Drover is a tool, included with depot tools, that allows developers (should be a committer) to rapidly merge and revert changes on our trunk/branches without any previously checked out working copy. A typical drover command merge/revert with no conflicts, takes about 1 minute to run from start to finish.
Merging to a branch and don't know the branch number? The TPM (release manager) approving the merge will have it.
After merging to a release branch, try to watch http://go/stablebuilders (for stable branches) and http://go/branchbuilders (for dev/beta branches) to make sure everything's all right.
For merges on Windows and reverts, please see
Follow steps for checking out a release branch at http://www.chromium.org/developers/how-tos/get-the-code/working-with-release-branches to sync the branch heads.
If this is the first time you've tried to merge into a branch, you may run into the following error when trying to git cl land the change:
error: failed to push some refs to 'https://chromium.googlesource.com/a/chromium/src.git'
ERROR:git-retry:Process failure was not known to be transient; terminating with return code 1
Push failed with exit code 1.
! HEAD:refs/pending/branch-heads/2311 [remote rejected] (prohibited by Gerrit)
If you see this error, and you are a committer (went through the process described here) you may not have been added to the chromium-committers gerrit group yet (the group update process lags behind a bit). File a bug with the Infra-Git label, so you can be added to the group manually.
If you've started merge with "git drover" and made any manual edit, "git cl upload" doesn't work to upload the new snapshot. Use "git drover --continue".
If the merged branch doesn't build locally, you may need to port DEPS change from the version-number named branch (e.g. https://chromium.googlesource.com/chromium/src.git/+/53.0.2785.24). DEPS changes after branch cut are not made on the release branch but in the version-number named branches.
NOTE: this is only needed for branches older than M46. As of M46, Blink is merged into Chromium.