fetch/pull: Recursively fetch populated submodules

Until now you had to call "git submodule update" (without -N|--no-fetch
option) or something like "git submodule foreach git fetch" to fetch
new commits in populated submodules from their remote.

This could lead to "(commits not present)" messages in the output of
"git diff --submodule" (and in "git gui" and "gitk") after fetching
or pulling new commits in the superproject and is an obstacle for
implementing recursive checkout of submodules.

This patch recursively fetches each populated submodule from the url
configured in the .git/config of the submodule at the end of each
"git fetch" or during "git pull" in the superproject. This new behavior
can be disabled by using the new --no-recursive option.

t7403 had to be changed to use the --no-recursive option for pull.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/fetch-options.txt

@@ -60,6 +60,11 @@ endif::git-pull[]
 	flag lets all tags and their associated objects be
 	downloaded.
 
+--[no-]recursive::
+	By default new commits of all populated submodules will be fetched
+	too. This option can be used to disable/enable recursive fetching of
+	submodules.
+
 -u::
 --update-head-ok::
 	By default 'git fetch' refuses to update the head which

builtin/fetch.c

@@ -12,6 +12,7 @@
 #include "parse-options.h"
 #include "sigchain.h"
 #include "transport.h"
+#include "submodule.h"
 
 static const char * const builtin_fetch_usage[] = {
 	"git fetch [<options>] [<repository> [<refspec>...]]",
@@ -27,7 +28,7 @@ enum {
 	TAGS_SET = 2
 };
 
-static int all, append, dry_run, force, keep, multiple, prune, update_head_ok, verbosity;
+static int all, append, dry_run, force, keep, multiple, prune, recursive = -1, update_head_ok, verbosity;
 static int progress;
 static int tags = TAGS_DEFAULT;
 static const char *depth;
@@ -53,6 +54,8 @@ static struct option builtin_fetch_options[] = {
 		    "do not fetch all tags (--no-tags)", TAGS_UNSET),
 	OPT_BOOLEAN('p', "prune", &prune,
 		    "prune tracking branches no longer on remote"),
+	OPT_BOOLEAN(0, "recursive", &recursive,
+		    "control recursive fetching of submodules"),
 	OPT_BOOLEAN(0, "dry-run", &dry_run,
 		    "dry run"),
 	OPT_BOOLEAN('k', "keep", &keep, "keep downloaded pack"),
@@ -919,6 +922,12 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 		}
 	}
 
+	if (!result && recursive) {
+		gitmodules_config();
+		git_config(submodule_config, NULL);
+		result = fetch_populated_submodules();
+	}
+
 	/* All names were strdup()ed or strndup()ed */
 	list.strdup_strings = 1;
 	string_list_clear(&list, 0);

git-pull.sh

@@ -38,7 +38,7 @@ test -z "$(git ls-files -u)" || die_conflict
 test -f "$GIT_DIR/MERGE_HEAD" && die_merge
 
 strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
-log_arg= verbosity= progress=
+log_arg= verbosity= progress= recursive=
 merge_args=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short="${curr_branch#refs/heads/}"
@@ -105,6 +105,12 @@ do
 	--no-r|--no-re|--no-reb|--no-reba|--no-rebas|--no-rebase)
 		rebase=false
 		;;
+	--recursive)
+		recursive=--recursive
+		;;
+	--no-recursive)
+		recursive=--no-recursive
+		;;
 	--d|--dr|--dry|--dry-|--dry-r|--dry-ru|--dry-run)
 		dry_run=--dry-run
 		;;
@@ -220,7 +226,7 @@ test true = "$rebase" && {
 	done
 }
 orig_head=$(git rev-parse -q --verify HEAD)
-git fetch $verbosity $progress $dry_run --update-head-ok "$@" || exit 1
+git fetch $verbosity $progress $dry_run $recursive --update-head-ok "$@" || exit 1
 test -z "$dry_run" || exit 0
 
 curr_head=$(git rev-parse -q --verify HEAD)

submodule.c

@@ -63,7 +63,7 @@ void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 	}
 }
 
-static int submodule_config(const char *var, const char *value, void *cb)
+int submodule_config(const char *var, const char *value, void *cb)
 {
 	if (!prefixcmp(var, "submodule."))
 		return parse_submodule_config_option(var, value);
@@ -229,6 +229,47 @@ void show_submodule_summary(FILE *f, const char *path,
 	strbuf_release(&sb);
 }
 
+int fetch_populated_submodules()
+{
+	int result = 0;
+	struct child_process cp;
+	const char *argv[] = {
+		"fetch",
+		NULL,
+	};
+	struct string_list_item *name_for_path;
+	const char *work_tree = get_git_work_tree();
+	if (!work_tree)
+		return 0;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.argv = argv;
+	cp.env = local_repo_env;
+	cp.git_cmd = 1;
+	cp.no_stdin = 1;
+	cp.out = -1;
+
+	for_each_string_list_item(name_for_path, &config_name_for_path) {
+		struct strbuf submodule_path = STRBUF_INIT;
+		struct strbuf submodule_git_dir = STRBUF_INIT;
+		const char *git_dir;
+		strbuf_addf(&submodule_path, "%s/%s", work_tree, name_for_path->string);
+		strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
+		git_dir = read_gitfile_gently(submodule_git_dir.buf);
+		if (!git_dir)
+			git_dir = submodule_git_dir.buf;
+		if (is_directory(git_dir)) {
+			printf("Fetching submodule %s\n", name_for_path->string);
+			cp.dir = submodule_path.buf;
+			if (run_command(&cp))
+				result = 1;
+		}
+		strbuf_release(&submodule_path);
+		strbuf_release(&submodule_git_dir);
+	}
+	return result;
+}
+
 unsigned is_submodule_modified(const char *path, int ignore_untracked)
 {
 	ssize_t len;

submodule.h

@@ -5,6 +5,7 @@ struct diff_options;
 
 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 		const char *path);
+int submodule_config(const char *var, const char *value, void *cb);
 void gitmodules_config();
 int parse_submodule_config_option(const char *var, const char *value);
 void handle_ignore_submodules_arg(struct diff_options *diffopt, const char *);
@@ -12,6 +13,7 @@ void show_submodule_summary(FILE *f, const char *path,
 		unsigned char one[20], unsigned char two[20],
 		unsigned dirty_submodule,
 		const char *del, const char *add, const char *reset);
+int fetch_populated_submodules();
 unsigned is_submodule_modified(const char *path, int ignore_untracked);
 int merge_submodule(unsigned char result[20], const char *path, const unsigned char base[20],
 		    const unsigned char a[20], const unsigned char b[20]);

t/t5526-fetch-submodules.sh

@@ -0,0 +1,64 @@
+#!/bin/sh
+# Copyright (c) 2010, Jens Lehmann
+
+test_description='Recursive "git fetch" for submodules'
+
+. ./test-lib.sh
+
+pwd=$(pwd)
+
+add_upstream_commit() {
+	(
+		cd submodule &&
+		head1=$(git rev-parse --short HEAD) &&
+		echo new >> subfile &&
+		test_tick &&
+		git add subfile &&
+		git commit -m new subfile &&
+		head2=$(git rev-parse --short HEAD) &&
+		echo "From $pwd/submodule" > ../expect.err
+		echo "   $head1..$head2  master     -> origin/master" >> ../expect.err
+	)
+}
+
+test_expect_success setup '
+	mkdir submodule &&
+	(
+		cd submodule &&
+		git init &&
+		echo subcontent > subfile &&
+		git add subfile &&
+		git commit -m new subfile
+	) &&
+	git submodule add "$pwd/submodule" submodule &&
+	git commit -am initial &&
+	git clone . downstream &&
+	(
+		cd downstream &&
+		git submodule init &&
+		git submodule update
+	) &&
+	echo "Fetching submodule submodule" > expect.out
+'
+
+test_expect_success "fetch recurses into submodules" '
+	add_upstream_commit &&
+	(
+		cd downstream &&
+		git fetch >../actual.out 2>../actual.err
+	) &&
+	test_cmp expect.out actual.out &&
+	test_cmp expect.err actual.err
+'
+
+test_expect_success "fetch --no-recursive only fetches superproject" '
+	add_upstream_commit &&
+	(
+		cd downstream &&
+		git fetch --no-recursive >../actual.out 2>../actual.err
+	) &&
+	! test -s actual.out &&
+	! test -s actual.err
+'
+
+test_done

t/t7403-submodule-sync.sh

@@ -50,7 +50,7 @@ test_expect_success 'change submodule url' '
 
 test_expect_success '"git submodule sync" should update submodule URLs' '
 	(cd super-clone &&
-	 git pull &&
+	 git pull --no-recursive &&
 	 git submodule sync
 	) &&
 	test -d "$(git config -f super-clone/submodule/.git/config \