From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Davide Berardi <davide.berardi6@unibo.it>,
"git\@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: [PATCH v2] clone: Don't segfault on -b specifing a non-commit
Date: Wed, 06 Nov 2019 10:36:18 +0900 [thread overview]
Message-ID: <xmqqbltpyeel.fsf@gitster-ct.c.googlers.com> (raw)
In-Reply-To: <20191105043749.GA27601@sigill.intra.peff.net> (Jeff King's message of "Mon, 4 Nov 2019 23:37:49 -0500")
Jeff King <peff@peff.net> writes:
> I like the logic flow in this function, which is IMHO clearer than the
> existing code. But the "err" thing puzzled me for a moment. I think you
> are trying to tell the difference between the case that both "our" and
> "remote" are NULL, and the case that we saw a non-commit. In either case
> we return NULL, but only one is an error.
Yup.
> But:
>
> - I don't think that logic needs to extend down into
> lookup_commit_reference_gently(); a NULL return from it would always
> be an error, wouldn't it?
Yes.
> - we could probably simplify this by just inlining it into
> update_head(). Something like:
>
> if (our)
> tip = &our->old_oid;
> else if (remote)
> tip = &remote->old_oid;
>
> if (!tip) {
> /*
> * We have no local branch requested with "-b", and the
> * remote HEAD is unborn. There's nothing to update HEAD
> * to, but this state is not an error.
> */
> return 0;
> }
I somehow had an impression that Davide was protecting against the
case where tip->old_oid is null_oid (cloning from an empty repo?);
NULL return from lookup_commit_reference_gently(null_oid) would not
deserve a warning from this codepath, and should work just like the
way it has worked before these changes.
> tip_commit = lookup_commit_reference_gently(...);
> if (!tip_commit) {
> /*
>> - fetch_if_missing = 1;
>> - err = checkout(submodule_progress);
>> + if (!err) {
>> + fetch_if_missing = 1;
>> + err = checkout(submodule_progress);
>> + }
>
> This part makes sense. We might want an explanatory comment along the
> lines of:
>
> /*
> * Only try to checkout if we successfully updated HEAD; otherwise
> * HEAD isn't pointing to the thing the user wanted.
> /
> if (!err) {
> ...
Yup.
>> diff --git a/t/t5609-clone-branch.sh b/t/t5609-clone-branch.sh
>
> I think it would be the case that the remote HEAD is pointing to a
> non-commit (since that's a corrupt repository, it might make sense
> create a separate sub-repository).
All good comments.
Thanks
next prev parent reply other threads:[~2019-11-06 1:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 0:24 [PATCH] Segmentation Fault on non-commit --branch clone Davide Berardi
2019-11-01 19:08 ` Johannes Schindelin
2019-11-01 19:35 ` Jeff King
2019-11-02 10:16 ` Junio C Hamano
2019-11-03 18:16 ` Davide Berardi
2019-11-04 3:55 ` Junio C Hamano
2019-11-02 9:18 ` Junio C Hamano
2019-11-01 19:43 ` Jeff King
2019-11-02 10:07 ` Junio C Hamano
2019-11-03 18:07 ` [PATCH v2] clone: Don't segfault on -b specifing a non-commit Davide Berardi
2019-11-05 4:37 ` Jeff King
2019-11-06 1:36 ` Junio C Hamano [this message]
2019-11-06 4:05 ` Jeff King
2019-11-06 9:53 ` Junio C Hamano
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