Revision control
Copy as Markdown
Other Tools
---
name: gn-check-autofix
description: Automatically fix GN check errors in WebRTC BUILD.gn files. Use when encountering "Include not allowed", "rtc_source_set shall not contain cc files", or when needing to clean up non-absolute dependencies.
---
# GN Check Autofix
This skill provides instructions for using `tools_webrtc/gn_check_autofix.py` to
automatically resolve common GN build configuration errors in WebRTC.
## Core Workflows
### Fix Missing Dependencies
When you see "Include not allowed" errors from `gn gen --check`, use this
workflow:
1. Run the autofix tool on your output directory:
```bash
tools_webrtc/gn_check_autofix.py -C <dir>
```
2. The tool will:
- Identify targets missing dependencies.
- Add the missing `deps` to the appropriate `BUILD.gn` files.
- Automatically run `gn format` on modified files.
### Fix rtc_source_set Violations
If you see "rtc_source_set shall not contain cc files", the tool will
automatically convert them to `rtc_library`:
1. Run the tool:
```bash
tools_webrtc/gn_check_autofix.py -C <dir>
```
### Clean Up Dependencies
To remove all non-absolute dependencies (those not starting with `//`) from
specific `BUILD.gn` files:
```bash
tools_webrtc/gn_check_autofix.py -r path/to/BUILD.gn
```
*Note: This preserves absolute dependencies (starting with `//`) and targets
ending in `_test`, `_tests`, `_unittest`, or `_unittests`.*
## Integration with Include Cleaner
This tool is the recommended second step after running `webrtc-include-cleaner`.
While the include cleaner updates your C++ source files, `gn-check-autofix`
synchronizes your `BUILD.gn` files to match.
## Parameters
- `-C <dir>`: Path to a local build directory (e.g., `out/Default`). The tool
internally runs `gn gen --check --error-limit=20000`.
- `-r <files>`: Remove all non-absolute dependencies from the specified files.
- `--error-limit`: Can be used to override the default error cap.
## Post-Fix Steps
After the tool runs, always verify the changes:
1. **Deduplicate**: The tool may occasionally add a dependency that is already
present. Check the `deps` list for duplicates.
2. **Regenerate GN**: Run `gn gen <dir>` to confirm errors are resolved.
3. **Format**: The tool runs `gn format`, but a final `git cl format` is
recommended for consistency.
4. **Review**: Check the diff to ensure dependencies were added to the correct
targets.