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Re: [PATCH v3] tracking branches: add advice to ambiguous refspec error

From
Junio C Hamano <gitster@pobox.com>
Date
Mar 28, 2022, 16:23 UTC
Message-ID
<xmqqwnge2ghe.fsf@gitster.g>
In-Reply-To
<pull.1183.v3.git.1648450268285.gitgitgadget@gmail.com>
"Tao Klerks via GitGitGadget" <gitgitgadget@gmail.com> writes:
Show 6 quoted lines
> From: Tao Klerks <tao@klerks.biz>
>
> The error "not tracking: ambiguous information for ref" is raised
> when we are evaluating what tracking information to set on a branch,
> and find that the ref to be added as tracking branch is mapped
> under multiple remotes' fetch refspecs.
OK.
Show 18 quoted lines
>  Documentation/config/advice.txt |  4 +++
>  advice.c                        |  1 +
>  advice.h                        |  1 +
>  branch.c                        | 44 +++++++++++++++++++++++++++++----
>  4 files changed, 45 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
> index c40eb09cb7e..90f7dbd03aa 100644
> --- a/Documentation/config/advice.txt
> +++ b/Documentation/config/advice.txt
> @@ -4,6 +4,10 @@ advice.*::
>  	can tell Git that you do not need help by setting these to 'false':
>  +
>  --
> +	ambiguousFetchRefspec::
> +		Advice shown when branch tracking relationship setup fails due
> +		to multiple remotes' refspecs mapping to the same remote
> +		tracking namespace in the repo.
	Advice shown when fetch refspec for multiple remotes map to
	the same remote-tracking branch namespace and causes branch
	tracking set-up to fail.

"remote-tracking" should be spelled as a single word. There are some existing mistakes in the code, but let's not make it worse.

Show 36 quoted lines
> diff --git a/branch.c b/branch.c
> index 6b31df539a5..5c28d432103 100644
> --- a/branch.c
> +++ b/branch.c
> @@ -18,9 +18,15 @@ struct tracking {
>  	int matches;
>  };
>  
> +struct find_tracked_branch_cb {
> +	struct tracking *tracking;
> +	struct strbuf remotes_advice;
> +};
> +
>  static int find_tracked_branch(struct remote *remote, void *priv)
>  {
> -	struct tracking *tracking = priv;
> +	struct find_tracked_branch_cb *ftb = priv;
> +	struct tracking *tracking = ftb->tracking;
>  
>  	if (!remote_find_tracking(remote, &tracking->spec)) {
>  		if (++tracking->matches == 1) {
>  			string_list_append(tracking->srcs, tracking->spec.src);
>  			tracking->remote = remote->name;
>  		} else {
>  			free(tracking->spec.src);
>  			string_list_clear(tracking->srcs, 0);
>  		}
> +		/*
> +		 * TRANSLATORS: This is a line listing a remote with duplicate
> +		 * refspecs, to be later included in advice message
> +		 * ambiguousFetchRefspec. For RTL languages you'll probably want
> +		 * to swap the "%s" and leading "  " space around.
> +		 */
> +		strbuf_addf(&ftb->remotes_advice, _("  %s\n"), remote->name);
>  		tracking->spec.src = NULL;
>  	}

This is wasteful. remotes_advice does not have to be filled when we are not going to give advice, i.e. there is only one matching remote and no second or subsequent ones, which should be the majority case. And we should not make majority of users who do not make a mistake that needs the advice message pay the cost of giving advice to those who screw up, if we can avoid it.

Instead, only when we are looking at the second one, we can stuff tracking->remote (i.e. the first one) to remotes_advice, and then append remote->name there. Perhaps we can do it like so?

	struct strbuf *names = &ftb->remotes_advice;
	const char *namefmt = N_("  %s\n");
	switch (++tracking->matches) {
	case 1:
		string_list_append(tracking->srcs, tracking->spec.src);
		tracking->remote = remote->name;
		break;
	case 2:
		strbuf_addf(names, _(namefmt), tracking->remote);
		/* fall through */
	default:
		strbuf_addf(names, _(namefmt), remote->name);
                free(tracking->spec.src);
                string_list_clear(tracking->srcs, 0);
                break;
	}
	tracking->spec.src = NULL;

For a bonus point, remotes_advice member can be left empty without paying the cost to strbuf_addf() when the advice configuration says we are not going to show the message.

Thanks.
Previous: Tao Klerks via GitGitGadgetNext: Glen Choo
Message 7 of 36 in “tracking branches: add advice to ambiguous refspec error”
  1. tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Mar 21, 2022
  2. Ævar Arnfjörð BjarmasonMar 21, 2022
  3. Tao KlerksMar 22, 2022
  4. RFC: tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Mar 22, 2022
  5. Ævar Arnfjörð BjarmasonMar 22, 2022
  6. tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Mar 28, 2022
  7. Junio C HamanoMar 28, 2022
  8. Glen ChooMar 28, 2022
  9. Junio C HamanoMar 28, 2022
  10. Tao KlerksMar 28, 2022
  11. Ævar Arnfjörð BjarmasonMar 28, 2022
  12. Junio C HamanoMar 28, 2022
  13. Junio C HamanoMar 28, 2022
  14. Tao KlerksMar 29, 2022
  15. tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Mar 29, 2022
  16. Tao KlerksMar 29, 2022
  17. Junio C HamanoMar 29, 2022
  18. Tao KlerksMar 30, 2022
  19. tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Mar 30, 2022
  20. Ævar Arnfjörð BjarmasonMar 30, 2022
  21. Tao KlerksMar 30, 2022
  22. Tao KlerksMar 30, 2022
  23. Ævar Arnfjörð BjarmasonMar 30, 2022
  24. Junio C HamanoMar 30, 2022
  25. Ævar Arnfjörð BjarmasonMar 30, 2022
  26. Junio C HamanoMar 30, 2022
  27. Ævar Arnfjörð BjarmasonMar 30, 2022
  28. tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Mar 31, 2022
  29. Junio C HamanoMar 31, 2022
  30. Glen ChooMar 31, 2022
  31. Tao KlerksApr 1, 2022
  32. Glen ChooApr 1, 2022
  33. Junio C HamanoMar 31, 2022
  34. tracking branches: add advice to ambiguous refspec errorTao Klerks via GitGitGadget, Apr 1, 2022
  35. Glen ChooApr 1, 2022
  36. Junio C HamanoApr 1, 2022

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