Re: [PATCH] fast-export: Allow pruned-references in mark file

> fast-export can fail because of some pruned-reference when importing a
> mark file.
>
> The problem happens in the following scenario:
>
>     $ git fast-export --export-marks=MARKS master
>     (rewrite master)
>     $ git prune
>     $ git fast-export --import-marks=MARKS master
>
> This might fail if some references have been removed by prune
> because some marks will refer to no longer existing commits.
> git-fast-export will not need these objects anyway as they were no
> longer reachable.
>
> We still need to update last_numid so we don't change the mapping
> between marks and objects for remote-helpers.
> Unfortunately, the mark file should not be rewritten without lost marks
> if no new objects has been exported, as we could lose track of the last
> last_numid.