v2, 3 partsgit-submodule summary: --for-status option

git-submodule.sh, t/t7401-submodule-summary.sh

diff --git a/git-submodule.sh b/git-submodule.sh
index 56ec353..d7937a5 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -342,6 +342,7 @@ set_name_rev () {
 #
 cmd_summary() {
 	summary_limit=-1
+	for_status=
 
 	# parse $args after "submodule ... summary".
 	while test $# -ne 0
@@ -350,6 +351,9 @@ cmd_summary() {
 		--cached)
 			cached="$1"
 			;;
+		--for-status)
+			for_status="$1"
+			;;
 		-n|--summary-limit)
 			if summary_limit=$(($2 + 0)) 2>/dev/null && test "$summary_limit" = "$2"
 			then
@@ -398,6 +402,12 @@ cmd_summary() {
 	)
 
 	test -n "$modules" &&
+	if test -n "$for_status"; then
+		echo "# Modified submodules:"
+		echo "#"
+	else
+		true
+	fi &&
 	git diff-index $cached --raw $head -- $modules |
 	grep -e '^:160000' -e '^:[0-7]* 160000' |
 	cut -c2- |
@@ -499,7 +509,12 @@ cmd_summary() {
 			echo
 		fi
 		echo
-	done
+	done |
+	if test -n "$for_status"; then
+		sed -e "s|^|# |" -e 's|^# $|#|'
+	else
+		cat
+	fi
 }
 #
 # List all submodules, prefixed with:
diff --git a/t/t7401-submodule-summary.sh b/t/t7401-submodule-summary.sh
index 0f3c42a..1dbb39d 100755
--- a/t/t7401-submodule-summary.sh
+++ b/t/t7401-submodule-summary.sh
@@ -192,4 +192,17 @@ test_expect_success 'given commit' "
 EOF
 "
 
+test_expect_success '--for-status' "
+    git submodule summary --for-status HEAD^ >actual &&
+    diff actual - <<-EOF
+# Modified submodules:
+#
+# * sm1 $head6...0000000:
+#
+# * sm2 0000000...$head7 (2):
+#   > Add foo9
+#
+EOF
+"
+
 test_done

Documentation/git-status.txt, wt-status.c

diff --git a/Documentation/git-status.txt b/Documentation/git-status.txt
index 3ea269a..32b6660 100644
--- a/Documentation/git-status.txt
+++ b/Documentation/git-status.txt
@@ -52,6 +52,10 @@ If the config variable `status.relativePaths` is set to false, then all
 paths shown are relative to the repository root, not to the current
 directory.
 
+If 'status.submodulesummary' is set to a non zero number, the submodule
+summary will be enabled and a summary of commits for modified submodules
+will be shown (see --summary-limit option of linkgit:git-submodule[1]).
+
 See Also
 --------
 linkgit:gitignore[5]
diff --git a/wt-status.c b/wt-status.c
index b3fd57b..369c519 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -8,9 +8,11 @@
 #include "revision.h"
 #include "diffcore.h"
 #include "quote.h"
+#include "run-command.h"
 
 int wt_status_relative_paths = 1;
 int wt_status_use_color = -1;
+int wt_status_submodule_summary = 0;
 static char wt_status_colors[][COLOR_MAXLEN] = {
 	"",         /* WT_STATUS_HEADER: normal */
 	"\033[32m", /* WT_STATUS_UPDATED: green */
@@ -219,6 +221,38 @@ static void wt_status_print_changed(struct wt_status *s)
 	rev.diffopt.format_callback_data = s;
 	run_diff_files(&rev, 0);
 }
+static void wt_status_print_submodule_summary(struct wt_status *s)
+{
+	struct child_process sm_summary;
+	char summary_limit[64];
+	char index[PATH_MAX];
+	const char *env[] = { index, NULL };
+	const char *argv[] = {
+		"submodule",
+		"summary",
+		"--cached",
+		"--for-status",
+		"--summary-limit",
+		summary_limit,
+		s->amend ? "HEAD^" : "HEAD",
+		NULL
+	};
+
+	if (!wt_status_submodule_summary)
+		return;
+
+	sprintf(summary_limit, "%d", wt_status_submodule_summary);
+	snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", s->index_file);
+
+	memset(&sm_summary, 0, sizeof(sm_summary));
+	sm_summary.argv = argv;
+	sm_summary.env = env;
+	sm_summary.git_cmd = 1;
+	sm_summary.no_stdin = 1;
+	fflush(s->fp);
+	sm_summary.out = dup(fileno(s->fp));    /* run_command closes it */
+	run_command(&sm_summary);
+}
 
 static void wt_status_print_untracked(struct wt_status *s)
 {
@@ -308,6 +342,7 @@ void wt_status_print(struct wt_status *s)
 	}
 
 	wt_status_print_changed(s);
+	wt_status_print_submodule_summary(s);
 	wt_status_print_untracked(s);
 
 	if (s->verbose && !s->is_initial)
@@ -330,6 +365,10 @@ void wt_status_print(struct wt_status *s)
 
 int git_status_config(const char *k, const char *v)
 {
+	if (!strcmp(k, "status.submodulesummary")) {
+		wt_status_submodule_summary = atoi(v);
+		return 0;
+	}
 	if (!strcmp(k, "status.color") || !strcmp(k, "color.status")) {
 		wt_status_use_color = git_config_colorbool(k, v, -1);
 		return 0;

diff --git a/t/t7502-status.sh b/t/t7502-status.sh
index cd08516..33882c9 100755
--- a/t/t7502-status.sh
+++ b/t/t7502-status.sh
@@ -149,4 +149,138 @@ test_expect_success 'status of partial commit excluding new file in index' '
 	test_cmp expect output
 '
 
+test_expect_success "setup status submodule summary" '
+	test_create_repo sm &&
+	cd sm &&
+	: >foo &&
+	git add foo &&
+	git commit -m "Add foo" &&
+	cd .. &&
+	git add sm
+'
+
+cat > expect <<EOF
+# On branch master
+# Changes to be committed:
+#   (use "git reset HEAD <file>..." to unstage)
+#
+#	new file:   dir2/added
+#	new file:   sm
+#
+# Changed but not updated:
+#   (use "git add <file>..." to update what will be committed)
+#
+#	modified:   dir1/modified
+#
+# Untracked files:
+#   (use "git add <file>..." to include in what will be committed)
+#
+#	dir1/untracked
+#	dir2/modified
+#	dir2/untracked
+#	expect
+#	output
+#	untracked
+EOF
+test_expect_success "status submodule summary is disabled by default" '
+	git status > output &&
+	git diff expect output
+'
+
+head=$(cd sm && git rev-parse --short=7 --verify HEAD)
+
+cat > expect <<EOF
+# On branch master
+# Changes to be committed:
+#   (use "git reset HEAD <file>..." to unstage)
+#
+#	new file:   dir2/added
+#	new file:   sm
+#
+# Changed but not updated:
+#   (use "git add <file>..." to update what will be committed)
+#
+#	modified:   dir1/modified
+#
+# Modified submodules:
+#
+# * sm 0000000...$head (1):
+#   > Add foo
+#
+# Untracked files:
+#   (use "git add <file>..." to include in what will be committed)
+#
+#	dir1/untracked
+#	dir2/modified
+#	dir2/untracked
+#	expect
+#	output
+#	untracked
+EOF
+test_expect_success "status submodule summary" '
+	git config status.submodulesummary 10 &&
+	git status > output &&
+	git diff expect output
+'
+
+
+cat > expect <<EOF
+# On branch master
+# Changed but not updated:
+#   (use "git add <file>..." to update what will be committed)
+#
+#	modified:   dir1/modified
+#
+# Untracked files:
+#   (use "git add <file>..." to include in what will be committed)
+#
+#	dir1/untracked
+#	dir2/modified
+#	dir2/untracked
+#	expect
+#	output
+#	untracked
+no changes added to commit (use "git add" and/or "git commit -a")
+EOF
+test_expect_success "status submodule summary (clean submodule)" '
+	git commit -m "commit submodule" &&
+	git config status.submodulesummary 10 &&
+	! git status > output &&
+	git diff expect output
+'
+
+cat > expect <<EOF
+# On branch master
+# Changes to be committed:
+#   (use "git reset HEAD^1 <file>..." to unstage)
+#
+#	new file:   dir2/added
+#	new file:   sm
+#
+# Changed but not updated:
+#   (use "git add <file>..." to update what will be committed)
+#
+#	modified:   dir1/modified
+#
+# Modified submodules:
+#
+# * sm 0000000...$head (1):
+#   > Add foo
+#
+# Untracked files:
+#   (use "git add <file>..." to include in what will be committed)
+#
+#	dir1/untracked
+#	dir2/modified
+#	dir2/untracked
+#	expect
+#	output
+#	untracked
+EOF
+test_expect_success "status submodule summary (--amend)" '
+	git config status.submodulesummary 10 &&
+	git status --amend > output &&
+	git diff expect output
+'
+
 test_done

config.c, wt-status.c

diff --git a/config.c b/config.c
index 0624494..e614456 100644
--- a/config.c
+++ b/config.c
@@ -316,6 +316,21 @@ int git_config_bool(const char *name, const char *value)
 	return git_config_int(name, value) != 0;
 }

+int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
+{
+	*is_bool = 1;
+	if (!value)
+		return 1;
+	if (!*value)
+		return 0;
+	if (!strcasecmp(value, "true") || !strcasecmp(value, "yes"))
+		return 1;
+	if (!strcasecmp(value, "false") || !strcasecmp(value, "no"))
+		return 0;
+	*is_bool = 0;
+	return git_config_int(name, value);
+}
+
 int git_config_string(const char **dest, const char *var, const char *value)
 {
 	if (!value)
diff --git a/wt-status.c b/wt-status.c
index 22385f5..3baa128 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -366,7 +366,10 @@ void wt_status_print(struct wt_status *s)
 int git_status_config(const char *k, const char *v)
 {
 	if (!strcmp(k, "status.submodulesummary")) {
-		wt_status_submodule_summary = atoi(v);
+		int is_bool;
+		wt_status_submodule_summary = git_config_bool_or_int(k, v, &is_bool);
+		if (is_bool && wt_status_submodule_summary)
+			wt_status_submodule_summary = -1;
 		return 0;
 	}
 	if (!strcmp(k, "status.color") || !strcmp(k, "color.status")) {