How do I fast-forward other tracking branches in git?

Question

We are working with the model of a single remote repository that all of us use. We branch for new features and reintegrate into a trunk branch. Our workflow is that we shoul

Answer 1

Try the following:

$ git pull trunk branch

Answer 2

Do you really need to update a local trunk branch?

Just fetch origin/trunk and merge it directly in the branch you are working on.
And that is Mark Longair's advice: git: fetch and merge, don’t pull.

---

Oliver mentions in his answer (upvoted):

git fetch upstream trunk:trunk

As he comments:

you can skip the merge and simply fast-forward, using a one-liner.

It does fast-forward the local branch trunk to the remote branch's HEAD.

See more at "git: update a local branch without checking it out?"

Answer 3

I think the easiest way to avoid the git checkout trunk, git pull, git checkout branch cycle is to use this answer:

git fetch upstream trunk:trunk

This does exactly what you want - fast-forward your local branch trunk to the remote branch's HEAD.

Answer 4

I agree with VonC's answer, but thought it might be fun to answer the question "How do you fast-forward master if you're on another branch?" anyway. I don't think there's a way to do this just using porcelain commands, but this script does the job (obviously you'd want to change master to trunk in your case):

#!/bin/sh

BRANCH=master
NEWER=origin/master

if [ x"$(git symbolic-ref HEAD)" = x"refs/heads/$BRANCH" ]
then
    echo "This doesn't make sense if you're already on the branch '$BRANCH'"
    echo "Just run: git merge $NEWER"
    exit 1
fi

BRANCH_HASH=$(git rev-parse $BRANCH)
NEWER_HASH=$(git rev-parse $NEWER)
MERGE_BASE=$(git merge-base $BRANCH_HASH $NEWER_HASH)

if [ "$MERGE_BASE" = "$BRANCH_HASH" ]
then
    git update-ref "refs/heads/$BRANCH" "$NEWER_HASH" "$BRANCH_HASH"
else
    echo "$BRANCH can't be fast-forwarded to $NEWER"
    exit 1
fi

Update 2012-10-20: this script was just a quick example; for a script that does the same but for merging any arbitrary commit-ish into a local branch (so long as the merge would be a fast-forward), see Jefromi's answer to a similar question.