gerrit broken / missing commit

Hi Lionel,

Apparently during the gerrit outage, something really bad happened, and
we lost a commit that is in the gerrit database, but not in gerrit's
git.

It's this commit:

https://github.com/LibreOffice/core/commit/a9da257bf9f57fdbfd0f400b30080abc4d582ec1

but there is no way to obtain it again - even though something like the
following should do it, it does not :-(

[with the github repo:]

git fetch origin a9da257bf9f57fdbfd0f400b30080abc4d582ec1:refs/remotes/origin/foo-commit
error: refs/remotes/origin/feature/gtkbmptiledviewer2 does not point to a valid object!

Please do you still have this commit?  If yes, please immediately do

git checkout -b save-the-world a9da257bf9f57fdbfd0f400b30080abc4d582ec1

so that this commit gets referenced (and not lost with the next git gc),
and then just create a tarball of your .git, and upload it for us
somewhere - we'll extract the needed object files from there, and put to
gerrit's git...

Thank you a lot,
Kendy