From: Phillip Wood <phillip.wood123@gmail.com>
Date: Thu, 24 Sep 2026 09:42:09 GMT
Subject: Re: [PATCH v2 4/4] builtin/stash: merge index in-core
Message-ID: <68e83baa-6ccb-4ca8-a1df-f09d51749c67@gmail.com>
In-Reply-To: <e49936ee12aaf5d82a98dddcc618cee01ac3c681.1790168285.git.ben.knoble@gmail.com>

Hi Ben

I've spotted a memory leak that I missed last time, apart from that this 
looks good.

On 23/09/2026 13:58, D. Ben Knoble wrote:
> @@ -671,29 +627,27 @@ static enum stash_apply_result do_apply_stash(const char *prefix,
>   		    oideq(&c_tree, &info->i_tree)) {
>   			has_index = 0;
>   		} else {
> -			struct strbuf out = STRBUF_INIT;
> +			struct merge_result result = { 0 };
>   
> -			if (diff_tree_binary(&out, &info->w_commit)) {
> -				strbuf_release(&out);
> -				return error(_("could not generate diff %s^!."),
> -					     oid_to_hex(&info->w_commit));
> -			}
> +			o.branch1 = "Upstream index";

This is the current index, calling it "upstream" is a bit confusing to 
me but that's not worth a re-roll on its own.

> +			o.branch2 = "Stashed index changes";
> +			o.ancestor = "Stash base";
>   
> -			ret = apply_cached(&out);
> -			strbuf_release(&out);
> -			if (ret)
> +			o.verbosity = 0;
> +
> +			head = lookup_tree(o.repo, &c_tree);
> +			merge = lookup_tree(o.repo, &info->i_tree);
> +			merge_base = lookup_tree(o.repo, &info->b_tree);
> +
> +			merge_incore_nonrecursive(&o, head, merge, merge_base,
> +						  &result);
> +
> +			if (!result.clean)
>   				return error(_("conflicts in index. "
>   					       "Try without --index."));

Sorry, I missed this last time, but we should finalize the merge before 
returning to ensure the allocations in result are freed.
Everything else looks fine.

Thanks

Phillip

> -			discard_index(the_repository->index);
> -			repo_read_index(the_repository);
> -			if (write_index_as_tree(&index_tree, the_repository->index,
> -						repo_get_index_file(the_repository), 0, NULL))
> -				return error(_("could not save index tree"));
> -
> -			reset_head();
> -			discard_index(the_repository->index);
> -			repo_read_index(the_repository);
> +			oidcpy(&index_tree, &result.tree->object.oid);
> +			merge_finalize(&o, &result);
>   		}
>   	}
>   
> diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
> index 64fe21717d..8f6109fb91 100755
> --- a/t/t7600-merge.sh
> +++ b/t/t7600-merge.sh
> @@ -801,6 +801,15 @@ verify_no_mergehead () {
>   	test_cmp result.1-5 file
>   '
>   
> +test_expect_success 'fast-forward merge with --autostash, stash.index' '
> +	git reset --hard c0 &&
> +	git stash clear &&
> +	echo staged >>z && git add z &&
> +	git -c stash.index=true merge --autostash c1 2>err &&
> +	test_grep "Applied autostash." err &&
> +	test_stdout_line_count = 0 git stash list
> +'
> +
>   test_expect_success 'failed fast-forward merge with --autostash' '
>   	git reset --hard c0 &&
>   	git merge-file file file.orig file.5 &&