Re: [PATCH] t6300: don't run cat-file on non-existent object

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

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Hi Danh,

On Tue, 17 Aug 2021, Đoàn Trần Công Danh wrote:

> In t6300, some tests are guarded behind some prerequisites.
> Thus, objects created by those tests ain't available if those
> prerequisites is unsatistified.  Attempting to run "cat-file"
> on those objects will run into failure.
>
> In fact, running t6300 in an environment without gpg(1),
> we'll see those warnings:
>
> 	fatal: Not a valid object name refs/tags/signed-empty
> 	fatal: Not a valid object name refs/tags/signed-short
> 	fatal: Not a valid object name refs/tags/signed-long
>
> Let's put those commands into the real tests, in order to:
>
> * skip their execution if prerequisites aren't satistified.
> * check their exit status code
>
> Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>

Makes sense.

> ---
>  t/t6300-for-each-ref.sh | 27 ++++++++++++++++-----------
>  1 file changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
> index 9e0214076b..65fbed2bef 100755
> --- a/t/t6300-for-each-ref.sh
> +++ b/t/t6300-for-each-ref.sh
> @@ -59,18 +59,23 @@ test_atom() {
>  	# Automatically test "contents:size" atom after testing "contents"
>  	if test "$2" = "contents"
>  	then
> -		case $(git cat-file -t "$ref") in
> -		tag)
> -			# We cannot use $3 as it expects sanitize_pgp to run
> -			expect=$(git cat-file tag $ref | tail -n +6 | wc -c) ;;

Here, we pipe the output of `cat-file` to `tail` and then `wc`. But below:

> -		tree | blob)
> -			expect='' ;;
> -		commit)
> -			expect=$(printf '%s' "$3" | wc -c) ;;
> -		esac
> -		# Leave $expect unquoted to lose possible leading whitespaces
> -		echo $expect >expected
> +		expect=$(printf '%s' "$3" | wc -c)
>  		test_expect_${4:-success} $PREREQ "basic atom: $1 contents:size" '
> +			type=$(git cat-file -t "$ref") &&
> +			case $type in
> +			tag)
> +				# We cannot use $3 as it expects sanitize_pgp to run
> +				git cat-file tag $ref >out &&
> +				expect=$(<out tail -n +6 | wc -c) ;;

... we break the _first_ pipe apart, redirecting into `out` instead. I am
not sure that this patch should change that as it does, I would think that
a regular code move (with re-indentation) would be preferable.

Besides, while it is legal and works, I don't think we ever start with the
redirection. Read: it should probably be `tail -n +6 <out` instead.

> +			tree | blob)
> +				expect="" ;;
> +			commit)
> +				: "use the calculated expect" ;;

This necessarily has to be different from the original code (i.e. the code
could not have been moved verbatim) because it uses `$3`, which at this
point has a different value.

My suggestion: mention this in the commit message, other reviewers or
future readers might stumble over this otherwise.

> +			*)
> +				BUG "unknown object type" ;;

This one is new. Do we need it?

Thanks,
Dscho

> +			esac &&
> +			# Leave $expect unquoted to lose possible leading whitespaces
> +			echo $expect >expected &&
>  			git for-each-ref --format="%(contents:size)" "$ref" >actual &&
>  			test_cmp expected actual
>  		'
> --
> 2.33.0
>
>