Subject: Re: [PATCH v2] builtin/remote.c: teach `-v` to list filters for promisor remotes

From: Junio C Hamano <[email-masked]>
Date: Wed, 04 May 2022 10:10:26 -0700

"Abhradeep Chakraborty via GitGitGadget" <[email-masked]>
writes:

> diff --git a/Documentation/git-remote.txt b/Documentation/git-remote.txt
> index cde9614e362..71a0e85990d 100644
> --- a/Documentation/git-remote.txt
> +++ b/Documentation/git-remote.txt
> @@ -35,6 +35,9 @@ OPTIONS
>  -v::
>  --verbose::
>  	Be a little more verbose and show remote url after name.
> +  For promisor remotes it will show an extra information
> +  (wrapped in square brackets) describing which filter
> +  (`blob:none` etc.) that promisor remote use.
>  	NOTE: This must be placed between `remote` and subcommand.

Broken indentation.  You can save embarrassment by double checking
what you committed by sending e-mail to yourself (or checking output
from "git show") before sending it to the list.

> diff --git a/builtin/remote.c b/builtin/remote.c
> index 5f4cde9d784..d4b69fe7789 100644
> --- a/builtin/remote.c
> +++ b/builtin/remote.c
> @@ -1185,14 +1185,22 @@ static int show_push_info_item(struct string_list_item *item, void *cb_data)
>  static int get_one_entry(struct remote *remote, void *priv)
>  {
>  	struct string_list *list = priv;
> -	struct strbuf url_buf = STRBUF_INIT;
> +	struct strbuf remote_info_buf = STRBUF_INIT;
>  	const char **url;
>  	int i, url_nr;
>  
>  	if (remote->url_nr > 0) {
> -		strbuf_addf(&url_buf, "%s (fetch)", remote->url[0]);
> +		struct strbuf promisor_config = STRBUF_INIT;
> +		const char *partial_clone_filter = NULL;
> +
> +		strbuf_addf(&promisor_config, "remote.%s.partialclonefilter", remote->name);
> +		strbuf_addf(&remote_info_buf, "%s (fetch)", remote->url[0]);
> +		if (!git_config_get_string_tmp(promisor_config.buf, &partial_clone_filter))
> +			strbuf_addf(&remote_info_buf, " [%s]", partial_clone_filter);
> +
> +		strbuf_release(&promisor_config);
>  		string_list_append(list, remote->name)->util =
> -				strbuf_detach(&url_buf, NULL);
> +				strbuf_detach(&remote_info_buf, NULL);

It is unfortunate that the "we borrow without copying" variant of
git_config_get_string() is called git_config_get_string_tmp(), which
is an utterly misleading name that might confuse readers into
mistaking it may make a temporary copy for the caller to release.
Perhaps we would want to rename it to git_config_peek_string() or
something, but that is totally outside the topic, of course.

In any case, what I wanted to say is that I just made sure that the
value in the partial_clone_filter variable is not leaked.

Looking good.

> diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
> index 4a3778d04a8..bf8f3644d3c 100755
> --- a/t/t5616-partial-clone.sh
> +++ b/t/t5616-partial-clone.sh
> @@ -49,6 +49,17 @@ test_expect_success 'do partial clone 1' '
>  	test "$(git -C pc1 config --local remote.origin.partialclonefilter)" = "blob:none"
>  '
>  
> +test_expect_success 'filters for promisor remotes is listed by git remote -v' '
> +	git clone --filter=blob:none "file://$(pwd)/srv.bare" pc2 &&
> +	git -C pc2 remote -v >out &&
> +	grep "[blob:none]" out &&
> +
> +	git -C pc2 config remote.origin.partialCloneFilter object:type=commit &&
> +	git -C pc2 remote -v >out &&
> +	grep "[object:type=commit]" out &&
> +	rm -rf pc2
> +'

I doubt that these "grep" do what you think it is doing.  It would
say "I am happy" on any line that has one of these characters listed
inside the [].

Do not clean up with an extra "&& clean up" step at the end of
&&-cascade.  Instead use test_when_finished to make sure that after
any failure in the cascade the clean-up step would still trigger.

	test_expect_success 'title' '
		test_when_finished "rm -fr pc2" &&
		git clone ... &&
		...
		grep "srv.bare (fetch) \[object:type=commit\]" out
	'

or something.

Having tests that show how this new feature works is of course
necessary, but we must have negative tests that ensure that it does
*not* trigger when it should not.  E.g. the new [filter-spec] should
not be given for a remote if the user didn't ask for "-v", or the
remote is not a promisor.

Thanks.