[PATCH] Show submodules as modified when they contain a dirty work tree

@@ -159,7 +159,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 				continue;
 		}

-		if (ce_uptodate(ce) || ce_skip_worktree(ce))
+		if ((ce_uptodate(ce) && !S_ISGITLINK(ce->ce_mode)) || ce_skip_worktree(ce))
 			continue;

 		/* If CE_VALID is set, don't look at workdir for file removal */

@@ -176,6 +176,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			continue;
 		}
 		changed = ce_match_stat(ce, &st, ce_option);
+		if (S_ISGITLINK(ce->ce_mode) && !changed)
+			changed = is_submodule_modified(ce->name);
 		if (!changed) {
 			ce_mark_uptodate(ce);
 			if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))

@@ -4,6 +4,7 @@
 #include "diff.h"
 #include "commit.h"
 #include "revision.h"
+#include "run-command.h"

 int add_submodule_odb(const char *path)
 {

@@ -112,3 +113,51 @@ void show_submodule_summary(FILE *f, const char *path,
 	}
 	strbuf_release(&sb);
 }
+
+int is_submodule_modified(const char *path)
+{
+	int len;
+	struct child_process cp;
+	const char *argv[] = {
+		"status",
+		"--porcelain",
+		NULL,
+	};
+	char *env[3];
+	struct strbuf buf = STRBUF_INIT;
+
+	strbuf_addf(&buf, "%s/.git/", path);
+	if (!is_directory(buf.buf)) {
+		strbuf_release(&buf);
+		/* The submodule is not checked out, so it is not modified */
+		return 0;
+
+	}
+	strbuf_reset(&buf);
+
+	strbuf_addf(&buf, "GIT_WORK_TREE=%s", path);
+	env[0] = strbuf_detach(&buf, NULL);
+	strbuf_addf(&buf, "GIT_DIR=%s/.git", path);
+	env[1] = strbuf_detach(&buf, NULL);
+	env[2] = NULL;
+
+	memset(&cp, 0, sizeof(cp));
+	cp.argv = argv;
+	cp.env = (const char *const *)env;
+	cp.git_cmd = 1;
+	cp.no_stdin = 1;
+	cp.out = -1;
+	if (start_command(&cp))
+		die("Could not run git status --porcelain");
+
+	len = strbuf_read(&buf, cp.out, 1024);
+	close(cp.out);
+
+	if (finish_command(&cp))
+		die("git status --porcelain failed");
+
+	free(env[0]);
+	free(env[1]);
+	strbuf_release(&buf);
+	return len != 0;
+}

@@ -4,5 +4,6 @@
 void show_submodule_summary(FILE *f, const char *path,
 		unsigned char one[20], unsigned char two[20],
 		const char *del, const char *add, const char *reset);
+int is_submodule_modified(const char *path);

 #endif

@@ -10,8 +10,12 @@ test_expect_success 'setup' '
 	: >bar &&
 	git add bar &&
 	git commit -m " Add bar" &&
+	: >foo &&
+	git add foo &&
+	git commit -m " Add foo" &&
 	cd .. &&
-	git add sub &&
+	echo output > .gitignore
+	git add sub .gitignore &&
 	git commit -m "Add submodule sub"
 '

@@ -23,6 +27,31 @@ test_expect_success 'commit --dry-run -a clean' '
 	git commit --dry-run -a |
 	grep "nothing to commit"
 '
+
+echo "changed" > sub/foo
+test_expect_success 'status with modified file in submodule' '
+	git status | grep "modified:   sub"
+'
+test_expect_success 'status with modified file in submodule (porcelain)' '
+	git status --porcelain >output &&
+	diff output - <<-EOF
+ M sub
+EOF
+'
+(cd sub && git checkout foo)
+
+echo "content" > sub/new-file
+test_expect_success 'status with untracked file in submodule' '
+	git status | grep "modified:   sub"
+'
+test_expect_success 'status with untracked file in submodule (porcelain)' '
+	git status --porcelain >output &&
+	diff output - <<-EOF
+ M sub
+EOF
+'
+rm sub/new-file
+
 test_expect_success 'rm submodule contents' '
 	rm -rf sub/* sub/.git
 '