Merge branch 'jp/dirty-describe'

* jp/dirty-describe:
  Teach "git describe" --dirty option

Documentation/git-describe.txt

@@ -9,6 +9,7 @@ git-describe - Show the most recent tag that is reachable from a commit
 SYNOPSIS
 --------
 'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] <committish>...
+'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] --dirty[=<mark>]
 
 DESCRIPTION
 -----------
@@ -27,6 +28,11 @@ OPTIONS
 <committish>...::
 	Committish object names to describe.
 
+--dirty[=<mark>]::
+	Describe the working tree.
+	It means describe HEAD and appends <mark> (`-dirty` by
+	default) if the working tree is dirty.
+
 --all::
 	Instead of using only the annotated tags, use any ref
 	found in `.git/refs/`.  This option enables matching

builtin-describe.c

@@ -5,12 +5,14 @@
 #include "builtin.h"
 #include "exec_cmd.h"
 #include "parse-options.h"
+#include "diff.h"
 
 #define SEEN		(1u<<0)
 #define MAX_TAGS	(FLAG_BITS - 1)
 
 static const char * const describe_usage[] = {
 	"git describe [options] <committish>*",
+	"git describe [options] --dirty",
 	NULL
 };
 
@@ -23,6 +25,13 @@ static int max_candidates = 10;
 static int found_names;
 static const char *pattern;
 static int always;
+static const char *dirty;
+
+/* diff-index command arguments to check if working tree is dirty. */
+static const char *diff_index_args[] = {
+	"diff-index", "--quiet", "HEAD", "--", NULL
+};
+
 
 struct commit_name {
 	struct tag *tag;
@@ -199,6 +208,8 @@ static void describe(const char *arg, int last_one)
 		display_name(n);
 		if (longformat)
 			show_suffix(0, n->tag ? n->tag->tagged->sha1 : sha1);
+		if (dirty)
+			printf("%s", dirty);
 		printf("\n");
 		return;
 	}
@@ -256,7 +267,10 @@ static void describe(const char *arg, int last_one)
 	if (!match_cnt) {
 		const unsigned char *sha1 = cmit->object.sha1;
 		if (always) {
-			printf("%s\n", find_unique_abbrev(sha1, abbrev));
+			printf("%s", find_unique_abbrev(sha1, abbrev));
+			if (dirty)
+				printf("%s", dirty);
+			printf("\n");
 			return;
 		}
 		die("cannot describe '%s'", sha1_to_hex(sha1));
@@ -291,6 +305,8 @@ static void describe(const char *arg, int last_one)
 	display_name(all_matches[0].name);
 	if (abbrev)
 		show_suffix(all_matches[0].depth, cmit->object.sha1);
+	if (dirty)
+		printf("%s", dirty);
 	printf("\n");
 
 	if (!last_one)
@@ -315,6 +331,9 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
 			   "only consider tags matching <pattern>"),
 		OPT_BOOLEAN(0, "always",     &always,
 			   "show abbreviated commit object as fallback"),
+		{OPTION_STRING, 0, "dirty",  &dirty, "mark",
+			   "append <mark> on dirty working tree (default: \"-dirty\")",
+		 PARSE_OPT_OPTARG, NULL, (intptr_t) "-dirty"},
 		OPT_END(),
 	};
 
@@ -355,7 +374,11 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
 		die("No names found, cannot describe anything.");
 
 	if (argc == 0) {
+		if (dirty && !cmd_diff_index(ARRAY_SIZE(diff_index_args) - 1, diff_index_args, prefix))
+			dirty = NULL;
 		describe("HEAD", 1);
+	} else if (dirty) {
+		die("--dirty is incompatible with committishes");
 	} else {
 		while (argc-- > 0) {
 			describe(*argv++, argc == 0);

t/t6120-describe.sh

@@ -125,6 +125,20 @@ test_expect_success 'rename tag Q back to A' '
 test_expect_success 'pack tag refs' 'git pack-refs'
 check_describe A-* HEAD
 
+check_describe "A-*[0-9a-f]" --dirty
+
+test_expect_success 'set-up dirty work tree' '
+	echo >>file
+'
+
+check_describe "A-*[0-9a-f]-dirty" --dirty
+
+check_describe "A-*[0-9a-f].mod" --dirty=.mod
+
+test_expect_success 'describe --dirty HEAD' '
+	test_must_fail git describe --dirty HEAD
+'
+
 test_expect_success 'set-up matching pattern tests' '
 	git tag -a -m test-annotated test-annotated &&
 	echo >>file &&