Re: [PATCH 2/2] fsck: report errors if reflog entries point at invalid objects

> On Mon, Jun 08, 2015 at 06:00:09PM +0200, Johannes Schindelin wrote:
> 
>> >> I like the idea, but I am a bit uncertain whether it would constitute
>> >> "too backwards-incompatible" a change to make this an error. I think
>> >> it could be argued both ways: it *is* an improvement, but it could
>> >> also possibly disrupt scripts that work pretty nicely at the moment.
>> >
>> > What kind of script are you worried about?
>>
>> I was concerned about scripts that work on repositories whose reflogs
>> become inconsistent for whatever reason (that happened a lot to me in
>> the past, IIRC it had something to do with bare repositories and/or
>> shared object databases).
> 
> I think these repositories are already broken. You cannot run `git gc`
> in such a repository, as it will barf when trying to walk the reflog
> tips during `git repack`.
> 
> We run into this exact situation at GitHub because of our shared object
> databases. Our per-fork repack code basically has to do:
> 
>   if ! git repack ...; then
>     git reflog expire --expire-unreachable=all --all &&
>     git repack ... ||
>     die "ok, it really is broken"
>   fi