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

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 7, 2017, 21:46 UTC
Message-ID: <xmqqo9zi35n6.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CAP8UFD1EgOxcPi=tpiosKkYMcCZe+b6gwW0CKt2sE1NZ7gQv=A@mail.gmail.com>

Christian Couder <christian.couder@gmail.com> writes:

> So what should we do if freshen_file() returns 0 which means that the
> freshening failed?

You tell me ;-)  as you are the one who is proposing this feature.

Isn't a failure to freshen it a grave error? We are letting a base/shared index file that is known to be in-use go stale and eventually subject for garbage collection, and the user should be notified in some way before the actual GC happens that renders the index file unusable?

What is the failure mode after such a premature GC happens? What does the end-user see? Can you try to (1) split the index (2) modify bunch of entries (3) remove the base/shared index with /bin/rm and then see how various Git commands fail? Do they fail gracefully?

I am trying to gauge the seriousness of ignoring such an error here.