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[PATCH 2/2] Correct priority of lightweight tags in git-describe.

From
Shawn O. Pearce <spearce@spearce.org>
Date
Jan 14, 2007, 09:37 UTC
Message-ID
<20070114093744.GB15007@spearce.org>
In-Reply-To
<2a044746b474f7c1840116762e79481b4669900e.1168767397.git.spearce@spearce.org>

We really want to always favor an annotated tag over a lightweight tag when describing a commit. Unfortunately git-describe wasn't doing this as it was favoring the depth attribute of a possible_tag over the priority. Now priority is the highest sort and we only consider a lightweight tag if no annotated tags were identified.

Rather than searching for the minimum tag using a simple loop we now sort them using a stable sort algorithm, this way the possible tags display in order if --debug gets used. The stable sort helps to preseve the inherit topology/date order that we obtain during our search loop.

This fix allows the tests in t6120-describe.sh to pass.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
---
 builtin-describe.c |   30 +++++++++++++++++++-----------
 1 files changed, 19 insertions(+), 11 deletions(-)
diff --git a/builtin-describe.c b/builtin-describe.c
index 421658d..45fea10 100644
--- a/builtin-describe.c
+++ b/builtin-describe.c
@@ -22,6 +22,9 @@ static struct commit_name {
 	int prio; /* annotated tag = 2, tag = 1, head = 0 */
 	char path[FLEX_ARRAY]; /* more */
 } **name_array[256];
+static const char *prio_names[] = {
+	"head", "lightweight", "annotated",
+};
 
 static struct commit_name *match(struct commit *cmit)
 {
@@ -122,6 +125,17 @@ struct possible_tag {
 	unsigned flag_within;
 };
 
+static int compare_pt(const void *_a, const void *_b)
+{
+	struct possible_tag *a = (struct possible_tag *)_a;
+	struct possible_tag *b = (struct possible_tag *)_b;
+	if (a->name->prio != b->name->prio)
+		return b->name->prio - a->name->prio;
+	if (a->depth != b->depth)
+		return a->depth - b->depth;
+	return 0;
+}
+
 static void describe(const char *arg, int last_one)
 {
 	unsigned char sha1[20];
@@ -129,7 +143,7 @@ static void describe(const char *arg, int last_one)
 	struct commit_list *list;
 	static int initialized = 0;
 	struct commit_name *n;
-	struct possible_tag all_matches[MAX_TAGS], *min_match;
+	struct possible_tag all_matches[MAX_TAGS];
 	unsigned int match_cnt = 0, annotated_cnt = 0, cur_match;
 	unsigned long seen_commits = 0;
 
@@ -205,18 +219,12 @@ static void describe(const char *arg, int last_one)
 	if (!match_cnt)
 		die("cannot describe '%s'", sha1_to_hex(cmit->object.sha1));
 
-	min_match = &all_matches[0];
-	for (cur_match = 1; cur_match < match_cnt; cur_match++) {
-		struct possible_tag *t = &all_matches[cur_match];
-		if (t->depth < min_match->depth
-			&& t->name->prio >= min_match->name->prio)
-			min_match = t;
-	}
+	mergesort(all_matches, match_cnt, sizeof(all_matches[0]), compare_pt);
 	if (debug) {
 		for (cur_match = 0; cur_match < match_cnt; cur_match++) {
 			struct possible_tag *t = &all_matches[cur_match];
-			fprintf(stderr, " %c %8lu %s\n",
-				min_match == t ? '*' : ' ',
+			fprintf(stderr, " %-11s %8lu %s\n",
+				prio_names[t->name->prio],
 				t->depth, t->name->path);
 		}
 		fprintf(stderr, "traversed %lu commits\n", seen_commits);
@@ -228,7 +236,7 @@ static void describe(const char *arg, int last_one)
 				sha1_to_hex(gave_up_on->object.sha1));
 		}
 	}
-	printf("%s-g%s\n", min_match->name->path,
+	printf("%s-g%s\n", all_matches[0].name->path,
 		   find_unique_abbrev(cmit->object.sha1, abbrev));
 
 	if (!last_one)
-- 
1.5.0.rc1.g4494
Next: Junio C Hamano
Message 1 of 3 in “Correct priority of lightweight tags in git-describe.”
  1. 2/2 Correct priority of lightweight tags in git-describe.Shawn O. Pearce, Jan 14, 2007
  2. Junio C HamanoJan 14, 2007
  3. Shawn O. PearceJan 14, 2007

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