Rebasing local git branches on the new repo

Jason Merrill
Tue Jan 14 06:17:00 GMT 2020

On 1/13/20 6:00 AM, Jonathan Wakely wrote:
> On Sun, 12 Jan 2020 at 18:08, Jonathan Wakely <> wrote:
>> Now that I've switched my local git tree to the new repo (by changing
>> the URL for the 'origin' remote, and adding the old one as a 'gcc-old'
>> remote) I've been experimenting with these commands to switch some of
>> the ~400 local branches to be based on the new repo instead of the
>> git-svn mirror.
>>        # The local branch to update
>>        branch=foo
>>        # The previous upstream for the branch
>>        upstream=$(git rev-parse --symbolic-full-name $branch@{u} | sed
>> -n s,^refs/heads,gcc-old,p)
>>        # find the last upstream commit in the branch
>>        base=$(git merge-base $branch $upstream)
>>        # extract its SVN revision
>>        svnrev=$(git log -1 $base | sed -n
>> '/git-svn-id:/s/.*@\([[:digit:]]\+\) .*/\1/p')
>>        # find equivalent commit in master
>>        onto=$(git log --pretty=format:%H --grep="From-SVN: r$svnrev" $branch@{u})
>>        git rebase --onto $onto $upstream $branch
>> Use at your own risk!
> The attached script is a slightly more robust version of those commands.

Nice.  I adjusted your script for my situation where I have a separate 
local repository for the new git (my old one is corrupt from unwise use 
of alternates), using format-patch/am for moving commits between them:

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