git-drover(1)

# git-drover(1) Manual Page

## NAME

git-drover - Apply a commit from the trunk to a release branch, or from one release branch to another.

## SYNOPSIS

    git drover --branch <branch>
               (--cherry-pick <change> | --continue [path_to_workdir] |
                --abort [path_to_workdir])
               [--parent_checkout <path-to-existing-checkout>]
               [--verbose] [--dry-run]

## DESCRIPTION

`git drover` applies a commit to a release branch. It creates a new workdir from an existing checkout to avoid downloading a new checkout without affecting the existing checkout.

`git drover` does not support reverts. See the EXAMPLE section for the equivalent sequence of commands to run.

## OPTIONS

--branch <branch>

  The branch to cherry-pick the commit to.

--cherry-pick <commit>

  The commit to cherry-pick.

--continue [path_to_workdir]

  Continue a cherry-pick that required manual resolution. The path to the drover workdir is optional. If unspecified, the current directory is used.

--abort [path_to_workdir]

  Abort a cherry-pick that required manual resolution and clean up its workdir. The path to the drover workdir is optional. If unspecified, the current directory is used.

--parent_checkout

  The path to the chromium checkout to use as the source for a creating git-new-workdir workdir to use for cherry-picking. If unspecified, the current directory is used.

-v
--verbose

  Enable verbose logging.

--dry-run

  Skip landing the cherry-pick. Just ensure that the commit can be cherry-picked into the branch.

## EXAMPLE

### PREREQUISITES

Before working with branches, you must `gclient sync --with_branch_heads` at least once to fetch the branches.

#### Merge Example

    # Here's a commit (from some.committer) that we want to 'drover'.
    $ git log -n 1 --pretty=fuller
    commit c980d966aab8516cc651409da4bf21ca8a4a3613
    Author:     some.committer <some.committer@chromium.org>
    AuthorDate: Thu Apr 10 08:54:46 2014 +0000
    Commit:     some.committer <some.committer@chromium.org>
    CommitDate: Thu Apr 10 08:54:46 2014 +0000

        This change needs to go to branch 9999

    # Now do the 'drover'.
    $ git drover --branch 9999 --cherry-pick c980d966aab8516cc651409da4bf21ca8a4a3613
    Going to cherry-pick
    """
    commit c980d966aab8516cc651409da4bf21ca8a4a3613
    Author: some.committer <some.committer@chromium.org>
    Date:   Thu Apr 10 08:54:46 2014 +0000

        This change needs to go to branch 9999
    """
    to 9999. Continue (y/n)? y

    # A cl is uploaded to rietveld, where it can be reviewed before landing.

    About to land on 9999. Continue (y/n)? y
    # The cherry-pick cl is landed on the branch 9999.

#### Merge with Conflicts Example

    # Here's a commit (from some.committer) that we want to 'drover'.
    $ git log -n 1 --pretty=fuller
    commit 2d78cf765179c7be5e7e6d1e4565a0d3769e9174
    Author:     some.committer <some.committer@chromium.org>
    AuthorDate: Thu Apr 10 08:54:46 2014 +0000
    Commit:     some.committer <some.committer@chromium.org>
    CommitDate: Thu Apr 10 08:54:46 2014 +0000

        This change needs to go to branch 9999

    # Now do the 'drover'.
    $ git drover --branch 9999 --cherry-pick 2d78cf765179c7be5e7e6d1e4565a0d3769e9174
    Going to cherry-pick
    """
    commit 2d78cf765179c7be5e7e6d1e4565a0d3769e9174
    Author: some.committer <some.committer@chromium.org>
    Date:   Thu Apr 10 08:54:46 2014 +0000

        This change needs to go to branch 9999
    """
    to 9999. Continue (y/n)? y

    Error: Patch failed to apply.

    A workdir for this cherry-pick has been created in
      /tmp/drover_9999

    To continue, resolve the conflicts there and run
      git drover --continue /tmp/drover_9999

    To abort this cherry-pick run
      git drover --abort /tmp/drover_9999

    $ pushd /tmp/drover_9999
    # Manually resolve conflicts.
    $ git add path/to/file_with_conflicts
    $ popd
    $ git drover --continue /tmp/drover_9999

    # A cl is uploaded to rietveld, where it can be reviewed before landing.

    About to land on 9999. Continue (y/n)? y
    # The cherry-pick cl is landed on the branch 9999.

#### Revert Example

    # Make sure we have the most up-to-date branch sources.
    $ git fetch

    # Checkout the branch with the change we want to revert.
    $ git checkout -b drover_9999 branch-heads/9999
    Branch 'drover_9999' set up to track remote ref 'refs/branch-heads/9999'.

    # Here's the commit we want to revert.
    $ git log -n 1
    commit 54f88a53372983c7aecacfb9a4d2fa63501fda58
    Author: some.committer <some.committer@chromium.org>
    Date:   Thu Apr 10 08:54:46 2014 +0000

        This change is horribly broken.

    # Now do the revert.
    $ git revert 54f88a53372983c7aecacfb9a4d2fa63501fda58

    # That reverted the change and committed the revert.
    $ git log -n 1
    commit 4d932bdd1071e318e6a4d3d6fd6034f9105cad5a
    Author: you <you@chromium.org>
    Date:   Thu Apr 10 09:11:36 2014 +0000

        Revert "This change is horribly broken."

        This reverts commit 54f88a53372983c7aecacfb9a4d2fa63501fda58.

    # As with old drover, reverts are generally OK to commit without LGTM.
    $ git cl upload -r some.committer@chromium.org --send-mail
    $ git cl land --bypass-hooks

If your cherrypick onto a release branch gets reverted, do not create a new cherrypick from master onto that release branch. Instead, use the "Reland" button on the original cherrypick CL.

#### Manual Merge Example

    # Make sure we have the most up-to-date branch sources.
    $ git fetch

    # Here's a commit (from some.committer) that we want to 'drover'.
    $ git log -n 1 --pretty=fuller
    commit 8ed5a6585548f2092890b404f6ff49bd5ce6ab9a
    Author:     some.committer <some.committer@chromium.org>
    AuthorDate: Thu Apr 10 08:54:46 2014 +0000
    Commit:     some.committer <some.committer@chromium.org>
    CommitDate: Thu Apr 10 08:54:46 2014 +0000

        This change needs to go to branch 9999

    # Checkout the branch we want to 'drover' to.
    $ git checkout -b drover_9999 branch-heads/9999
    Branch 'drover_9999' set up to track remote ref 'refs/branch-heads/9999'.

    # Now do the 'drover'.
    # IMPORTANT!!! Do Not leave off the '-x' flag
    $ git cherry-pick -x 8ed5a6585548f2092890b404f6ff49bd5ce6ab9a
    [drover_9999 77a956b] This change needs to go to branch 9999
     Author: some.committer <some.committer@chromium.org>
     Date: Thu Apr 10 08:54:46 2014 +0000
     1 file changed, 1 insertion(+)
     create mode 100644 modified_file

    # That took the code authored by some.committer and committed it to
    # the branch by the person who drovered it (i.e. you).
    $ git log -n 1 --pretty=fuller
    commit 77a956ba0f28eb29ed009f58a5d71b6a10283358
    Author:     some.committer <some.committer@chromium.org>
    AuthorDate: Thu Apr 10 08:54:46 2014 +0000
    Commit:     you <you@chromium.org>
    CommitDate: Thu Apr 10 09:11:36 2014 +0000

        This change needs to go to branch 9999

        (cherry picked from commit 8ed5a6585548f2092890b404f6ff49bd5ce6ab9a)

    # Looks good. Ship it!
    $ git cl upload
    # Wait for LGTM or TBR it.
    $ git cl land
    # Or skip the LGTM/TBR and just 'git cl land --bypass-hooks'

If `git cl upload` errors out, the branch you’re uploading to probably has a CL with the same Change-Id. Instead of cherry-picking manually, use the Reland button in the Gerrit UI to create a new CL, and patch that CL into your client.

## SEE ALSO

git-cherry-pick(1), git-revert(1)

## CHROMIUM DEPOT_TOOLS

Part of the chromium depot_tools(7) suite. These tools are meant to assist with the development of chromium and related projects. Download the tools by checking out the git repository.