Subject: Re: [PATCH] pull: should be noop when already-up-to-date

From: Junio C Hamano <[email-masked]>
Date: Thu, 18 Nov 2021 15:50:58 -0800

"Erwin Villejo via GitGitGadget" <[email-masked]> writes:

> From: Erwin Villejo <[email-masked]>
>
> The already-up-to-date pull bug was fixed for --ff-only but it did not
> include the case where --ff or --ff-only are not specified. This updates
> the --ff-only fix to include the case where --ff or --ff-only are not
> specified in command line flags or config.
>
> Signed-off-by: Erwin Villejo <[email-masked]>
> ---

> @@ -1102,15 +1103,16 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
>  	}
>  
>  	can_ff = get_can_ff(&orig_head, &merge_heads);
> +	divergent = !can_ff && !already_up_to_date(&orig_head, &merge_heads);
>  
>  	/* ff-only takes precedence over rebase */
>  	if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
> -		if (!can_ff && !already_up_to_date(&orig_head, &merge_heads))
> +		if (divergent)
>  			die_ff_impossible();
>  		opt_rebase = REBASE_FALSE;
>  	}
>  	/* If no action specified and we can't fast forward, then warn. */
> -	if (!opt_ff && rebase_unspecified && !can_ff) {
> +	if (!opt_ff && rebase_unspecified && divergent) {
>  		show_advice_pull_non_ff();
>  		die(_("Need to specify how to reconcile divergent branches."));
>  	}

Looks correct.  I wonder if there is a simplify these two checks,
but let's keep the original code structure for now in this step,
which is about correctness.

Will apply.  Thanks.

> diff --git a/t/t7601-merge-pull-config.sh b/t/t7601-merge-pull-config.sh
> index 6275641b9c2..bd238d89b0c 100755
> --- a/t/t7601-merge-pull-config.sh
> +++ b/t/t7601-merge-pull-config.sh
> @@ -387,6 +387,12 @@ test_expect_success 'pull prevents non-fast-forward with "only" in pull.ff' '
>  	test_must_fail git pull . c3
>  '
>  
> +test_expect_success 'already-up-to-date pull succeeds with unspecified pull.ff' '
> +	git reset --hard c1 &&
> +	git pull . c0 &&
> +	test "$(git rev-parse HEAD)" = "$(git rev-parse c1)"
> +'
> +
>  test_expect_success 'already-up-to-date pull succeeds with "only" in pull.ff' '
>  	git reset --hard c1 &&
>  	test_config pull.ff only &&
>
> base-commit: cd3e606211bb1cf8bc57f7d76bab98cc17a150bc