clang_tidy

A wrapper library and program that runs clang_tidy on the Flutter engine repo.

# Assuming you are in the `flutter` root of the engine repo.
dart ./tools/clang_tidy/bin/main.dart

By default, the linter runs over modified¹ files in the latest² build of the engine.

A subset of checks can also be fixed automatically by passing --fix:

dart ./tools/clang_tidy/bin/main.dart --fix

To configure what lints are enabled, see .clang-tidy.

💡 TIP: If you're looking for the git pre-commit hook configuration, see githooks.

Advanced Usage

Some common use cases are described below, or use --help to see all options.

Run with checks added or removed

To run adding a check not specified in .clang-tidy:

dart ./tools/clang_tidy/bin/main.dart --checks="<check-name-to-run>"

It's possible also to use wildcards to add multiple checks:

dart ./tools/clang_tidy/bin/main.dart --checks="readability-*"

To remove a specific check:

dart ./tools/clang_tidy/bin/main.dart --checks="-<check-name-to-remove>"

To remove multiple checks:

dart ./tools/clang_tidy/bin/main.dart --checks="-readability-*"

To remove all checks (usually to add a specific check):

dart ./tools/clang_tidy/bin/main.dart --checks="-*,<only-check-to-run>"

Specify a specific build

There are some rules that are only applicable to certain builds, or to check a difference in behavior between two builds.

Use --target-variant to specify a build:

dart ./tools/clang_tidy/bin/main.dart --target-variant <engine-variant>

For example, to check the android_debug_unopt build:

dart ./tools/clang_tidy/bin/main.dart --target-variant android_debug_unopt

In rarer cases, for example comparing two different checkouts of the engine, use --src-dir=<path/to/engine/src>.

Lint entire repository

When adding a new lint rule, or when checking lint rules that impact files that have not changed.

Use --lint-all to lint all files in the repo:

dart ./tools/clang_tidy/bin/main.dart --lint-all

Or, provide a regular expression to lint files that match:

dart ./tools/clang_tidy/bin/main.dart --lint-regex=".*test.*\.cc"

⚠️ WARNING: This may take a long time to run if a pattern is not provided or if the pattern matches a large number of files, i.e. on the order of thousands of files could take 30 minutes or more to run and lock your machine.