Re: [PATCH v6 2/3] branch: add flags and config to inherit tracking

[Glen Choo <chooglen@google.com>]

Josh Steadmon <steadmon@google.com> writes:

> @@ -192,11 +220,15 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
>  			   enum branch_track track, int quiet)
>  {
>  	struct tracking tracking;
> +	struct string_list tracking_srcs = STRING_LIST_INIT_DUP;
>  	int config_flags = quiet ? 0 : BRANCH_CONFIG_VERBOSE;
>  
>  	memset(&tracking, 0, sizeof(tracking));
>  	tracking.spec.dst = (char *)orig_ref;
> -	if (for_each_remote(find_tracked_branch, &tracking))
> +	tracking.srcs = &tracking_srcs;
> +	if (track != BRANCH_TRACK_INHERIT)
> +		for_each_remote(find_tracked_branch, &tracking);
> +	else if (inherit_tracking(&tracking, orig_ref))
>  		return;
>  
>  	if (!tracking.matches)
> @@ -204,6 +236,7 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
>  		case BRANCH_TRACK_ALWAYS:
>  		case BRANCH_TRACK_EXPLICIT:
>  		case BRANCH_TRACK_OVERRIDE:
> +		case BRANCH_TRACK_INHERIT:
>  			break;
>  		default:
>  			return;
> @@ -213,11 +246,13 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
>  		die(_("Not tracking: ambiguous information for ref %s"),
>  		    orig_ref);
>  
> -	if (install_branch_config(config_flags, new_ref, tracking.remote,
> -			      tracking.src ? tracking.src : orig_ref) < 0)
> +	if (tracking.srcs->nr < 1 && track != BRANCH_TRACK_INHERIT)
> +		string_list_append(tracking.srcs, orig_ref);

So, in the BRANCH_TRACK_{ALWAYS,EXPLICIT,OVERRIDE} cases, we append
orig_ref because we expect orig_ref to be a local ref that the caller
wants to track. This is not the case with BRANCH_TRACK_INHERIT, where we
want to inherit the configuration and we no longer care about orig_ref.

This is correct, though it's more unobvious than what I originally
envisioned when I commented on [1]. As a small nit, it might benefit
from a clarifying comment, but this is fine as it is :)

> diff --git a/t/t2027-checkout-track.sh b/t/t2027-checkout-track.sh
> index 4453741b96..49c7def21c 100755
> --- a/t/t2027-checkout-track.sh
> +++ b/t/t2027-checkout-track.sh
> @@ -24,4 +24,27 @@ test_expect_success 'checkout --track -b rejects an extra path argument' '
>  	test_i18ngrep "cannot be used with updating paths" err
>  '
>  
> +test_expect_success 'checkout --track -b overrides autoSetupMerge=inherit' '
> +	# Set up tracking config on main
> +	test_config branch.main.remote origin &&
> +	test_config branch.main.merge refs/heads/main &&
> +	test_config branch.autoSetupMerge inherit &&
> +	# With --track=inherit, we copy the tracking config from main
> +	git checkout --track=inherit -b b1 main &&
> +	test_cmp_config origin branch.b1.remote &&
> +	test_cmp_config refs/heads/main branch.b1.merge &&
> +	# With branch.autoSetupMerge=inherit, we do the same
> +	git checkout -b b2 main &&
> +	test_cmp_config origin branch.b2.remote &&
> +	test_cmp_config refs/heads/main branch.b2.merge &&
> +	# But --track overrides this
> +	git checkout --track -b b3 main &&
> +	test_cmp_config . branch.b3.remote &&
> +	test_cmp_config refs/heads/main branch.b3.merge &&
> +	# And --track=direct does as well
> +	git checkout --track=direct -b b4 main &&
> +	test_cmp_config . branch.b4.remote &&
> +	test_cmp_config refs/heads/main branch.b4.merge

Nit: in both cases, the expected result is that branch.b*.merge is
"refs/heads/main". so the difference between --track=direct and
--track=inherit would be more obvious if main tracked something other
than origin/main.

As an side, the comments in the tests make it really readable :)

Overall this patch looks good.

[1] https://lore.kernel.org/git/kl6lfsr3c3j7.fsf@chooglen-macbookpro.roam.corp.google.com