warning: refname 'xxx' is ambiguous when using git-svn

To avoid the conflict messages, when referring to local branches, prefix them with heads/

for example, the conflicting branch topic

$ git diff topic remotes/topic
warning: reframe 'topic' is ambiguous.
...

becomes

$ git diff heads/topic remotes/topic
...

If you pass the --prefix=svn/ flag to the git svn clone command, then all of the Subversion branches would be named like remotes/svn/branchname. If this is acceptable to you, it fixes the "refname is ambiguous" warning. It also gives you a nice way of referring to the remote svn branches, as in for instance if you want to create a local tracking branch it would be something like:

$ git checkout -b branchname svn/branchname

The local branch then has the same name as the remote svn branch, and no ambiguous refname problem.

If you just want to get rid of warning, set core.warnAmbiguousRefs to false:

git config --global core.warnambiguousrefs false

If you want this behavior only for single repository, omit --global flag.

It can be possible that you have another 'trunk' and 'coolfeature' as a tag. In this case, git doesn't know if you refer to branch or tag. Rename the tags and check if git doesn't report "ambiguous" name