Fetching from remote with explicit refspec raises error incorrectly

[rrei]

GitPython version: 1.0.2
File: git/remote.py
Line: 646
OS: Ubuntu 14.04LTS

Passing a refspec to git fetch through a remote, as in
repo.remotes.origin.fetch("+refs/heads/*:refs/remotes/origin/*")
will raise an error if the remote has no fetch refspec defined in the config:

AssertionError: Remote '%s' has no refspec set.
You can set it as follows: 'git config --add "remote.origin.fetch +refs/heads/*:refs/heads/*"'.

Also, note that the error message is incorrectly formatted because the remote's name is replaced only in the second line of the message (a %s appears in the first line of the final message).

The _assert_refspec() method should not be called if one or more refspecs were given as arguments to fetch().

[Byron]

Thanks for letting me know - the incorrectly formatted message should now be fixed.

However, I am not quite sure why there is no 'fetch' configuration provided here. In a previous commit it is stated that gitpython needs this to work.

Just not making the assertion should therefore result in a more difficult to debug error. Maybe you can try removing the assertion in question to see if GitPython will work anyway ?

[rrei]

I was testing this briefly and found out that the repo has no fetch refspec because I cloned it as a bare repo. Also, I commented the _assert_refspec() call, tried a fetch, and it worked like a charm.

IPython 4.0.0 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: import git

In [2]: r = git.Repo.clone_from('git://example.com/repos/aletheia.git', 'aletheia.git', branch='develop', bare=True)

In [3]: r.refs
Out[3]: 
[<git.Head "refs/heads/develop">,
 <git.Head "refs/heads/master">,
 <git.TagReference "refs/tags/0.1.0">]

In [4]: r.remotes.origin.fetch('+refs/heads/*:refs/remotes/origin/*')
Out[4]: 
[<git.remote.FetchInfo at 0x7feb9e88a940>,
 <git.remote.FetchInfo at 0x7feb9e88a998>]

In [5]: r.refs
Out[5]: 
[<git.Head "refs/heads/develop">,
 <git.Head "refs/heads/master">,
 <git.RemoteReference "refs/remotes/origin/develop">,
 <git.RemoteReference "refs/remotes/origin/master">,
 <git.TagReference "refs/tags/0.1.0">]

So, I would be inclined to conclude that the assertion should only be made if no refspec argument is given:

if refspec is None:
    self._assert_refspec()

Are there any impediments to this change?

[Byron]

If there are any impediments, then I don't see them.
Would you be fine committing these changes and submit a PR ?

[rrei]

Sure, which branch would you like to fork from? (I'll be assuming it is "master" until I hear back from you)