Re: [PATCH v2] send-email: export patch counters in validate environment

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 12, 2023, 17:53 UTC
Message-ID: <xmqqfs957zs4.fsf@gitster.g>
In-Reply-To: <20230412095434.140754-1-robin@jarry.cc>

Robin Jarry <robin@jarry.cc> writes:

>  if ($validate) {
> +	# FIFOs can only be read once, exclude them from validation.

It is very good to see this comment here, as it may not be obvious to everybody why we exclude them.

> +validate_cover_letter()
> +{

See Documentation/CodingGuidelines, look for "For shell scripts specifically" and follow what is in the section. There may be style violations of other kinds in the file.

Show 5 quoted lines

> +validate_patch()
> +{
> +	file="$1"
> +	# Ensure that the patch applies without conflicts to the latest
> +	# upstream version.

That comment is true only for the first one. The second patch needs to apply to the upstream plus the first patch, and so on.

Show 38 quoted lines

> +	git am -3 "$file" || die "failed to apply patch on upstream repo"
> +	# XXX: Add appropriate checks here (e.g. checkpatch.pl).
> +}
> +
> +validate_series()
> +{
> +	# XXX: Add appropriate checks here (e.g. quick build, etc.).
> +}
> +
> +die()
> +{
> +	echo "sendemail-validate: error: $*" >&2
> +	exit 1
> +}
> +
> +get_work_dir()
> +{
> +	git config --get sendemail.validateWorkdir || {
> +		# Initialize it to a temp dir, if unset.
> +		git config --add sendemail.validateWorkdir "$(mktemp -d)"
> +		git config --get sendemail.validateWorkdir
> +	}
> +}
> +
> +get_upstream_url()
> +{
> +	git config --get remote.origin.url ||
> +		die "cannot get remote.origin.url"
> +}
> +
> +clone_upstream()
> +{
> +	workdir="$1"
> +	url="$(get_upstream_url)"
> +	rm -rf -- "$workdir"
> +	git clone --depth=1 "$url" "$workdir" ||
> +		die "failed to clone upstream repository"
> +}

Style-wise, it is better to get rid of get_upstream_url and write the above more like

	workdir=$1 &&
	url=$(git config remote.originurl) &&
	rm -r -- "$workdir" &&
	git clone ... ||
	die "failed to ..."

and that would be less error prone (e.g. you will catch failure from "rm" yourself, instead of relying on "git clone" to catch it for you).

In any case, I would avoid network traffic and extra disk usage if I were showing an example for readers to follow, and would not recommend you to use "clone" here, even if it were a shallow one.

It would make much more sense to create a secondary worktree based on this repository, with its HEAD detached at the copy of the target branch (e.g. refs/remotes/origin/HEAD), and use that secondary worktree, as the necessary objects for "am -3" to fall back on are more likely to be found in such a setting, compared to a shallow clone that only can have the blobs at the tip.

> +
> +# main -------------------------------------------------------------------------

Show 6 quoted lines

> +workdir=$(get_work_dir)
> +if [ "$GIT_SENDEMAIL_FILE_COUNTER" = 1 ]; then
> +	clone_upstream "$workdir"
> +fi
> +cd "$workdir"
> +export GIT_DIR="$workdir/.git"

It is a good discipline to always set GIT_DIR and GIT_WORK_TREE as a pair. Working in a subdirectory of a working tree becomes awkward, because the presence of the former without the latter signals that your $(cwd) is at the top of the working tree.

But that is more or less moot, because I am suggesting not to use "git clone" to prepare the playground and instead use a secondary worktree that is attached to the same current repository, so GIT_DIR would be the same as the current one.

And because you are "cd"ing there anyway, it probably is much simpler to just

    unset GIT_DIR GIT_WORK_TREE

to let the repository discovery mechanism take care of it.

Show 9 quoted lines

> +if grep -q "^diff --git " "$1"; then
> +	validate_patch "$1"
> +else
> +	validate_cover_letter "$1"
> +fi
> +
> +if [ "$GIT_SENDEMAIL_FILE_COUNTER" = "$GIT_SENDEMAIL_FILE_TOTAL" ]; then
> +	validate_series || die "patch series was rejected"
> +fi

It is uneven that validate_patch and validate_cover_letter are responsible for dying when problem is found, but validate_series is not and the caller is made responsible for that.

I would make the caller responsible for dying with message for all three by removing the calls to "die" or "exit" from the former two, if I were showing an example for readers to follow.

Overall, a very well crafted patch, even though little details and some design choices can be improved.

Thanks.