How to set upstream branch in git-svn?

问题:

While working on a usual git repository a local branch usually tracks a corresponding remote upstream branch. This way I can easily see, whether I am ahead or behind of my upstream branch and therefore if I need to push or pull to bring them in sync. Also my prompt immediately shows this state, which is very convenient.

Now I am working on a SVN repository using git-svn. I used --prefix=svn for the clone, therefore git branch -r lists svn/trunk as a remote branch, but (although git svn rebase works without problems) it is not configured as an upstream branch for my master branch.

I tried to set the tracking information manually but it failed:

$ git branch -r
  svn/trunk
$ git branch --set-upstream-to=svn/trunk
fatal: Cannot setup tracking information; starting point 'svn/trunk' is not a branch.

Is there some way to track an svn upstream branch?

Is there some other easy way to know whether I am ahead or behind to that branch? (Looking at gitk --all is currently the only way I am aware of.)

Is there even some way to make my (bash __git_ps1) prompt show that information?

---

$ git --version
git version 1.9.0.msysgit.0

回答1:

This seems to be a bug introduced in git 1.9, since --set-upstream-to worked before exactly as you mention.
_{And strace displays correct locating and reading of the upstream branch ref, then however it's ignored for some reason.}

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My workaround for this issue is manual editing of .git/config:

$ cat >> .git/config << EOF

[branch "master"]
        remote = .
        merge = refs/svn/trunk
        rebase = true
EOF

— which should be equivalent to:

git branch --set-upstream-to=svn/trunk master

&& git config branch.master.rebase true (which you'll want with svn anyway)

— but is not, because of a bug! "Of course my refs/svn/trunk is a branch!" you say, and edit the config directly (with just a little bit of gentle force).

Your svn trunk could be named differently in git depending on how you cloned the repo (-s, -T, --prefix options to git svn clone). Just do a git branch -avv and find the correct one. For example, one possible name is refs/remotes/git-svn; or refs/svn/trunk as above; or even something else.

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Update Nov 2015

I still reproduce this on git version 2.1.4. Anyone to bother file a bug report?

回答2:

git-svn will store the configuration data in .git/config, for example in one of my repo the config is like:

[core]
    repositoryformatversion = 0
    filemode = true
    bare = false
    logallrefupdates = true
[svn-remote "svn"]
    url = http://svn.repo.com/repos/myrepo
    fetch = trunk:refs/remotes/trunk
    branches = branches/*:refs/remotes/*
    tags = tags/*:refs/remotes/tags/*

In the [svn-remote "svn"] section you can see all the git-svn configurations. In the branches section you see all the branches on the remote svn repo.

When I need to follow a svn branch in my local git repo I usually do these steps:

1. I check that the config is correctly configured with all the branches and the tags.
2. I do a git svn fetch, in that way git will fetch all the data in the repo for all the branches

3. I check that all the branches / tags are present as output of git branch -a, for example:

   master
   prod
   scenarioParametro
   remotes/tags/alpha-1
   remotes/trunk
   

4. I create a local git branch to track a remote one with:

   git branch alpha-1 remotes/tags/alpha-1 --track
   

In this way the newly created alpha-1 branch will follow the remotes/tags/alpha-1, and you can do the rebase and dcommit commands.

回答3:

This was still a problem for me using git 1.9.5.

And I did not get any of the solutions mentioned here to work, but this worked:

git rebase origin/remote-branch-name

After that git svn dcommit -n shows that it will indeed commit to that svn branch.

---

Update: I had the same problem again and this time the above didn't work. I just got the message: Current branch master is up to date. However using:

git rebase -i origin/remote-branch-name

forced the rebase anyway and after that the upstream was set correctly.

回答4:

Since nobody answered this:

Is there some other easy way to know whether I am ahead or behind to that branch?

Yes, it is. You can just use the general notion GIT uses for comparing refs also in this case. It’s ref_from..ref_to

E.g.:

git log master..svn/trunk – will give you all commits from svn/trunk that are missing in your master. I.e. incomming changes.

git log svn/trunk..master – will give you all commits from master that are missing in svn/trunk. I.e. outgoing changes.

Further explanation of the general syntax: here on SO and in the official GIT documentation