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Re: [PATCH] push: avoid showing false negotiation errors

From
Jeff King <peff@peff.net>
Date
Jul 2, 2024, 21:11 UTC
Message-ID
<20240702211151.GA120950@coredump.intra.peff.net>
In-Reply-To
<xmqqo77fr2h0.fsf@gitster.g>
On Tue, Jul 02, 2024 at 12:57:47PM -0700, Junio C Hamano wrote:
Show 14 quoted lines
> When "git push" is configured to use the push negotiation, a push of
> deletion of a branch (without pushing anything else) may end up not
> having anything to negotiate for the common ancestor discovery.
> 
> In such a case, we end up making an internal invocation of "git
> fetch --negotiate-only" without any "--negotiate-tip" parameters
> that stops the negotiate-only fetch from being run, which by itself
> is not a bad thing (one fewer round-trip), but the end-user sees a
> "fatal: --negotiate-only needs one or more --negotiation-tip=*"
> message that the user cannot act upon.
> 
> Teach "git push" to notice the situation and omit performing the
> negotiate-only fetch to begin with.  One fewer process spawned, one
> fewer "alarming" message given the user.
Makes sense.
Show 25 quoted lines
> @@ -427,17 +427,26 @@ static void get_commons_through_negotiation(const char *url,
>  	struct child_process child = CHILD_PROCESS_INIT;
>  	const struct ref *ref;
>  	int len = the_hash_algo->hexsz + 1; /* hash + NL */
> +	int nr_negotiation_tip = 0;
>  
>  	child.git_cmd = 1;
>  	child.no_stdin = 1;
>  	child.out = -1;
>  	strvec_pushl(&child.args, "fetch", "--negotiate-only", NULL);
>  	for (ref = remote_refs; ref; ref = ref->next) {
> -		if (!is_null_oid(&ref->new_oid))
> -			strvec_pushf(&child.args, "--negotiation-tip=%s", oid_to_hex(&ref->new_oid));
> +		if (!is_null_oid(&ref->new_oid)) {
> +			strvec_pushf(&child.args, "--negotiation-tip=%s",
> +				     oid_to_hex(&ref->new_oid));
> +			nr_negotiation_tip++;
> +		}
>  	}
>  	strvec_push(&child.args, url);
>  
> +	if (!nr_negotiation_tip) {
> +		child_process_clear(&child);
> +		return;
> +	}

OK, this works as advertised. "nr_negotiation_tip" is really a boolean here, as we never care about the actual count. I'd probably have written it as "have_negotiation_tip = 1", but I don't think there is any real reason to prefer one over the other.

And we can't just check for a non-NULL remote_refs, since we are looking for non-deletions.

Show 18 quoted lines
> diff --git c/t/t5516-fetch-push.sh w/t/t5516-fetch-push.sh
> index 2e7c0e1648..a3f18404d9 100755
> --- c/t/t5516-fetch-push.sh
> +++ w/t/t5516-fetch-push.sh
> @@ -230,6 +230,17 @@ test_expect_success 'push with negotiation proceeds anyway even if negotiation f
>  	test_grep "push negotiation failed" err
>  '
>  
> +test_expect_success 'push deletion with negotiation' '
> +	mk_empty testrepo &&
> +	git push testrepo $the_first_commit:refs/heads/master &&
> +	git ls-remote testrepo >ls-remote &&
> +	git -c push.negotiate=1 push testrepo \
> +		:master $the_first_commit:refs/heads/next 2>errors-2 &&
> +	test_grep ! "negotiate-only needs one or " errors-2 &&
> +	git -c push.negotiate=1 push testrepo :next 2>errors-1 &&
> +	test_grep ! "negotiate-only needs one or " errors-1
> +'

The test mostly makes sense, though is the ls-remote bit leftover debugging cruft?

-Peff
Previous: Junio C HamanoNext: Junio C Hamano
Message 2 of 3 in “push: avoid showing false negotiation errors”
  1. push: avoid showing false negotiation errorsJunio C Hamano, Jul 2, 2024
  2. Jeff KingJul 2, 2024
  3. Junio C HamanoJul 2, 2024

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