Re: [PATCH v3 14/21] read-cache: touch shared index files when used

> Also in general the split-index mode is useful when you often write
> new indexes, and in this case shared index files that are used will
> often be freshened, so the risk of deleting interesting shared index
> files should be low.
> ...
>> Not that I think freshening would actually fail in a repository
>> where you can actually write into to update the index or its refs to
>> make a difference (iow, even if we make it die() loudly when shared
>> index cannot be "touched" because we are paranoid, no real life
>> usage will trigger that die(), and if a repository does trigger the
>> die(), I think you would really want to know about it).
>
> As I wrote above, I think if we can actually write the shared index
> file but its freshening fails, it probably means that the shared index
> file has been removed behind us, and this case is equivalent as when
> loose files have been removed behind us.