# Ignoring Files from Format and Presubmit Checks

This document describes all the ways to ignore files from format and presubmit
checks in the Brave codebase. The main use cases are ignoring files that are
vendored from external sources or generated by tools.

## Quick Reference Table

| File Type / Check    | Configuration File                        |
| -------------------- | ----------------------------------------- |
| **C/C++**            | add `.clang-format` in target directory   |
| **Java**             | does not support configuration            |
| **JS/TS/CSS/etc.**   | `//brave/.prettierignore`                 |
| **Python**           | `//brave/.yapfignore`                     |
| **Rust**             | `//.rustfmt.toml` (via patching)          |
| **Swift**            | add `// swift-format-ignore-file` comment |
| **Presubmit Checks** | `//brave/chromium_presubmit_config.json5` |

## Detailed Instructions

### C/C++ Files (clang-format)

To ignore C/C++ files from clang-format checks, you need to add a
`.clang-format` file in the target directory with the following configuration:

```
DisableFormat: true
SortIncludes: false
```

This will disable both formatting and include sorting for files in that
directory and its subdirectories.

### Java Files

Chromium uses `google-java-format` for Java code formatting. Unlike other
formatters, `google-java-format` does not support ignore files or
directory-level configuration.

### JavaScript/TypeScript/CSS/HTML Files

To ignore JavaScript, TypeScript, CSS, HTML, and other files handled by
Prettier, add them to `//brave/.prettierignore`.

The `.prettierignore` file uses gitignore-style patterns to exclude files from
Prettier formatting.

### Python Files

To ignore Python files from formatting checks, add them to
`//brave/.yapfignore`.

The `.yapfignore` file uses pattern matching (fnmatch) to exclude files from
yapf formatting. Add one pattern per line.

### Rust Files

To ignore directories from rustfmt formatting checks, you need to modify
`//.rustfmt.toml` via patching.

The `.rustfmt.toml` file contains an `ignore` array that lists directories to
exclude from rustfmt formatting. Add directory patterns to this array to ignore
them.

### Swift Files

To ignore Swift files from swift-format checks, add a comment at the top of the
file:

```swift
// swift-format-ignore-file
```

To ignore specific lines within a Swift file, add a comment before the line:

```swift
// swift-format-ignore
let example = ...
```

The swift-format configuration is located at `//brave/ios/.swift-format` and
controls formatting rules, but file-level ignores must be done using inline
comments.

See for more details:
https://github.com/swiftlang/swift-format/blob/main/Documentation/IgnoringSource.md

### Presubmit Checks

To ignore files from presubmit checks, you need to adjust the
`default_files_to_skip` configuration in
`//brave/chromium_presubmit_config.json5`.

This configuration controls which files are skipped during presubmit checks.
**This does not affect the formatting checks.**