git diff --submodule: Show detailed dirty status of submodules

When encountering a dirty submodule while doing "git diff --submodule"
print an extra line for new untracked content and another for modified
but already tracked content. And if the HEAD of the submodule is equal
to the ref diffed against in the superproject, drop the output which
would just show the same SHA1s and no commit message headlines.

To achieve that, the dirty_submodule bitfield is expanded to two bits.
The output of "git status" inside the submodule is parsed to set the
according bits.

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

1 files changed, 35 insertions, 5 deletions

diff --git a/submodule.c b/submodule.c
index 5d286e409e..714ca976b8 100644
--- a/submodule.c
+++ b/submodule.c
@@ -5,6 +5,7 @@
 #include "commit.h"
 #include "revision.h"
 #include "run-command.h"
+#include "diffcore.h"
 
 static int add_submodule_odb(const char *path)
 {
@@ -85,13 +86,21 @@ void show_submodule_summary(FILE *f, const char *path,
 			message = "(revision walker failed)";
 	}
 
+	if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
+		fprintf(f, "Submodule %s contains untracked content\n", path);
+	if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
+		fprintf(f, "Submodule %s contains modified content\n", path);
+
+	if (!hashcmp(one, two)) {
+		strbuf_release(&sb);
+		return;
+	}
+
 	strbuf_addf(&sb, "Submodule %s %s..", path,
 			find_unique_abbrev(one, DEFAULT_ABBREV));
 	if (!fast_backward && !fast_forward)
 		strbuf_addch(&sb, '.');
 	strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
-	if (dirty_submodule)
-		strbuf_add(&sb, "-dirty", 6);
 	if (message)
 		strbuf_addf(&sb, " %s\n", message);
 	else
@@ -121,9 +130,10 @@ void show_submodule_summary(FILE *f, const char *path,
 	strbuf_release(&sb);
 }
 
-int is_submodule_modified(const char *path)
+unsigned is_submodule_modified(const char *path)
 {
-	int len, i;
+	int i;
+	ssize_t len;
 	struct child_process cp;
 	const char *argv[] = {
 		"status",
@@ -132,6 +142,8 @@ int is_submodule_modified(const char *path)
 	};
 	const char *env[LOCAL_REPO_ENV_SIZE + 3];
 	struct strbuf buf = STRBUF_INIT;
+	unsigned dirty_submodule = 0;
+	const char *line, *next_line;
 
 	for (i = 0; i < LOCAL_REPO_ENV_SIZE; i++)
 		env[i] = local_repo_env[i];
@@ -161,6 +173,24 @@ int is_submodule_modified(const char *path)
 		die("Could not run git status --porcelain");
 
 	len = strbuf_read(&buf, cp.out, 1024);
+	line = buf.buf;
+	while (len > 2) {
+		if ((line[0] == '?') && (line[1] == '?')) {
+			dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
+			if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
+				break;
+		} else {
+			dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
+			if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
+				break;
+		}
+		next_line = strchr(line, '\n');
+		if (!next_line)
+			break;
+		next_line++;
+		len -= (next_line - line);
+		line = next_line;
+	}
 	close(cp.out);
 
 	if (finish_command(&cp))
@@ -169,5 +199,5 @@ int is_submodule_modified(const char *path)
 	for (i = LOCAL_REPO_ENV_SIZE; env[i]; i++)
 		free((char *)env[i]);
 	strbuf_release(&buf);
-	return len != 0;
+	return dirty_submodule;
 }