A tool that automates rolling the browsers and JS engines pinned in DEPS, following go/dart-engprod/browsers.md.
The entry point is tools/roll_browsers.dart; this directory holds its implementation.
The tool relies on Google-internal infrastructure (LOAS credentials, the dart-eng tool proxy, MPA and Google Chat), so it can only be run by Googlers.
For each engine, the tool:
DEPS on origin/main with the latest upstream release and decides whether to roll, based on the engine's roll policy.DEPS with the relevant trybots, a CQ dry run and Auto-Submit, and waits for it to be approved and land. The MPA approvers are added as reviewers, and the CL is sent to the commit queue once it is approved if Auto-Submit hasn't already done so.Roll CLs are tagged with the browser-roll hashtag. If one is already open, the tool waits for it to land instead of uploading another.
The CL is committed in a temporary git worktree, so the working tree and current branch of the checkout running the tool are never touched.
| Engine | DEPS variable | Upstream source | Rolls when |
|---|---|---|---|
chrome | chrome_tag | Chrome for Testing beta | New major version, or pin is 14+ days old |
firefox | firefox_tag | Firefox stable | New major version, or pin is 14+ days old |
d8 | d8_tag | V8 canary (all platforms) | Pin is 30+ days old |
jsshell | jsshell_tag | Same version as Firefox | Firefox rolls, or it is behind Firefox |
jsc | jsc_tag | WebKitGTK JSC builds | Pin is 30+ days old |
The pin age is the time since the DEPS variable last changed on origin/main. Engines that share a version (Firefox and jsshell) always roll in the same CL.
Each run posts to a single thread in the Dart Web team Google Chat space (or the space given by --chat-space), sent as the user running the tool. The thread starts with the batched MPA approval links, or with the roll CL if no builds were needed. The roll CL, any failures (including CQ failures) and a final message when the CL lands are posted as replies.
gcert). If they expire during a run, the tool pauses until they are renewed.depot_tools on the PATH (for git cl) and the cipd client.tool-proxy-cli on the PATH, with access to the dart-eng tool proxy.From an SDK checkout, run:
dart tools/roll_browsers.dart
Use --dry-run first to see what would be rolled without requesting builds, uploading CLs or posting to chat:
dart tools/roll_browsers.dart --dry-run
A run can take a long time, since it waits for MPA approvals (up to 48 hours), packaging builds and the roll CL to land. It checks for progress every minute, backing off to every hour after three hours without progress, so it is best run somewhere it can be left alone, such as a tmux session.
The tool exits with a non-zero exit code if any step failed.
--only=<engine>: Only consider the given engines (chrome, firefox, d8, jsshell, jsc). Can be repeated.-n, --dry-run: Report what would happen without side effects.--ignore-cadence: Roll to any newer version, ignoring the roll policy.-r, --reviewer=<email>: Add a reviewer to the roll CL. Can be repeated.--chat-space=<id>: The Google Chat space to post the run's thread to.--reason=<text>: The justification for the tool proxy MPA requests.-h, --help: Show usage information.roller.dart: The overall roll flow (BrowserRoller).engines.dart: The engine definitions, roll policies, CIPD packages and trybots, and DEPS parsing.upstream.dart: Looks up the latest upstream releases.tool_proxy.dart: Requests CIPD packaging builds and looks up MPA approvers.gerrit.dart: Finds, uploads and tracks roll CLs.git.dart: Git operations on the SDK checkout.notifier.dart: Posts the run's Google Chat thread.process.dart: Subprocess and credential helpers.version.dart: Dotted version parsing and comparison.To add an engine, define it in engines.dart and add it to allEngines. Its name must match the tool proxy browser grant and the dart-internal/ci/<name> packaging builder.