[git-buildpackage] Is there a way to manually reconstruct the upstream branch if it diverged?

[Guido Günther]

Hi,
On Sat, Oct 25, 2025 at 05:33:07PM +0200, Markus Blatt wrote:
> Hi,
> 
> Am Fri, Oct 24, 2025 at 10:39:03PM +0200 schrieb Guido Günther:
> > 
> > On Fri, Oct 24, 2025 at 09:13:57PM +0200, Markus Blatt wrote:
> > > Hi,
> > > 
> > > I must have somehow messed up my local upstream branch before running "gbp import --uscan".
> > > I think I did a "git reset --hard" with a wrong earlier commit and lost at least one tag on the upstream
> > > branch
> > 
> > "git reflog"
> 
> Thanks, I will also look into that.
> 
> > 
> > apart from that if you have the "lost" commits on the remote you can
> > just fetch that and rebase (after all it's a git branch like any other)
> > 
> 
> my problem with that is that tags won't match and I get a lot of ugly merge conficts, that I have to resolve.
> 
> What I did now was just to merge in the the tag used for a Debian release. Now I have a merge conflict and gbp
> push complains that

As I've not seen the trees I can only give very generic advice:

You can always create a fake merge similar to what `gbp import-orig`
does in order to not having to resolve conflicts manually. `--ours`
might also do the trick (depending on the trees). 

> 
> gbp:info: Pushing 17b5bd5a99388d23b9085c58f30f8b572326306e to origin:refs/heads/upstream
> gbp:error: Error running git push: X11 forwarding request failed on channel 0
> To salsa.debian.org:science-team/opm-common.git
>  ! [rejected]            17b5bd5a99388d23b9085c58f30f8b572326306e -> upstream (non-fast-forward)
> Fehler: Fehler beim Versenden einiger Referenzen nach 'salsa.debian.org:science-team/opm-common.git'
> Hinweis: Aktualisierungen wurden zurückgewiesen, weil die Spitze eines versendeten
> Hinweis: Branches hinter seinem externen Gegenstück zurückgefallen ist. Checken Sie
> Hinweis: diesen Branch aus und führen Sie die externen Änderungen zusammen
> Hinweis: (z. B. 'git pull ...') bevor Sie erneut "push" ausführen.
> Hinweis: Siehe auch die Sektion 'Note about fast-forwards' in 'git push --help'
> Hinweis: für weitere Details.
> gbp:error: Failed to push some refs.
> 
> It is not pushing HEAD but the commit the  release is based on. That can't work.
> 
> $ git log -2 --oneline upstream
> 5a5db414c (HEAD -> upstream) Merge branch 'upstream-backup' into upstream
> 17b5bd5a9 (tag: upstream/2025.10+ds, upstream-backup) New upstream version 2025.10+ds
> 
> But pushing HEAD manually might/should work. Hence my question is:
> 
> If I push the HEAD, will that cretae problems for the next gbp import
> --uscan command?

As above: without the trees I can only assume that no. As noted
initially it is just a git branch as any other which can be rebased,
merged, etc.

Cheers,
 -- Guido

> 
> Cheers,
> 
> Markus
> 
> > 
> > > 
> > > Unfortunately, I only noticed this after uploading the new version to unstable when I ran gbp push.
> > > It failed because the remote and local upstream branches aree diverged.
> > > 
> > > The current status is
> > > - pristine-tar branch has the last tarball and is pushed
> > > - master branch (which holds the status for Debian unstable), has the tag for the last uploaded Debian release.
> > > - local upstream branch has diverged from origin/upstream.
> > > 
> > > Is there a good way to manually fix my local upstream branch and push?
> > > 
> > > Thanks a lot for your help.
> > > 
> > > Best,
> > > 
> > > Markus
> > > 
> > > 
> > > 
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> > > 
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> 
> -- 
> 
> Dr. Markus Blatt - HPC-Simulation-Software & Services http://www.dr-blatt.de
> Pedettistr. 38, 85072 Eichstätt, Germany,  USt-Id: DE279960836
> Tel.: +49 (0) 160 97590858
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