Re: [PATCH 09/13] t: add lib-loose.sh

[Patrick Steinhardt <ps@pks.im>]

On Fri, May 16, 2025 at 12:50:02AM -0400, Jeff King wrote:
> This commit adds a shell library for writing raw loose objects into the
> object database. Normally this is done with hash-object, but the
> specific intent here is to allow broken objects that hash-object may not
> support.
> 
> We'll convert several cases that use "hash-object --literally" to write
> objects with invalid types. That works currently, but dropping this
> dependency will allow us to remove that feature and simplify the
> object-writing code.
> 
> Signed-off-by: Jeff King <peff@peff.net>
> ---
>  t/lib-loose.sh                      | 30 +++++++++++++++++++++++++++++
>  t/t1006-cat-file.sh                 |  5 +++--
>  t/t1450-fsck.sh                     |  3 ++-
>  t/t1512-rev-parse-disambiguation.sh |  5 +++--
>  4 files changed, 38 insertions(+), 5 deletions(-)
>  create mode 100644 t/lib-loose.sh
> 
> diff --git a/t/lib-loose.sh b/t/lib-loose.sh
> new file mode 100644
> index 0000000000..3613631eaf
> --- /dev/null
> +++ b/t/lib-loose.sh
> @@ -0,0 +1,30 @@
> +# Support routines for hand-crafting loose objects.
> +
> +# Write a loose object into the odb at $1, with object type $2 and contents
> +# from stdin. Writes the oid to stdout. Example:
> +#
> +#   oid=$(echo foo | loose_obj .git/objects blob)
> +#
> +loose_obj () {

Nit: I would have called this `write_loose_obj ()` to indicate that it's
writing an object. But ultimately doesn't matter too much, so please
feel free to ignore this comment.

> +	cat >tmp_loose.content &&
> +	size=$(wc -c <tmp_loose.content) &&
> +	{
> +		# Do not quote $size here; we want the shell
> +		# to strip whitespace that "wc" adds on some platforms.
> +		printf "%s %s\0" "$2" $size &&
> +		cat tmp_loose.content
> +	} >tmp_loose.raw &&
> +
> +	oid=$(test-tool $test_hash_algo <tmp_loose.raw) &&
> +	suffix=${oid#??} &&
> +	prefix=${oid%$suffix} &&
> +	dir=$1/$prefix &&
> +	file=$dir/$suffix &&
> +
> +	test-tool zlib deflate <tmp_loose.raw >tmp_loose.zlib &&
> +	mkdir -p "$dir" &&
> +	mv tmp_loose.zlib "$file" &&
> +
> +	rm tmp_loose.raw tmp_loose.content &&
> +	echo "$oid"
> +}

All of this look sensible to me.

Patrick