trino

# Trino — Claude guidance

**Before writing Java code, you must first read [`.github/DEVELOPMENT.md`](.github/DEVELOPMENT.md)
in full** — it's the authoritative source for code-style rules (mocks, `var`, switch statements,
method naming, `format()`, `TrinoException` error codes, AssertJ, Guava immutables, and more).
This file intentionally does not duplicate those rules; skipping the read means missing them.
Violations are also caught mechanically by modernizer
([`.mvn/modernizer/violations.xml`](.mvn/modernizer/violations.xml)), checkstyle (from Airbase),
and IntelliJ inspections via `mcp__idea__get_file_problems`.

For other topics not covered here (Web UI build, release process, Vector API, IDE setup rationale),
see the same `DEVELOPMENT.md`.

## JetBrains MCP server

Trino is developed in IntelliJ. If you run Claude Code with the JetBrains MCP server enabled,
the assistant can drive the IDE directly. Install: https://github.com/JetBrains/mcp-jetbrains.

When available, Claude should prefer these over shell equivalents:
- `mcp__idea__get_file_problems` before committing — surfaces IntelliJ inspection results
  (error-prone, unused imports, nullability) without a full Maven build.
- `mcp__idea__search_symbol` / `mcp__idea__get_symbol_info` for symbol navigation in a codebase
  with many overloaded names like `Metadata`, `Session`, `Block`.
- `mcp__idea__rename_refactoring` for API renames — safer than text substitution.

## Building

Fastest full build and install:

```bash
./mvnw clean install -T 2C -nsu -DskipTests -Dmaven.javadoc.skip=true -Dair.check.skip-all=true
```

It skips tests, Javadoc, and the airbase checks — run `./mvnw validate` before opening a PR.

## Java formatting

Run `mvnd airstyle:format` after Java edits — the `airstyle-maven-plugin` (`io.airlift:airstyle-maven-plugin`)
applies the canonical Airstyle scheme, which is what CI checks. Scope a single file with
`mvnd -pl <module> airstyle:format -Dincludes=**/FileName.java`, and use `airstyle:check` to verify
without rewriting. Rules not covered by the formatter:

- No wildcard imports (e.g. `import io.trino.spi.*`) — checkstyle catches these on build; easier
  to avoid writing them.
- Braces required around single-statement `if` / `for` / `while` bodies — the formatter does not
  add missing braces.
- No `@author` in JavaDoc — commit history is the record.

Topic-specific conventions live under [`.claude/rules/`](.claude/rules/) and auto-load when Claude
reads matching files (e.g. `*Config.java` triggers the config-properties rule).