Re: [PATCH v2] branch: do not fail a no-op --edit-desc

From: Junio C Hamano <gitster@pobox.com>
Date: Sep 30, 2022, 18:13 UTC
Message-ID: <xmqqill4k9wr.fsf@gitster.g>
In-Reply-To: <220930.861qrsvj12.gmgdl@evledraar.gmail.com>

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

Show 6 quoted lines

>> Ah, OK, so in short, _gently() is still unusable to use for that.  I
>> guess it means that the approach taken by v1 would be a better
>> solution, then.
>
> As you noted it's got a TOCTOU instead, so we might wipe away good
> config entirely.

I do not think that is the case.

What you have in mind is probably something entirely different. If you open two windows, start "edit description" in both, write a description in one of them, then write a different description in another, depending on the order you save the buffer and cause the "git branch --edit-desc" that invoked the editor to use the edited result, the description written in the editor that was later closed will win, instead of telling you "you started from state X and you want to update to state Y, but in the meantime somebody else made it state Z, so I won't overwrite it with state Y". But that has always been with us, IIUC.

The only "funny" thing the change makes it do is leave the good config as-is, if the user starts without an existing branch description and exits with an empty edit buffer, instead of removing the description written in the other window in the meantime. That is quite far from wiping away good config entirely.