Subject: Re: [PATCH v2 5/7] fetch/pull: Don't recurse into a submodule when commits are already present

From: Marc Branchaud <[email-masked]>
Date: Wed, 02 Mar 2011 11:08:17 -0500

As I said earlier, this patch should also tweak the documentation in
fetch-options.txt and config.txt.

In my suggested wording I used the phrase

	... only recurse into a populated submodule when its superproject
	retrieves a commit that updates the submodule's reference.

With this patch, that should now be

	... only recurse into a populated submodule when its superproject
	retrieves a commit that updates the submodule's reference to a
	commit that isn't already in the local submodule clone.

		M.

On 11-03-01 06:03 PM, Jens Lehmann wrote:
> When looking for submodules where new commits have been recorded in the
> superproject ignore those cases where the submodules commits are already
> present locally. This can happen e.g. when the submodule has been rewound
> to an earlier state. Then there is no need to fetch the submodule again
> as the commit recorded in the newly fetched superproject commit has
> already been fetched earlier into the submodule.
> 
> Signed-off-by: Jens Lehmann <[email-masked]>
> ---
>  submodule.c                 |   29 ++++++++++++++++++++++++++++-
>  t/t5526-fetch-submodules.sh |   19 +++++++++++++++++++
>  2 files changed, 47 insertions(+), 1 deletions(-)
> 
> diff --git a/submodule.c b/submodule.c
> index 3be6654..11e0ef5 100644
> --- a/submodule.c
> +++ b/submodule.c
> @@ -263,6 +263,33 @@ void set_config_fetch_recurse_submodules(int value)
>  	config_fetch_recurse_submodules = value;
>  }
> 
> +static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
> +{
> +	int is_present = 0;
> +	if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
> +		/* Even if the submodule is checked out and the commit is
> +		 * present, make sure it is reachable from a ref. */
> +		struct child_process cp;
> +		const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
> +		struct strbuf buf = STRBUF_INIT;
> +
> +		argv[3] = sha1_to_hex(sha1);
> +		memset(&cp, 0, sizeof(cp));
> +		cp.argv = argv;
> +		cp.env = local_repo_env;
> +		cp.git_cmd = 1;
> +		cp.no_stdin = 1;
> +		cp.out = -1;
> +		cp.dir = path;
> +		if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
> +			is_present = 1;
> +
> +		close(cp.out);
> +		strbuf_release(&buf);
> +	}
> +	return is_present;
> +}
> +
>  static void submodule_collect_changed_cb(struct diff_queue_struct *q,
>  					 struct diff_options *options,
>  					 void *data)
> @@ -280,7 +307,7 @@ static void submodule_collect_changed_cb(struct diff_queue_struct *q,
>  			 * being moved around. */
>  			struct string_list_item *path;
>  			path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
> -			if (!path)
> +			if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
>  				string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
>  		} else {
>  			/* Submodule is new or was moved here */
> diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
> index 09701aa..3decfae 100755
> --- a/t/t5526-fetch-submodules.sh
> +++ b/t/t5526-fetch-submodules.sh
> @@ -428,4 +428,23 @@ test_expect_success "'submodule.<sub>.fetchRecurseSubmodules=on-demand' override
>  	test_cmp expect.err.2 actual.err
>  '
> 
> +test_expect_success "don't fetch submodule when newly recorded commits are already present" '
> +	(
> +		cd submodule &&
> +		git checkout -q HEAD^^
> +	) &&
> +	head1=$(git rev-parse --short HEAD) &&
> +	git add submodule &&
> +	git commit -m "submodule rewound" &&
> +	head2=$(git rev-parse --short HEAD) &&
> +	echo "From $pwd/." > expect.err &&
> +	echo "   $head1..$head2  master     -> origin/master" >> expect.err &&
> +	(
> +		cd downstream &&
> +		git fetch >../actual.out 2>../actual.err
> +	) &&
> +	! test -s actual.out &&
> +	test_cmp expect.err actual.err
> +'
> +
>  test_done