Subject: Re: [PATCH v3 1/5] merge-tree: fail with a non-zero exit code on missing tree objects

From: Junio C Hamano <[email-masked]>
Date: Thu, 22 Feb 2024 09:13:22 -0800

"Johannes Schindelin via GitGitGadget" <[email-masked]>
writes:

> -	parse_tree(merge_base);
> -	parse_tree(side1);
> -	parse_tree(side2);
> +	if (parse_tree(merge_base) < 0 ||
> +	    parse_tree(side1) < 0 ||
> +	    parse_tree(side2) < 0)
> +		return -1;

Obviously good.

> diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
> index 7d0fa74da74..908c9b540c8 100755
> --- a/t/t4301-merge-tree-write-tree.sh
> +++ b/t/t4301-merge-tree-write-tree.sh
> @@ -951,4 +951,15 @@ test_expect_success '--merge-base with tree OIDs' '
>  	test_cmp with-commits with-trees
>  '
>  
> +test_expect_success 'error out on missing tree objects' '
> +	git init --bare missing-tree.git &&
> +	git rev-list side3 >list &&
> +	git rev-parse side3^: >>list &&
> +	git pack-objects missing-tree.git/objects/pack/side3-tree-is-missing <list &&
> +	side3=$(git rev-parse side3) &&
> +	test_must_fail git --git-dir=missing-tree.git merge-tree $side3^ $side3 >actual 2>err &&
> +	test_grep "Could not read $(git rev-parse $side3:)" err &&
> +	test_must_be_empty actual
> +'

I very much like the way this test emulates an operation in a
repository that lack certaion objects so cleanly, and wish we
had used this pattern instead of poking at loose object files
in hundreds of existing tests (#leftoverbits obviously).

It also justifies why a silent "return -1" in the patch is
sufficient ;-)

Thanks.