Subject: Re: [PATCH v2 7/8] for-each-ref: add ahead-behind format atom

From: Junio C Hamano <[email-masked]>
Date: Fri, 10 Mar 2023 11:09:00 -0800

"Derrick Stolee via GitGitGadget" <[email-masked]> writes:

> Test                                            this tree
> ---------------------------------------------------------------
> 1500.2: ahead-behind counts: git for-each-ref   0.27(0.24+0.02)
> 1500.3: ahead-behind counts: git branch         0.27(0.24+0.03)
> 1500.4: ahead-behind counts: git tag            0.28(0.27+0.01)
> 1500.5: ahead-behind counts: git rev-list       4.57(4.03+0.54)
>
> The 'git rev-list' test exists in this change as a demonstration, but it
> will be removed in the next change to avoid wasting time on this
> comparison.

Nice.

> +ahead-behind:<ref>::
> +	Two integers, separated by a space, demonstrating the number of
> +	commits ahead and behind, respectively, when comparing the output
> +	ref to the `<ref>` specified in the format.

Don't we take any commit-ish, not necessarily a ref?  In the context
of for-each-ref documentation, I am afraid that the readers assume
that the word refers to a ref and %(ahead-behind:ea6e93913b) and the
like are forbidden, which is not what you wanted when you used
lookup_commit_reference_by_name() in the implementation.

> +	# Use " !" at the end to demonstrate whitepsace

psace.

> +	# around empty ahead-behind token for tag-blob.

;-)

> +	cat >expect <<-EOF &&
> +	refs/tags/tag-blob  !
> +	refs/tags/tag-left 1 1 !
> +	refs/tags/tag-lines 0 1 !
> +	refs/tags/tag-one-line 0 1 !
> +	refs/tags/tag-right 0 0 !
> +	refs/tags/tag-zero-lines 0 1 !
> +	EOF
> +	git tag -l --format="%(refname) %(ahead-behind:HEAD) !" >actual 2>err &&
> +	grep "refs/tags/tag" actual >actual.focus &&
> +	test_cmp expect actual.focus &&
> +
> +	# Error reported for tags that point to non-commits.
> +	grep "error: object [0-9a-f]* is a blob, not a commit" err
> +'
> +
>  # trying to verify annotated non-signed tags:
>  
>  test_expect_success GPG \