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

From: Junio C Hamano <[email-masked]>
Date: Mon, 23 Jan 2017 10:53:39 -0800

Christian Couder <[email-masked]> writes:

> 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.

OK, so it is unlikely to happen, and when it happens it leads to a
catastrophic failure---do we just ignore or do we report an error?