git-merge rich history recovery

[Athos Ribeiro]

On Wed, Aug 14, 2024 at 04:57:13PM -0700, Bryce Harrington wrote:
>Athos raised an issue last week about how when annotating delta about
>upstream status while doing git-ubuntu merges, if another package later
>does a merge of the package and does not use git-ubuntu style, you can
>lose the rich history (and thus also the annotation).
>
>I mentioned this also happens frequently with packages suffering
>git-ubuntu's "empty dir" bug (LP: #1917877).  Several of the packages I
>merge have this problem, so I've gotten accustomed to recovering the
>rich history from my previous work.  This is what I'm currently using:
>
>##############
>local last_remote
>last_remote=$(git branch -a | grep -E "remotes/.*/merge-" | sort -V | tail -1 | xargs) || {
>    error "Could not determine last merge remote to base off of"
>    return 1
>}
>branch_name="${last_remote##*/}"
>
>git checkout "${last_remote}" -b "${branch_name}" || {
>    error "Could not checkout '${branch_name}'"
>    return 1
>}
>git tag -f base || {
>    error "Failed to tag base"
>    return 1
>}
>
>git checkout ubuntu/devel || {
>    error "Could not checkout ubuntu/devel"
>    return 1
>}
>
>git rebase base || {
>    # TODO: If the conflict is with debian/patch/series,
>    #       then likely we can just take the debian version and
>    #       then append all the additional ubuntu patches to the end.
>    # TODO: If the conflict is with changelog, then take the ubuntu
>    #       version of the file, and then prepend all Debian's
>    #       new changelog entries on top.
>    # TODO: Then git add, and git rebase --continue
>    error "Could not rebase to base"
>    return 1
>}
>info "Successfully imported past merge work"
>#############
>
>
>That first step is going to need some adjustment, because it assumes YOU
>were the last merger, and assumes my style of branch naming for merges
>(i.e. "merge-" and alphanumerically sortable).  So YMMV on that and TBD
>to handle someone else as the last merger, but hopefully the above gives
>some inspiration.
>
>Bryce

Thanks, Bryce!

I will try it next time I face the issue.

I suppose this can eventually land under ubuntu-helpers :)

-- 
Athos Ribeiro