git svn dcommit error ?

[Geert Janssens]

I recently switched to using a git repo as described in the wiki. This has 
worked fine until yesterday.

I'm currently trying to run a git svn dcommit to push some of my local commits 
to svn. This results in an error however:

$ git svn dcommit                                                                                                                                           
Committing to svn+ssh://gjanssens@svn.gnucash.org/repo/gnucash/trunk ...                                                                                                                  
        M       src/gnome-utils/assistant-utils.c                                                                                                                                         
Transaction is out of date: File '/gnucash/trunk/src/gnome-utils/assistant-
utils.c' is out of date at /usr/libexec/git-core/git-svn line 576


My tree is as follows:

... - A' - A - T - B

A: revision just before trunk
A': the revision even just before that
T: current trunk revision, both local and remote trunks
B: branch I'm trying to push to svn

I did run a git-update on trunk before trying to push. Trunk is up to date and 
branch B is properly rebased on trunk, at least as far as I can see in gitk.

What confuses me is this: the error is about src/gnome-utils/assistant-utils.c
This file is last changed in revision A, and already pushed to svn. There are 
no further changes to this file in either trunk or branch B. For some reason 
git doesn't seem to agree on and tries to push the change anyway.

I suspect this is due to how revision A got committed:
A' and A were two revisions I created on two separate branches. When they were 
ready, I first switched to the branch with A' and ran git svn dcommit. Next I 
switched to trunk and ran git-update. This didn't change the remotes, because 
the master repo at github hadn't synched yet. So at this point, local trunk 
and the remote trunks were not pointing at the same commit. From there I 
immediatly switched to the branch with A, rebased it to trunk and dcommitted 
it as well. This worked fine on the svn side, but I wonder if this confused 
things on the git side.

Basically, that leaves me with two questions:
1. how to recover from this situation ?
2. how can I/we prevent this from happening is the future ?

Geert