gdbwire"`, `"lldbout"`, `"debuglineerr"`, `"rpc"`, `"dap"`(Default: `"debugger"`) | _same as Launch_|
| `maxArrayValues` | Maximum number of elements read to load an array, slice or map. Only applies when using `dlv-dap` mode.(Default: `64`) | _same as Launch_|
| `maxStringLen` | Maximum number of bytes read to load a string. Longer strings are truncated. Only applies when using `dlv-dap` mode.(Default: `512`) | _same as Launch_|
| `mode` | One of `auto`, `debug`, `test`, `exec`, `replay`, `core`. In `auto` mode, the extension will choose either `debug` or `test` depending on active editor window.Allowed Values: `"auto"`, `"debug"`, `"test"`, `"exec"`, `"replay"`, `"core"`(Default: `auto`) | Indicates local or remote debugging. Local is similar to the `dlv attach` command, remote - to `dlv connect`Allowed Values: `"local"`, `"remote"`(Default: `local`) |
| `output` | Output path for the binary of the debugee.(Default: `"debug"`) | _n/a_ |
| `outputMode` | When set to 'remote' captures the target program's stdout and stderr and transfers it to the client via DAP protocol's output events.Allowed Values: `"local"`, `"remote"`(Default: `local`) | _n/a_ |
| `port` | When applied to remote-attach configurations, will look for "dlv ... --headless --listen=<host>:" server started externally. In dlv-dap mode this will apply to all other configurations as well. The extension will try to connect to an external server started with "dlv dap --listen=<host>:" to ask it to launch/attach to the target process.(Default: `2345`) | When applied to remote-attach configurations, will look for "dlv ... --headless --listen=<host>:" server started externally. In dlv-dap mode, this will apply to all other configurations as well. The extension will try to connect to an external server started with "dlv dap --listen=<host>:" to ask it to launch/attach to the target process.(Default: `2345`) |
| `processId` | _n/a_ | **Option 1:** Use process picker to select a process to attach, or Process ID as integer.Allowed Values: `"${command:pickProcess}"`, `"${command:pickGoProcess}"`**Option 2:** Attach to a process by name. If more than one process matches the name, use the process picker to select a process.**Option 3:** The numeric ID of the process to be debugged. If 0, use the process picker to select a process.(Default: `0`) |
| `program` | Path to the program folder (or any go file within that folder) when in `debug` or `test` mode, and to the pre-built binary file to debug in `exec` mode. If it is not an absolute path, the extension interprets it as a workspace relative path.(Default: `"${workspaceFolder}"`) | _n/a_ |
| `remotePath` | _n/a_ | (Deprecated) *Use `substitutePath` instead.*The path to the source code on the remote machine, when the remote path is different from the local machine. If specified, becomes the first entry in substitutePath. Not supported with `dlv-dap`.(Default: `""`) |
| `showGlobalVariables` | Boolean value to indicate whether global package variables should be shown in the variables pane or not.(Default: `false`) | _same as Launch_|
| `showLog` | Show log output from the delve debugger. Maps to dlv's `--log` flag.(Default: `false`) | _same as Launch_|
| `showPprofLabels` | Configures which pprof lables to show as the goroutine name in the threads view | _same as Launch_|
| `showRegisters` | Boolean value to indicate whether register variables should be shown in the variables pane or not.(Default: `false`) | _same as Launch_|
| `stackTraceDepth` | Maximum depth of stack trace collected from Delve.(Default: `50`) | _same as Launch_|
| `stderrTo` | Writes the program's standard error to a file(Default: `""`) | _n/a_ |
| `stdinFrom` | Reads the program's standard input from a file(Default: `""`) | _n/a_ |
| `stdoutTo` | Writes the program's standard output to a file(Default: `""`) | _n/a_ |
| `stopOnEntry` | Automatically stop program after launch.(Default: `false`) | Automatically stop program after attach.(Default: `false`) |
| `substitutePath` | An array of mappings from a local path (editor) to the remote path (debugee). This setting is useful when working in a file system with symbolic links, running remote debugging, or debugging an executable compiled externally. The debug adapter will replace the local path with the remote path in all of the calls.<li>`"from"`: The absolute local path to be replaced when passing paths to the debugger.(Default: `""`)</li><li>`"to"`: The absolute remote path to be replaced when passing paths back to the client.(Default: `""`)</li> | An array of mappings from a local path (editor) to the remote path (debugee). This setting is useful when working in a file system with symbolic links, running remote debugging, or debugging an executable compiled externally. The debug adapter will replace the local path with the remote path in all of the calls.  Overridden by `remotePath`.<li>`"from"`: The absolute local path to be replaced when passing paths to the debugger.(Default: `""`)</li><li>`"to"`: The absolute remote path to be replaced when passing paths back to the client.(Default: `""`)</li> |
| `trace` | Various levels of logging shown in the debug console & 'Go Debug' output channel. When using the `legacy` debug adapter, the logs will also be written to a file if it is set to a value other than `error`.Allowed Values: `"verbose"`, `"trace"`, `"log"`, `"info"`, `"warn"`, `"error"`(Default: `"error"`) | _same as Launch_|
| `traceDirPath` | Directory in which the record trace is located or to be created for a new output trace. For use on 'replay' mode only(Default: `""`) | _n/a_ |
| `waitFor` | _n/a_ | Wait for a process with a name beginning with the given prefix(Default: `""`) |


⚠️ Delve resolves relative paths from `dlv dap` process's working directory, but
from which directory the extension spawns the `dlv dap` process is an
implementation detail. Thus, use
[the VS Code variables substitution](https://code.visualstudio.com/docs/editor/variables-reference)
to ensure consistent expansion of paths. VS Code will resolve the variables
inside strings in `launch.json` before passing the configuration to the Go
extension and `dlv dap`. For example, `${workspaceFolder}` will be replaced with
the absolute path to the workspace root folder. When appropriate, the Go
extension will resolve relative paths or home directory (~) before sending the
configuration to `dlv dap`.

### Debug symlink directories

Since the debugger and go compiler use the actual filenames, extra configuration
is required to debug symlinked directories. Use the `substitutePath` property to
tell the `debugAdapter` how to properly translate the paths. For example, if
your project lives in `/path/to/actual/helloWorld`, but the project is open in
vscode under the linked folder `/link/to/helloWorld`, you can add the following
to your config to set breakpoints in the files in `/link/to/helloWorld`:

```json
{
    "name": "Launch with symlinks",
    "type": "go",
    "request": "launch",
    "mode": "debug",
    "program": "/path/to/actual/helloWorld",
    "substitutePath": [
        {
            "from": "/link/to/helloWorld",
            "to": "/path/to/actual/helloWorld"
        }
    ]
}
```



### Settings

You can adjust the default value of the following configuration properties using
`go.delveConfig` settings. These default values are useful when you choose to
run a debug session without the launch configuration set in `launch.json`. For
example, debug sessions started using the `Debug Test` code lenses use the
adjusted values from these settings.

* [`go.delveConfig`](settings.md#go.delveConfig)
  * `debugAdapter`: Controls which debug adapter to use (default: `legacy`).
    Select ‘dlv-dap’.
  * `showGlobalVariables`: Show global variables in the Debug view (default:
    `false`).
  * `substitutePath`: Path mappings to apply to get from a path in the editor to
    a path in the compiled program (default: `[]`).

⚠️ Where is the `dlvLoadConfig` setting? Delve debugger imposes variable loading
limits to avoid loading too many variables at once and negatively impacting
debugging latency. The legacy adapter supported `dlvLoadConfig` to adjust these
limits for the duration of the session. The user therefore had to come up with a
one-size-fits-all limit if the default behavior was not satisfactory. `dlv-dap`
mode uses a different approach as described in
[the Data Inspection section](#data-inspection). If this setting is configured
and `dlv-dap` mode is used, the extension will show a warning prompt now. If the
current variable loading behavior and internal limits are not working for you,
please [open an issue](https://github.com/golang/vscode-go/issues/new) and share
your feedback.



## Advanced topics

### Go debug extension architecture overview

VS Code implements a generic, language-agnostic debugger UI based on
[Debug Adapter Protocol](https://microsoft.github.io/debug-adapter-protocol/)
(DAP), an abstract protocol for communicating with debugger backend. Previously,
the Go extension used an intermediary typescript program (legacy debug adapter)
to launch Delve and adapt Delve to DAP. With
[the new, native DAP implementation in Delve](https://github.com/go-delve/delve/tree/master/service/dap),
the intermediary program is no longer necessary, and efficient and tight
integration with Delve becomes possible.



For information on debugging using the legacy debug adapter, please see the old
[Debugging Documentation](debugging.md). Note that many new or enhanced features
discussed in this document may not be available with the legacy debug adapter.

### Handling STDIN

The Go extension and `dlv` started as a subprocess of the extension do not have
access to `tty`. The Go extension captures and forwards STDOUT/STDERR of the
debug program to VS Code, so they can appear in `DEBUG OUTPUT` panel. But this
arrangement does not handle STDIN.

When the target program needs to read from STDIN or access terminals (`tty`),
use the `"console"` launch option that controls where the `dlv` debugger and the
target process run:

* `integratedTerminal` for the terminal inside VS Code
* `externalTerminal` for the terminal outside VS Code

The Go extension delegates interaction with terminals to VS Code
[using Debug Adapter Protocol's `RunInTerminal` functionality](https://github.com/golang/vscode-go/discussions/1626).
For configuring VS Code's terminal related behavior, see VS Code's
[documentation](https://code.visualstudio.com/docs/editor/integrated-terminal).

### Debug programs and tests as root

In order to run and debug a program or a package test running as root, the
debugger (`dlv`) must run with root privilege, too. You can start the debug
session with root privilege utilizing the `"asRoot"` AND `"console"` launch
options. This is currently supported only on Linux and Mac.

When `asRoot` is true, the Go extension will use the `sudo` command to run
`dlv`. Since `sudo` may ask you to enter password, the debug session needs
[terminal access](#handling-stdin) so set `"console": "integratedTerminal"` or
`"console": "externalTerminal"` in the launch configuration.

#### Debug a program as root

For example, the following launch configuration will start `myprogram` and debug
it by running `sudo dlv dap` command in the integrated terminal.

```json
{
    "name": "Launch as Root",
    "request": "launch",
    "mode": "exec",
    "asRoot": true,
    "program": "${workspaceRoot}/myprogram",
    "console": "integratedTerminal",
    ...
}
```

The `asRoot` setting can be used with `auto`/`test`/`debug` launch modes that
**build** the target binary to debug. That means the `go` command will be
invoked as root to compile the binary, too. This can cause issues:

* by default, `sudo` does not preserve the user's current environment variables
  (see documentations about sudo's `--preserve-env` option). For example, `PATH`
  or library paths required for build may be different.
* Go environment variable settings usually associated in the home directory are
  different.
* Module/build caches used during build as root may be different from the caches
  used in your normal build. If they are the same, you may encounter permission
  errors due to cache data written to the caches as root.

Instead, you can arrange the `exec` launch mode to work with a pre-launch
[task](https://code.visualstudio.com/docs/editor/tasks).

First, configure a debug build task to compile the target binary.

In `.vscode/tasks.json`:

```json
{
    ...
    "tasks": [
        {
            "label": "go: build (debug)",
            "type": "shell",
            "command": "go",
            "args": [
                "build",
                "-gcflags=all=-N -l",
                "-o",
                "${fileDirname}/__debug_bin"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            ...
        }
    ]
}
```

The `-gcflags=all=-N -l` flag tells the `go build` command to preserve the debug
information. The `-o` flag causes the compiled binary to be placed in
`"${fileDirname}/__debug_bin"`. Extra build flags and environment variables
_used for build_ should be configured here as `args` or `options`'s `env`
settings.

It might be useful to add `__debug_bin` to your `.gitignore` to avoid debugging
binaries getting checked-in into your repository.

Then, configure the launch config to run the task before starting debugging.

In `.vscode/launch.json`:

```json
    ...
    "configurations": [
        {
            "name": "Launch Package as root",
            "type": "go",
            "request": "launch",
            "mode": "exec",
            "asRoot": true,
            "console": "integratedTerminal",
            "program": "${fileDirname}/__debug_bin",
            "preLaunchTask": "go: build (debug)",
        }
    ]
```

Settings (`args`, `cwd`, `env`, ...) configured in the above `launch.json` will
only apply when _running_ the compiled binary, not when building the binary.

#### Debug a package test as root

To debug package tests as root add the following launch and task configurations.

In `.vscode/tasks.json`:

```json
    ...
    "tasks": [
        {
            ...
        },
        {
            "label": "go test (debug)",
            "type": "shell",
            "command": "go",
            "args": [
                "test",
                "-c",
                "-o",
                "${fileDirname}/__debug_bin"
            ],
            "options": {
                "cwd": "${fileDirname}",
            },
            ...
        }
    ]
```

In `.vscode/launch.json`:

```json
    ...
    "configurations": [
        {
            ...
        },
        {
            "name": "Debug Package Test as root",
            "type": "go",
            "request": "launch",
            "mode": "exec",
            "asRoot": true,
            "program": "${fileDirname}/__debug_bin",
            "cwd": "${fileDirname}",
            "console": "integratedTerminal",
            "preLaunchTask": "go test (debug)"
        }
    ]
```

### Manually install `dlv`

On rare occasions, you may want to install `dlv` by yourself instead of letting
the extension handle its installation.

First, find where the Go extension finds tools. Like
[other tools the extension uses](tools.md#tools), the Go extension searches the
`dlv` executable from `${GOPATH}/bin`, `${GOBIN}` and `${PATH}` (or `Path` in
Windows). So, install `dlv` in the directory. The easiest way to check the tool
installation location the Go extension uses is currently by running the
`Go: Locate Configured Go Tools` command from the command palette (⇧+⌘+P or
Ctrl+Shift+P).

If your Go version is 1.16 or newer:

```
GOBIN=<dir_to_install_dlv> go install github.com/go-delve/delve/cmd/dlv@latest
```

If your Go version is older than 1.16:

```
cd $(mktemp -d)
GO111MODULE=on GOBIN=<dir_to_install_dlv> go get github.com/go-delve/delve/cmd/dlv@latest
```

You can choose to install a different version of `dlv` by specifying a specific
commit hash, a branch name (e.g. `master`), or a released version instead of
`latest`. For more details about manual installation, see
[Delve's documentation](https://github.com/go-delve/delve/tree/master/Documentation/installation).

If you want to explicitly specify the location of the delve binary, use the
`go.alternateTools` setting:

```json5
"go.alternateTools": {
    "dlv": "<absolute path to your dlv binary>"
}
```

### Remote debugging

> If you are able to use the
> [Remote Development](https://aka.ms/vscode-remote/download/extension)
> extensions and VS Code’s universal
> [remote development capabilities](https://code.visualstudio.com/docs/remote/remote-overview),
> that is the recommended way to debug Go programs remotely. Check out
> [Getting started](https://code.visualstudio.com/docs/remote/remote-overview#_getting-started)
> section and
> [Remote tutorials](https://code.visualstudio.com/docs/remote/remote-overview#_remote-tutorials)
> to learn more.

Remote debugging is the debug mode commonly used to work with a debugger and
target running on a remote machine or a container. In spite of its name, it can
also be used on a local machine with server started in an external terminal
(e.g. to support entering stdin into the server's terminal window).

With the introduction of `dlv dap` users now have two options for remote (i.e.
external) debugging.

#### Connect to headless delve with target specified at server start-up

In this mode the user must first manually start a
[`dlv --headless`](https://github.com/go-delve/delve/tree/master/Documentation/api)
server listening at `host:port` while specifying the target program to
debug/test/exec or a process to attach to on the command-line. A
[remote attach](#attach) configuration is then used to connect to the debugger
with a running target.

The
[headless dlv server](https://github.com/go-delve/delve/tree/master/Documentation/api)
can now be used with both `"debugAdapter": "legacy"` (default value) and
`"debugAdapter": "dlv-dap"` (with Delve v1.7.3 or newer) as well as Delve's
[command-line interface](https://github.com/go-delve/delve/tree/master/Documentation/cli)
via `dlv connect`. The `--accept-multiclient` flag makes this a multi-use server
that persists on `Disconnect` from a client and allows repeated connections from
any of the aforementioned clients. A combination of
`--accept-multiclient --continue` flags can be used to resume process execution
on start-up. Please see `dlv --help` and `dlv [command] --help` for dlv's
command-line options.

We encourage you to give the newly added `"debugAdapter": "dlv-dap"` support a
try and to
[let us know of any issues](https://github.com/golang/vscode-go/issues/new). If
you need to use the `legacy` mode, please also see the
[legacy remote debugging](debugging-legacy.md#remote-debugging) documentation.

For example, start external headless server:

```
dlv debug /path/to/program/ --headless --listen=:12345 # also add as needed: --accept-multiclient --continue
```

Connect to it with a remote attach configuration in your `launch.json`:

```json5
{
    "name": "Connect to external session",
    "type": "go",
    "debugAdapter": "dlv-dap", // `legacy` by default
    "request": "attach",
    "mode": "remote",
    "port": 12345,
    "host": "127.0.0.1", // can skip for localhost
    "substitutePath": [
      { "from": "${workspaceFolder}", "to": "/path/to/remote/workspace" },
      ...
  ]
}
```

#### Connect to delve dap with target specified at client start-up

In this mode the user must first manually start a
[`dlv dap` server](https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_dap.md)
listening at `host:port` and then specify the target program via
[launch](#launch) or [attach](#attach) client config with a `"port"` attribute.
Instead of starting a new local server, the Go extension will tell VS Code to
connect to the server specified by `host:port` attributes and then send a
request with the target to debug. This option provides the flexibility of easily
adapting local configurations to connect to external servers, but ⚠️ must be
used with care since anyone who can connect to the server can make it run
arbitrary programs.

When using `launch` mode, the `program` attribute must point to the absolute
path of the package or binary to debug in the remote host’s file system even
when `substitutePath` is specified. When using `attach` mode outside of local
host, you need to specify the `processId` in the config since
[the processId resolution feature](#attach) cannot gather information about
processes running remotely.



Start a `dlv dap` server ready to accept a client request to launch or attach to
a target process:

```
dlv dap --listen=:12345
```

Use the following `launch` configuration to tell `dlv` to execute a binary
precompiled with `go build -gcflags=all="-N -l"`:

```json5
{
  "name": "Connect and launch",
  "type": "go",
  "debugAdapter": "dlv-dap", // the default
  "request": "launch",
  "port": 12345,
  "host": "127.0.0.1", // can skip for localhost
  "mode": "exec",
  "program": "/absolute/path/to/remote/workspace/program/executable",
  "substitutePath": [
      { "from": "${workspaceFolder}", "to": "/path/to/remote/workspace" },
      ...
  ]
}
```

Or have the binary compiled by `dlv dap` by modifying the above configuration to
use:

```json5
  "mode": "debug",
  "program": "/absolute/path/to/remote/workspace/package",
```

⚠️ Limitations

* Unlike `dlv --headless` above, `dlv dap` does not support
  `--accept-multiclient` or `--continue` flags, which means after a debug
  session ends, the `dlv dap` process will always exit.
* If you use `debug` or `test` mode `launch` requests, Delve builds the target
  binary. Delve tries to build the target from the directory where the `dlv`
  process is running, so make sure to run the `dlv` command from the directory
  you would run the `go build` or `go test` command.

### Run debugee externally

Sometimes you might like to launch the program for debugging outside of VS Code
(e.g. as a workaround of the missing `console` support to enter stdin via an
external terminal or separate target's output from debug session logging). There
are currently two options:

* Compile and run the target program from the external terminal and use
  [the "attach" configuration](#attach).
* Run the debug server from the external terminal with `--listen=:` and
  have VS Code connect to it using `port` in your launch configuration (see
  ["Remote Debugging"](#remote-debugging) for more details)

## Troubleshooting

The suggestions below are intended to help you troubleshoot any problems you
encounter. If you are unable to resolve the issue, please take a look at the
[current known debugging issues](https://github.com/golang/vscode-go/issues?q=is%3Aissue+is%3Aopen+label%3ADebug)
or [report a new issue](#reporting-issues).

1. Read documentation and [FAQs](#faqs). Also check the
   [Delve FAQ](https://github.com/go-delve/delve/blob/master/Documentation/faq.md)
   in case the problem is mentioned there.
1. Check your `launch.json` configuration. Often error messages appearing in the
   DEBUG CONSOLE panel reveal issues.
1. Update Delve (`dlv`) to pick up most recent bug fixes. Follow
   [the instruction](debugging.md#staying-up-to-date).
1. Check if you can reproduce the issue with `dlv`, the command line tool from
   the integrated terminal.  If it's reproducible when
   using `dlv`, take a look at the
   [Delve project issue tracker](https://github.com/go-delve/delve/issues).
1. Capture [logs](debugging.md#collecting-logs) and inspect them.
1. Look at the
   [existing debugging issues](https://github.com/golang/vscode-go/labels/Debug)
   if similar issues were reported.
1. If none of these solve your problem, please
   [open a new issue](#reporting-issues).

## FAQs

### I need to view large strings. How can I do that if `dlvLoadConfig` with `maxStringLen` is deprecated?

The legacy adapter used `dlvLoadConfig` as one-time session-wide setting to
override dlv's conservative default variable loading limits, intended to protect
tool's performance. The new debug adapter is taking a different approach with
on-demand loading of composite data and updated string limits, relaxed when
interacting with individual strings. In particular, if the new default limit of
512, applied to all string values in the variables pane, is not sufficient, you
can take advantage of a larger limit of 4096 with one of the following:

* Hover over the variable in the source code
* `Copy as Expression` to query the string via REPL in the DEBUG CONSOLE panel
* `Copy Value` to clipboard

Please [open an issue](https://github.com/golang/vscode-go/issues/new) if this
is not sufficient for your use case or if you have any additional feedback.

### Why does my debug session have an `invalid command` error when I try to step?

When stepping through a program on a particular goroutine, the debugger will
make sure that the step is completed, even when interrupted by events on a
different goroutine. If a breakpoint is hit on a different goroutine, the debug
adapter will stop the program execution to allow you to inspect the state, even
though the step request is still active.

If you attempt to make another step request you will get an `invalid command`
error.



Use `Continue` to resume program execution.

If you do not want the step request to be interrupted, you can disable all
breakpoints from VS Code from the context menu in the `Breakpoints` view.



### My program does not stop at breakpoints

Check the "BREAKPOINTS" section in the debug view and see if the breakpoints are
[greyed out](https://code.visualstudio.com/docs/editor/debugging#_breakpoints)
when your debug session is active. Setting `stopOnEntry` is a great way to pause
execution at the start to _verify_ breakpoints are set correctly. Or
[enable logging](#collecting-logs) and see if `setBreakpoints` requests
succeeded with all the breakpoints _verified_.

This problem often occurs when the source location used in compiling the
debugged program and the workspace directory VS Code uses are different. Common
culprits are remote debugging where the program is built in the remote location,
use of symbolic links, or use of `-trimpath` build flags. In this case,
configure the `substitutePath` attribute in your launch configuration.

#### Trimpath tips

If you are using `-trimpath` to build your program, you need to add entries to substitute
path to let the debugger know how to map the package paths that are compiled in the
binary to the files that you are looking at in the editor.

Here are some tips for configuring substitutePath. This assumes that your program is using module mode, which is the default.

One rule that you will need will map your main module. The mapping will map `"from"` the file path to the directory containing the module, `"to"` the module path.

You will also need to create a similar mapping for all dependencies. These include modules
in the module cache, vendored modules, and the standard library.

```json
"substitutePath": [
  // Main module.
  {
   "from": "${workspaceFolder}",
   "to": "moduleName",
  },
  // Module cache paths.
  {
   "from": "${env:HOME}/go/pkg/mod/github.com",
   "to": "github.com",
  },
  {
   "from": "${env:HOME}/go/pkg/mod/golang.org",
   "to": "golang.org",
  },
  ...
  // Standard library paths.
  // This rule should come last since the empty "to" will match every path.
  { "from": "/path/to/local/goroot/pkg" , "to": ""}
 ],
```

Since rules are applied both from client to server and server to client,
rules with an empty string will be applied to _all_ paths that it sees, so even
dependencies will be mapped to `"/path/to/module"`.

We plan to make this easier in the future. Progress can be tracked
in the issue tracker [golang/vscode-go#1985](https://github.com/golang/vscode-go/issues/1985).

### Debug sessions started with the "debug test" CodeLens or the test UI does not use my `launch.json` configuration

The "debug test" CodeLens and the [test UI](features.md#test-and-benchmark) do
not use the `launch.json` configuration
([Issue 855](https://github.com/golang/vscode-go/issues/855)). As a workaround,
use the `go.delveConfig` setting and the `go.testFlags` setting. Please note
that these all apply to all debug sessions unless overwritten by a specific
`launch.json` configuration.

### Starting a debug session fails with

`decoding dwarf section info at offset 0x0: too short` or
`could not open debug info` error

These errors indicate that your binary was built with linker flags that stripped
the symbol table (`-s`) or the DWARF debug information (`-w`), making debugging
impossible. If the binary is built while launching the session, make sure your
`launch.json` configuration does not contain
`"buildFlags": "--ldflags '-s -w'"`. If you use `debug test` or Test Explorer,
check `go.buildFlags` in `settings.json`. If the binary is built externally,
check the command-line flags and do not use `go run`. Unlike `go build`,
`go run` passes `-s -w` to the linker under the hood. If you try to attach to
such a binary with a debugger, it will fail with one of the above errors (see Go
Issue [24833](https://github.com/golang/go/issues/24833)). Instead let dlv build
the binary for you or use `go build -gcflags=all="-N -l"`.

## Report issues

When you are having issues in `dlv-dap` mode, first check if the problems are
reproducible after updating `dlv` and using the most recent version of `dlv`.
It's possible that the problems are already fixed. You can also try to install
`dlv` at tree head. Follow the instruction for
[updating `dlv`](#staying-up-to-date) and
[updating extension](https://code.visualstudio.com/docs/editor/extension-gallery#\_extension-autoupdate).

Please report issues in
[our issue tracker](https://github.com/golang/vscode-go/issues) with the
following information.

* `go version`
* `go version -m `
* VS Code and VS Code Go version (e.g. `code --version`)
* Instructions to reproduce the issue (code snippets, your `launch.json`, screenshot)
* DAP trace (See [the instruction](#collecting-logs))

### Collect logs

```json5
{
    "name": "Launch file",
    "type": "go",
    "trace": "verbose",
    "showLog": true,
    "logOutput": "dap",
    ...
}
```

The `logOutput` and `showLog` attributes in `launch.json` enable Delve-side
logging (server-side) and DAP message tracing. The `trace` attribute controls
the verbosity of Go extension's side logging (client-side).

The logging will appear in the `Go Debug` output channel (Command Palette ->
"View: Toggle Output" -> Select "Go Debug" from the dropdown menu). By nature,
debug logs may contain sensitive information. Please review the logs carefully
before sharing debug logs.

## Development

### Code location

The core part of Delve DAP implementation is in the
[`service/dap`](https://github.com/go-delve/delve/tree/master/service/dap)
package. Follow Delve project's
[contribution guideline](https://github.com/go-delve/delve/blob/master/CONTRIBUTING.md#contributing-code)
to send PRs.

Code for integration with the Go extension is mostly in
[`src/goDebugFactory.ts`](https://github.com/golang/vscode-go/blob/master/extension/src/goDebugFactory.ts)
and tests are in
[`test/integration/goDebug.test.ts`](https://github.com/golang/vscode-go/blob/master/extension/test/integration/goDebug.test.ts).
Please take a look at VS Code Go project's
[contribution guideline](contributing.md) to learn about how to prepare a change
and send it for review.

### Testing

For simple launch cases, build the `dlv` binary, and configure
`"go.alternateTools"` setting.

```json5
"go.alternateTools": {
    "dlv": 
}
```

 If you are having issues with seeing logs and/or
suspect problems in the extension's integration, you can start the Delve DAP
server from a separate terminal and configure the extension to directly connect
to it. Please remember to
[file an issue](https://github.com/golang/vscode-go/issues/new) if you encounter
any logging-related problems.

```
dlv dap --listen=:12345 --log --log-output=dap
```

```json5
{
    "name": "Launch file",
    "type": "go",
    "request": "launch",
    "debugAdapter": "dlv-dap",
    ...
    "port": 12345
}
```

---

## File: docs/debugging-legacy.md

# Debugging with Legacy Debug Adapter

The Go extension historically used a small adapter program to work with the Go debugger, [Delve].
The extension transitioned to communicate with [Delve] directly but there are still cases you may
need to use the legacy debug adapter (e.g. remote debugging). This document explains how to use the
***legacy*** debug adapter.


* [Set up](#set-up)
  * [Installation](#installation)
  * [Configuration](#configuration)
* [Launch Configurations](#launch-configurations)
  * [Specifying build tags](#specifying-build-tags)
  * [Specifying other build flags](#specifying-other-build-flags)
  * [Using VS Code Variables](#using-vs-code-variables)
  * [Snippets](#snippets)
* [Debugging on Windows Subsystem for Linux (WSL)](#debugging-on-windows-subsystem-for-linux-wsl)
* [Remote Debugging](#remote-debugging)
* [Troubleshooting](#troubleshooting)
  * [Read documentation and common issues](#read-documentation-and-common-issues)
  * [Update Delve](#update-delve)
  * [Check for multiple versions of Delve](#check-for-multiple-versions-of-delve)
  * [Check your launch configuration](#check-your-launch-configuration)
  * [Check your GOPATH](#check-your-gopath)
  * [Enable logging](#enable-logging)
  * [Optional: Debug the debugger](#optional-debug-the-debugger)
  * [Ask for help](#ask-for-help)
* [Common issues](#common-issues)

## Set up

[Delve] (`dlv`) should be installed by default when you install this extension.
You may need to update `dlv` to the latest version to support the latest version
of Go. To install or update `dlv`, open the [Command Palette][]
(Windows/Linux: Ctrl+Shift+P; OSX: Shift+Command+P), select [`Go: Install/Update Tools`](settings.md#go-installupdate-tools), and select [`dlv`](tools.md#dlv).

## Selecting `legacy` debug adapter

To opt in to use the legacy debug adapter (`legacy`) by default, add the following in your VSCode settings.json.

```
    "go.delveConfig": {
        "debugAdapter": "legacy",
    }
```

If you want to use the legacy mode for only a subset of your launch configurations, you can use [the `debugAdapter` attribute](#launchjson-attributes) to switch between `"dlv-dap"` and `"legacy"` mode.
For [Remote Debugging](#remote-debugging) (launch configuration with `"mode": "remote"` attribute),
the extension will use the `"legacy"` mode by default, so setting this attribute won't be necessary.

Throughout this document, we assume that you opted in to use the legacy debug adapter.
For debugging using the new debug adapter (default, `"dlv-dap"` mode), please see the documentation about [Debugging](https://github.com/golang/vscode-go/tree/master/docs/debugging-legacy.md).

### Configuration

You may not need to configure any settings to start debugging your programs, but you should be aware that the debugger looks at the following settings.

* Related to [`GOPATH`](gopath.md):
  * [`go.gopath`](settings.md#go.gopath)
  * [`go.inferGopath`](settings.md#go.inferGopath)
* [`go.delveConfig`](settings.md#go.delveConfig)
  * `apiVersion`: Controls the version of the Delve API used (default: `2`).
  * `dlvLoadConfig`: The configuration passed to Delve, which controls how variables are shown in the Debug pane. Not applicable when `apiVersion` is 1.
    * `maxStringLen`: Maximum number of bytes read from a string (default: `64`).
    * `maxArrayValues`: Maximum number of elements read from an array, slice, or map (default: `64`).
    * `maxStructFields`: Maximum number of fields read from a struct. A setting of `-1` indicates that all fields should be read (default: `-1`).
    * `maxVariableRecurse`: How far to recurse when evaluating nested types (default: `1`).
    * `followPointers`: Automatically dereference pointers (default: `true`).
  * `showGlobalVariables`: Show global variables in the Debug view (default: `false`).
  * `debugAdapter`: Controls which debug adapter to use (default: `legacy`).
  * `substitutePath`: Path mappings to apply to get from a path in the editor to a path in the compiled program (default: `[]`).

There are some common cases when you might want to tweak the Delve configurations.

* To change the default cap of 64 on string and array length when inspecting variables in the Debug view, set `maxStringLen`. (See a related known issue: [golang/vscode-go#126](https://github.com/golang/vscode-go/issues/126)).
* To evaluate nested variables in the Run view, set `maxVariableRecurse`.

## Launch Configurations

To get started debugging, run the command `Debug: Open launch.json`. If you did not already have a `launch.json` file for your project, this will create one for you. It will contain this default configuration, which can be used to debug the current package. With mode `auto`, the file that is currently open will determine whether to debug the program as a test. If `program` is instead set to a Go file, that file will determine which mode to run in.

```json5
{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch",
            "type": "go",
            "request": "launch",
            "mode": "auto",
            "program": "${fileDirname}",
            "debugAdapter": "legacy",
            "env": {},
            "args": []
        }
    ]
}
```

There are some more properties that you can adjust in the debug configuration:

Property   | Description
--------   | -----------
name       | The name for your configuration as it appears in the drop-down in the Run view.
type       | Always leave this set to `"go"`. VS Code uses this setting to determine which extension should be used for debugging.
request    | One of `launch` or `attach`. Use `attach` when you want to attach to a running process.
mode       | For `launch` requests, one of `auto`, `debug`, `remote`, `test`, or `exec`. For `attach` requests, use `local` or `remote`.
program    | In `test` or `debug` mode, this refers to the absolute path to the package or file to debug. In `exec` mode, this is the existing binary file to debug. Not applicable to `attach` requests.
env        | Environment variables to use when debugging. Use the format: `{ "NAME": "VALUE" }`. Not applicable to `attach` requests.
envFile    | Absolute path to a file containing environment variable definitions. The environment variables passed in via the `env` property override the ones in this file.
args       | Array of command-line arguments to pass to the program being debugged.
showLog    | If `true` and `logDest` is not set, Delve logs will be printed in the Debug Console panel. If `true` and `logDest` is set, logs will be written to the `logDest` file. This corresponds to `dlv`'s `--log` flag.
logOutput  | Comma-separated list of Delve components (`debugger`, `gdbwire`, `lldbout`, `debuglineerr`, `rpc`) that should produce debug output when `showLog` is `true`. This corresponds to `dlv`'s `--log-output` flag.
logDest    | Absolute path to the delve log output file. This corresponds to `dlv`'s `--log-dest` flag, but number (used for file descriptor) is disallowed. Supported only in dlv-dap mode on Linux and Mac.
buildFlags | Build flags to pass to the Go compiler. This corresponds to `dlv`'s `--build-flags` flag.
dlvFlags   | Extra flags passed to `dlv`. See `dlv help` for the full list of supported flags. This is useful when users need to pass less commonly used or new flags such as `--only-same-user`, `--check-go-version`. Note that some flags such as `--log-output`, `--log`, `--log-dest`, `--api-version` already have corresponding properties in the debug configuration, and flags such as `--listen` and `--headless` are used internally. If they are specified in `dlvFlags`, they may be ignored or cause an error.
remotePath | If remote debugging (`mode`: `remote`), this should be the absolute path to the package being debugged on the remote machine. See the section on [Remote Debugging](#remote-debugging) for further details. [golang/vscode-go#45](https://github.com/golang/vscode-go/issues/45) is also relevant. Becomes the first mapping in substitutePath.
substitutePath | An array of mappings from an absolute local path to an absolute remote path that is used by the debuggee. The debug adapter will replace the local path with the remote path in all of the calls. The mappings are applied in order, and the first matching mapping is used. This can be used to map files that have moved since the program was built, different remote paths, and symlinked files or directories. This is intended to be equivalent to the [substitute-path](https://github.com/go-delve/delve/tree/master/Documentation/cli#config) configuration, and will eventually configure substitute-path in Delve directly.
cwd | The working directory to be used in running the program. If remote debugging (`mode`: `remote`), this should be the absolute path to the working directory being debugged on the local machine. The extension defaults to the workspace folder, or the workspace folder of the open file in multi root workspaces. See the section on [Remote Debugging](#remote-debugging) for further details. [golang/vscode-go#45](https://github.com/golang/vscode-go/issues/45) is also relevant.
processId  | This is the process ID of the executable you want to debug. Applicable only when using the `attach` request in `local` mode. By setting this to the command name of the process, `${command:pickProcess}`, or`${command:pickGoProcess}` a quick pick menu will show a list of processes to choose from.

### Specifying [build tags](https://golang.org/pkg/go/build/#hdr-Build_Constraints)

If your program contains [build tags](https://golang.org/pkg/go/build/#hdr-Build_Constraints), you can use the `buildFlags` property. For example, if you build your code with:

```bash
go build -tags=whatever
```

Then, set:

```json5
"buildFlags": "-tags=whatever"
```

in your launch configuration. This property supports multiple tags, which you can set by using single quotes. For example:

```json5
"buildFlags": "-tags='first,second,third'"
```



### Specifying other build flags

The flags specified in `buildFlags` and `env.GOFLAGS` are passed to the Go compiler when building your program for debugging. Delve adds `-gcflags=all="-N -l"` to the list of build flags to disable optimizations. User specified buildFlags conflict with this setting, so the extension removes them ([Issue #117](https://github.com/golang/vscode-go/issues/117)). If you wish to debug a program using custom `-gcflags`, build the program using `go build` and launch using `exec` mode:

```json
{
    "name": "Launch executable",
    "type": "go",
    "request": "launch",
    "mode": "exec",
    "program": "/absolute/path/to/executable"
}
```

Note that it is not recommended to debug optimized executables as Delve may not have the information necessary to properly debug your program.

### Using [VS Code variables]

Any property in the launch configuration that requires a file path can be specified in terms of [VS Code variables]. Here are some useful ones to know:

* `${workspaceFolder}` refers to the root of the workspace opened in VS Code. If using a multi root workspace, you must specify the folder name `${workspaceFolder:folderName}`
* `${fileWorkspaceFolder}` refers to the the current opened file's workspace folder.
* `${file}` refers to the currently opened file.
* `${fileDirname}` refers to the directory containing the currently opened file. This is typically also the name of the Go package containing this file, and as such, can be used to debug the currently opened package.

### Snippets

In addition to [VS Code variables], you can make use of [snippets] when editing the launch configuration in `launch.json`.

When you type `go` in the `launch.json` file, you will see snippet suggestions for debugging the current file or package or a given test function.

Below are the available sample configurations:

#### Debug the current file (`Go: Launch file`)

Recall that `${file}` refers to the currently opened file (see [Using VS Code Variables](#using-vs-code-variables)). For debugging a package that consists with multiple files, use `${fileDirname}` instead.

```json5
{
    "name": "Launch file",
    "type": "go",
    "request": "launch",
    "mode": "auto",
    "program": "${file}"
}
```

#### Debug a single test function (`Go: Launch test function`)

Recall that `${workspaceFolder}` refers to the current workspace (see [Using VS Code Variables](#using-vs-code-variables)). You will need to manually specify the function name instead of `"MyTestFunction"`.

```json5
{
    "name": "Launch test function",
    "type": "go",
    "request": "launch",
    "mode": "test",
    "program": "${workspaceFolder}",
    "args": [
        "-test.run",
        "MyTestFunction"
    ]
}
```

#### Debug all tests in the given package (`Go: Launch test package`)

A package is a collection of source files in the same directory that are compiled together.
Recall that `${fileDirname}` refers to the directory of the open file (see [Using VS Code Variables](#using-vs-code-variables)).

```json5
{
    "name": "Launch test package",
    "type": "go",
    "request": "launch",
    "mode": "test",
    "program": "${workspaceFolder}"
}
```

#### Attach to a running local process via its process ID (`Go: Attach to local process`)

Substitute `processName` with the name of the local process.

```json5
{
    "name": "Attach to local process",
    "type": "go",
    "request": "attach",
    "mode": "local",
    "processId": "processName"
}
```

#### Attach to a running server (`Go: Connect to Server`)

```json5
{
    "name": "Connect to server",
    "type": "go",
    "request": "attach",
    "mode": "remote",
    "remotePath": "${workspaceFolder}",
    "port": 2345,
    "host": "127.0.0.1"
}
```

#### Debug an existing binary

There is no snippet suggestion for this configuration.

```json
{
    "name": "Launch executable",
    "type": "go",
    "request": "launch",
    "mode": "exec",
    "program": "/absolute/path/to/executable"
}
```

If passing arguments to or calling subcommands and flags from a binary, the `args` property can be used.

```json
{
    "name": "Launch executable",
    "type": "go",
    "request": "launch",
    "mode": "exec",
    "program": "/absolute/path/to/executable",
    "args": ["subcommand", "arg", "--flag"],
}
```

## Debugging on [Windows Subsystem for Linux (WSL)](https://docs.microsoft.com/en-us/windows/wsl/)

If you are using using WSL, you will need the WSL 2 Linux kernel.  See [WSL 2 Installation](https://docs.microsoft.com/en-us/windows/wsl/wsl2-install) and note the Window 10 build version requirements.

## Remote Debugging



To debug on a remote machine, you must first run a headless Delve server on the target machine. The examples below assume that you are in the same folder as the package you want to debug. If not, please refer to the [`dlv debug` documentation](https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_debug.md).

To start the headless Delve server:

```bash
dlv debug --headless --listen=:2345 --log --api-version=2
```

Any arguments that you want to pass to the program you are debugging must also be passed to this Delve server. For example:

```bash
dlv debug --headless --listen=:2345 --log -- -myArg=123
```

Then, create a remote debug configuration in your `launch.json`.

```json5
{
    "name": "Launch remote",
    "type": "go",
    "request": "attach",
    "mode": "remote",
    "remotePath": "/absolute/path/dir/on/remote/machine",
    "port": 2345,
    "host": "127.0.0.1",
    "cwd": "/absolute/path/dir/on/local/machine",
}
```

In the example, the VS Code debugger will run on the same machine as the headless `dlv` server. Make sure to update the `port` and `host` settings to point to your remote machine.

`remotePath` should point to the absolute path of the program being debugged in the remote machine. `cwd` should point to the absolute path of the working directory of the program being debugged on your local machine. This should be the counterpart of the folder in `remotePath`. See [golang/vscode-go#45](https://github.com/golang/vscode-go/issues/45) for updates regarding `remotePath` and `cwd`. You can also use the equivalent `substitutePath` configuration.

```json5
{
    "name": "Launch remote",
    "type": "go",
    "request": "attach",
    "mode": "remote",
    "substitutePath": [
		{
			"from": "/absolute/path/dir/on/local/machine",
			"to": "/absolute/path/dir/on/remote/machine",
		},
	],
    "port": 2345,
    "host": "127.0.0.1",
    "cwd": "/absolute/path/dir/on/local/machine",
}
```

If you do not set, `remotePath` or `substitutePath`, then the debug adapter will attempt to infer the path mappings. See [golang/vscode-go#45](https://github.com/golang/vscode-go/issues/45) for more information.

When you run the `Launch remote` target, VS Code will send debugging commands to the `dlv` server you started, instead of launching it's own `dlv` instance against your program.

For further examples, see [this launch configuration for a process running in a Docker host](https://github.com/lukehoban/webapp-go/tree/debugging).

## Troubleshooting

Debugging is one of the most complex features offered by this extension. The features are not complete, and a new implementation is currently being developed (see [golang/vscode-go#23](https://github.com/golang/vscode-go/issues/23)).

The suggestions below are intended to help you troubleshoot any problems you encounter. If you are unable to resolve the issue, please take a look at the [current known debugging issues](https://github.com/golang/vscode-go/issues?q=is%3Aissue+is%3Aopen+label%3Adebug) or [file a new issue](https://github.com/golang/vscode-go/issues/new/choose).

### Read documentation and [common issues](#common-issues)

Start by taking a quick glance at the [common issues](#common-issues) described below. You can also check the [Delve FAQ](https://github.com/go-delve/delve/blob/master/Documentation/faq.md) in case the problem is mentioned there.

### Update Delve

If the problem persists, it's time to start troubleshooting. A good first step is to make sure that you are working with the latest version of Delve. You can do this by running the [`Go: Install/Update Tools`](settings.md#go-installupdate-tools) command and selecting [`dlv`](tools.md#dlv).

### Check your [launch configuration](#launch-configurations)

Next, confirm that your [launch configuration](#launch-configurations) is correct.

One common error is `could not launch process: stat ***/debug.test: no such file or directory`. You may see this while running in the `test` mode. This happens when the `program` attribute points to a folder with no test files, so ensure that the `program` attribute points to a directory containing the test files you wish to debug.

Also, check the version of the Delve API used in your [launch configuration](#launch-configurations). This is handled by the `–api-version` flag, `2` is the default. If you are debugging on a remote machine, this is particularly important, as the versions on the local and remote machines much match. You can change the API version by editing the [`launch.json` file](#launch-configurations).

### Check for multiple versions of Delve

You might have multiple different versions of [`dlv`](tools.md#dlv) installed, and VS Code Go could be using a wrong or old version. Run the [`Go: Locate Configured Go Tools`](settings.md#go-locate-configured-go-tools) command and see where VS Code Go has found `dlv` on your machine. You can try running `which dlv` to see which version of `dlv` you are using on the [command-line](https://github.com/go-delve/delve/tree/master/Documentation/cli).

To fix the issue, simply delete the version of `dlv` used by the Go extension. Note that the extension first searches for binaries in your `$GOPATH/bin` and then looks on your `$PATH`.

If you see the error message `Failed to continue: "Error: spawn EACCES"`, the issue is probably multiple versions of `dlv`.

### Try building your binary **without** compiler optimizations

If you notice `Unverified breakpoints` or missing variables, ensure that your binary was built **without** compiler optimizations. Try building the binary with `-gcflags="all=-N -l"`.

### Check your `GOPATH`

Make sure that the debugger is using the right [`GOPATH`](gopath.md). This is probably the issue if you see `Cannot find package ".." in any of ...` errors. Read more about configuring your [GOPATH](gopath.md) or [file an issue report](https://github.com/golang/vscode-go/issues/new/choose).

**As a work-around**, add the correct `GOPATH` as an environment variable in the `env` property in the `launch.json` file.

### Enable logging

Next, check the logs produced by Delve. These will need to be manually enabled. Follow these steps:

* Set `"showLog": true` in your launch configuration. This will show Delve logs in the Debug Console pane (Ctrl+Shift+Y).
* Set `"trace": "log"` in your launch configuration. Again, you will see logs in the Debug Console pane (Ctrl+Shift+Y). These logs will also be saved to a file and the path to this file will be printed at the top of the Debug Console.
* Set `"logOutput": "rpc"` in your launch configuration. You will see logs of the RPC messages going between VS Code and Delve. Note that for this to work, you must also have set `"showLog": true`.
  * The `logOutput` attribute corresponds to the `--log-output` flag used by Delve. It is a comma-separated list of components that should produce debug output.

See [common issues](#common-issues) below to decipher error messages you may find in your logs.

With `"trace": "log"`, you will see the actual call being made to `dlv`. To aid in your investigation, you can copy that and run it in your terminal.

### **Optional**: Debug the debugger

This is not a required step, but if you want to continue digging deeper, you can, in fact, debug the debugger. The code for the debugger can be found in the [debug adapter module](../src/debugAdapter). See our [contribution guide](contributing.md) to learn how to [run](contributing.md#run) and [sideload](contributing.md#sideload) the Go extension.

### Ask for help

At this point, it's time to look at the [common issues](#common-issues) below or the [existing debugging issues](https://github.com/golang/vscode-go/issues?q=is%3Aissue+is%3Aopen+label%3Adebug) on the [issue tracker](https://github.com/golang/vscode-go/issues). If that still doesn't solve your problem, [file a new issue](https://github.com/golang/vscode-go/issues/new/choose).

## Common Issues

### delve/launch hangs with no messages on WSL

Try running ```delve debug ./main``` in the WSL command line and see if you get a prompt.

**_Solution_**: Ensure you are running the WSL 2 Kernel, which (as of 4/15/2020) requires an early release of the Windows 10 OS. This is available to anyone via the Windows Insider program. See [Debugging on WSL](#debugging-on-windows-subsystem-for-linux-wsl).

### could not launch process: could not fork/exec

The solution this issue differs based on your OS.

#### OSX

This usually happens on OSX due to signing issues. See the discussions in [Microsoft/vscode-go#717](https://github.com/Microsoft/vscode-go/issues/717), [Microsoft/vscode-go#269](https://github.com/Microsoft/vscode-go/issues/269) and [go-delve/delve#357](https://github.com/go-delve/delve/issues/357).

**_Solution_**: You may have to uninstall dlv and install it manually as described in the [Delve instructions](https://github.com/go-delve/delve/blob/master/Documentation/installation/osx/install.md#manual-install).

#### Linux/Docker

Docker has security settings preventing `ptrace(2)` operations by default within the container.

**_Solution_**: To run your container insecurely, pass `--security-opt=seccomp:unconfined` to `docker run`. See [go-delve/delve#515](https://github.com/go-delve/delve/issues/515) for references.

#### could not launch process: exec: "lldb-server": executable file not found in $PATH

This error can show up for Mac users using Delve versions 0.12.2 and above. `xcode-select --install` has solved the problem for a number of users.

### Debugging symlink directories

Since the debugger and go compiler use the actual filenames, extra configuration is required to debug symlinked directories. Use the `substitutePath` property to tell the debugAdapter how to properly translate the paths. For example, if your project lives in `/path/to/actual/helloWorld`, but the project is open in vscode under the linked folder `/path/to/hello`, you can add the following to your config to set breakpoints in the files in `/path/to/hello`:

```json5
{
    "name": "Launch remote",
    "type": "go",
    "request": "launch",
    "mode": "debug",
    "program": "/path/to/hello",
    "substitutePath": [
		{
			"from": "/path/to/hello",
			"to": "/path/to/actual/helloWorld",
		},
	],
}
```

This extension does not provide general support for debugging projects containing symlinks. If `substitutePath` does not meet your needs, please consider commenting on this issue that contains updates to symlink support reference [golang/vscode-go#622](https://github.com/golang/vscode-go/issues/622).

[Delve]: https://github.com/go-delve/delve
[VS Code variables]: https://code.visualstudio.com/docs/editor/variables-reference
[snippets]: https://code.visualstudio.com/docs/editor/userdefinedsnippets
[Command Palette]: https://code.visualstudio.com/docs/getstarted/userinterface#_command-palette

---

## File: docs/experiments.md

# Experiments

Pre-release versions of [vscode-go][vscode-go] include experimental features.
These features may be individually enabled or disabled via the setting
`go.experiments`.

[vscode-go]: https://github.com/golang/vscode-go/blob/master/README.md#pre-release-versions

## Test explorer

[Go Companion][exp-vscode-go] includes an experimental test explorer
implementation based on `gopls`'s test discovery. This requires gopls v0.17.0 or
newer. If Go Companion is present and vscode-go is a pre-release version,
vscode-go will prefer Go Companion's test explorer, disabling its own, unless
the experiment is set to `off`. The experimental test explorer provides more
robust test discovery by using gopls, including static discovery of _some_
subtests. It also implements:

- Ignore tests within files excluded by `files.exclude` or
  `goExp.testExplorer.exclude`.
- Disable automatic discovery of tests by setting `goExp.testExplorer.discovery`
  to "off".
- Control how tests are displayed with `goExp.testExplorer.showFiles`,
  `goExp.testExplorer.nestPackages`, and `goExp.testExplorer.nestSubtests`.
- Debugging a test updates its status in the test explorer.
- Support for continuous runs.
- Support for code coverage.
- Code lenses (hidden by default) that are integrated with the test explorer.
- Integrated viewer for pprof profiles.

[exp-vscode-go]: https://marketplace.visualstudio.com/items?itemName=ethan-reesor.exp-vscode-go

---

## File: docs/faq.md

# Frequently Asked Questions

**NOTE: [Debugging](debugging.md#faqs) has its own FAQ documentation.**

## Syntax highlighting doesn't seem to work.

The default syntax highlighting for Go files is provided by a
[TextMate rule](https://github.com/worlpaker/go-syntax) embedded in VS Code,
not by this extension.

For accurate syntax highlighting (including generics support), we recommend enabling
[semantic highlighting](https://code.visualstudio.com/api/language-extensions/semantic-highlight-guide)
by turning on [Gopls' `ui.semanticTokens` setting](settings.md#uisemantictokens).

```json
"gopls": { "ui.semanticTokens": true }
```

If you are experiencing issues with syntax highlighting, first check if you
are using semantic highlighting. In case you did not enable semantic highlighting,
report the issues to the [go-syntax](https://github.com/worlpaker/go-syntax)
project directly.

## Code formatting by this extension doesn't seem to work.

When you have multiple formatter extensions, be sure to set this
extension as the default formatter for go language.
```json5
"[go]": {
  "editor.defaultFormatter": "golang.go"
}
```

## How can I stop the extension from formatting files on save?

Formatting and organizing imports for Go are enabled by default. This is implemented
by setting the [language-specific editor settings](https://code.visualstudio.com/docs/getstarted/settings#_languagespecific-editor-settings), that take precedence
over user/workspace editor settings.

You can choose to disable them by configuring the following settings.

```json5
"[go]": {
        "editor.formatOnSave": false,
        "editor.codeActionsOnSave": {
            "source.organizeImports": false
        }
}
```

This decision was made a while ago to help users follow the best practice,
and to detect broken code early (e.g. unused imports causes compile errors in Go).
Unfortunately, these language-specific editor settings overriden by the
extension is not easily visible from the settings UI, and confuses users new to Go.
In the following issues, we are discussing and collecting ideas to improve
the situation without interrupting existing users.

  * [`editor.formatOnSave` and `editor.codeActionsOnSave`](https://github.com/golang/vscode-go/issues/1815)
  * [`editor.suggest.snippetsPreventQuickSuggestions`](https://github.com/golang/vscode-go/issues/1805)

## 2. Official Technical Reference & Guides (golang/website)

# Go website

[](https://pkg.go.dev/golang.org/x/website)

This repo holds content and serving programs for the go.dev and golang.org web sites.

Content is in \_content/ (go.dev) and tour/ (go.dev/tour).
Server code is in cmd/ and internal/.

To run the combined go.dev+golang.org server to preview local content changes, use:

    go run ./cmd/golangorg

The supporting programs cmd/admingolangorg and cmd/googlegolangorg
are the servers for admin.golang.org and google.golang.org.
(They do not use the \_content/ directories.)

Each command directory has its own README.md explaining deployment.

## JS/TS/CSS Formatting

This repository uses [eslint](https://eslint.org/) to format JS and TS files,
and [stylelint](https://stylelint.io/) to format CSS files.

See also:

- [CSS](https://go.dev/wiki/CSSStyleGuide)
- [JavaScript](https://google.github.io/styleguide/jsguide.html)
- [TypeScript](https://google.github.io/styleguide/tsguide.html)

It is encouraged that all JS, TS, and CSS code be run through formatters before
submitting a change. However, it is not a strict requirement enforced by CI.

### Installing npm Dependencies:

1. Install [docker](https://docs.docker.com/get-docker/)
2. Create a .gitignore file at repo root
3. Add .gitignore and node_modules to .gitignore
4. Run `./npm install`

### Run ESlint

    ./npx eslint [options] [file] [dir]

### Run Stylelint

    ./npx stylelint [input] [options]

## TypeScript Support

TypeScript files served from _content are transformed into JavaScript.
Reference .ts files in html templates as module code.

  `<script type="module" src="/ts/filename.ts">`

Write unit tests for TypeScript code using the [jest](https://jestjs.io/)
testing framework.

### Run Jest

    ./npx jest [TestPathPattern]

## Deploying

Each time a CL is reviewed and submitted, the code is deployed to App Engine.
See [cmd/golangorg/README.md](cmd/golangorg/README.md#deploying-to-go_dev-and-golang_org) for details.

## Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to
this repository, see https://go.dev/doc/contribute.

The git repository is https://go.googlesource.com/website.

The main issue tracker for the website repository is located at
https://go.dev/issues. Prefix your issue with "x/website:" in the
subject line, so it is easy to find.