DevTools Version Control

Overview

Chrome DevTools uses Gerrit for code review. The standard workflow is one branch per Change List (CL) and one commit per branch. Instead of multiple commits, you amend your single commit locally.

Core Workflow

Creating a New CL

To start a new task, create a new branch from main:

git new-branch <branch-name>

Note: This automatically sets the upstream to origin/main.

Making Changes

1. Make your changes.
2. Stage them: git add <files>.
3. Create the commit: git commit -m "Your message".

Updating a CL (Amending)

To update your CL after feedback or more work:

1. Make more changes.
2. Stage them: git add <files>.
3. Amend the commit: git commit --amend.

Stacked CLs

If CL B depends on CL A:

1. While on branch A, create branch B:
   bashCopy

   git new-branch --upstream_current <branch-B>
   

2. Develop on branch B.
3. When uploading B, Gerrit will show the dependency on A.

Reparenting

If you need to change the base of a branch (e.g., move CL B to be based on main instead of CL A):

git reparent-branch main

Or to make it depend on another branch C:

git reparent-branch <branch-C>

Syncing with Upstream

To update all your branches with the latest changes from main and their respective upstreams:

git rebase-update

Initial upload

When a CL is ready, upload it with:

git cl upload -d --commit-description="<description>"

• Use the same writing style as the current committer
• Keep line length below 72
• Add a "Bug: " or "Bug: None" trailer on a separate line.
• Amend formatter/linter changes and fix linter issues.

Subsequent upload

To upload an updated CL:

git cl upload -d -t "<one sentence patch set description>"

Quick Reference

Common Mistakes

• Multiple commits on one branch: Gerrit expects one commit per CL. Always commit --amend.
• Using git checkout -b: Does not set up tracking information correctly for depot_tools. Use git new-branch.
• Manual rebasing of stacked branches: Can be complex. Use git rebase-update or git reparent-branch to let depot_tools handle the tracking updates.