git-describe: --tags and --abbrev

With --tags, not just annontated tags, but also any ref under
refs/tags/ are used to name the revision.

The number of digits is configurable with the --abbrev=<n> option.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/describe.c b/describe.c
index ba49d0027092393a6b0b578dafdbfef15f791eaf..ee38f5f5d8791646cd6ca0f1d2570d793afa78a9 100644 (file)
--- a/describe.c
+++ b/describe.c
@@ -5,9 +5,14 @@
 
 #define SEEN (1u << 0)
 
-static const char describe_usage[] = "git-describe [--all] <committish>*";
+static const char describe_usage[] =
+"git-describe [--all] [--tags] [--abbrev=<n>] <committish>*";
 
 static int all = 0;    /* Default to annotated tags only */
+static int tags = 0;   /* But allow any tags if --tags is specified */
+
+#define DEFAULT_ABBREV 8 /* maybe too many */
+static int abbrev = DEFAULT_ABBREV;
 
 static int names = 0, allocs = 0;
 static struct commit_name {
@@ -50,13 +55,19 @@ static int get_name(const char *path, const unsigned char *sha1)
        struct commit *commit = lookup_commit_reference_gently(sha1, 1);
        if (!commit)
                return 0;
+       /* If --all, then any refs are used.
+        * If --tags, then any tags are used.
+        * Otherwise only annotated tags are used.
+        */
        if (!all) {
-               struct object *object;
                if (strncmp(path, "refs/tags/", 10))
                        return 0;
-               object = parse_object(sha1);
-               if (object->type != tag_type)
-                       return 0;
+               if (!tags) {
+                       struct object *object;
+                       object = parse_object(sha1);
+                       if (object->type != tag_type)
+                               return 0;
+               }
        }
        add_to_known_names(all ? path : path + 10, commit);
        return 0;
@@ -96,7 +107,7 @@ static void describe(struct commit *cmit)
                n = match(c);
                if (n) {
                        printf("%s-g%s\n", n->path,
-                              find_unique_abbrev(cmit->object.sha1, 8));
+                              find_unique_abbrev(cmit->object.sha1, abbrev));
                        return;
                }
        }
@@ -115,6 +126,16 @@ int main(int argc, char **argv)
                        all = 1;
                        continue;
                }
+               if (!strcmp(arg, "--tags")) {
+                       tags = 1;
+                       continue;
+               }
+               if (!strncmp(arg, "--abbrev=", 9)) {
+                       abbrev = strtoul(arg + 9, NULL, 10);
+                       if (abbrev < 4 || 40 <= abbrev)
+                               abbrev = DEFAULT_ABBREV;
+                       continue;
+               }
                if (get_sha1(arg, sha1) < 0)
                        usage(describe_usage);
                cmit = lookup_commit_reference(sha1);