From: Junio C Hamano <gitster@pobox.com>
Date: Sat, 24 Jun 2017 22:29:27 +0000 (-0700)
Subject: Merge branch 'jc/name-rev-lw-tag' into maint
X-Git-Tag: v2.13.2~12
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/e8d9d8b0bdb8c43c8c5e23c3a2fe99a1dcbe8015?ds=inline;hp=-c

Merge branch 'jc/name-rev-lw-tag' into maint

"git describe --contains" penalized light-weight tags so much that
they were almost never considered.  Instead, give them about the
same chance to be considered as an annotated tag that is the same
age as the underlying commit would.

* jc/name-rev-lw-tag:
name-rev: favor describing with tags and use committer date to tiebreak
name-rev: refactor logic to see if a new candidate is a better name
---

e8d9d8b0bdb8c43c8c5e23c3a2fe99a1dcbe8015
diff --combined builtin/name-rev.c
index e7a3fe7ee7,bf7ed015ae..1767af750d
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@@ -13,6 -13,7 +13,7 @@@ typedef struct rev_name 
  	unsigned long taggerdate;
  	int generation;
  	int distance;
+ 	int from_tag;
  } rev_name;
  
  static long cutoff = LONG_MAX;
@@@ -20,15 -21,52 +21,53 @@@
  /* How many generations are maximally preferred over _one_ merge traversal? */
  #define MERGE_TRAVERSAL_WEIGHT 65535
  
+ static int is_better_name(struct rev_name *name,
+ 			  const char *tip_name,
+ 			  unsigned long taggerdate,
+ 			  int generation,
+ 			  int distance,
+ 			  int from_tag)
+ {
+ 	/*
+ 	 * When comparing names based on tags, prefer names
+ 	 * based on the older tag, even if it is farther away.
+ 	 */
+ 	if (from_tag && name->from_tag)
+ 		return (name->taggerdate > taggerdate ||
+ 			(name->taggerdate == taggerdate &&
+ 			 name->distance > distance));
+ 
+ 	/*
+ 	 * We know that at least one of them is a non-tag at this point.
+ 	 * favor a tag over a non-tag.
+ 	 */
+ 	if (name->from_tag != from_tag)
+ 		return from_tag;
+ 
+ 	/*
+ 	 * We are now looking at two non-tags.  Tiebreak to favor
+ 	 * shorter hops.
+ 	 */
+ 	if (name->distance != distance)
+ 		return name->distance > distance;
+ 
+ 	/* ... or tiebreak to favor older date */
+ 	if (name->taggerdate != taggerdate)
+ 		return name->taggerdate > taggerdate;
+ 
+ 	/* keep the current one if we cannot decide */
+ 	return 0;
+ }
+ 
  static void name_rev(struct commit *commit,
  		const char *tip_name, unsigned long taggerdate,
- 		int generation, int distance,
+ 		int generation, int distance, int from_tag,
  		int deref)
  {
  	struct rev_name *name = (struct rev_name *)commit->util;
  	struct commit_list *parents;
  	int parent_number = 1;
 +	char *to_free = NULL;
  
  	parse_commit(commit);
  
@@@ -36,7 -74,7 +75,7 @@@
  		return;
  
  	if (deref) {
 -		tip_name = xstrfmt("%s^0", tip_name);
 +		tip_name = to_free = xstrfmt("%s^0", tip_name);
  
  		if (generation)
  			die("generation: %d, but deref?", generation);
@@@ -46,18 -84,16 +85,18 @@@
  		name = xmalloc(sizeof(rev_name));
  		commit->util = name;
  		goto copy_data;
- 	} else if (name->taggerdate > taggerdate ||
- 			(name->taggerdate == taggerdate &&
- 			 name->distance > distance)) {
+ 	} else if (is_better_name(name, tip_name, taggerdate,
+ 				  generation, distance, from_tag)) {
  copy_data:
  		name->tip_name = tip_name;
  		name->taggerdate = taggerdate;
  		name->generation = generation;
  		name->distance = distance;
+ 		name->from_tag = from_tag;
 -	} else
 +	} else {
 +		free(to_free);
  		return;
 +	}
  
  	for (parents = commit->parents;
  			parents;
@@@ -75,10 -111,12 +114,12 @@@
  						   parent_number);
  
  			name_rev(parents->item, new_name, taggerdate, 0,
- 				distance + MERGE_TRAVERSAL_WEIGHT, 0);
+ 				 distance + MERGE_TRAVERSAL_WEIGHT,
+ 				 from_tag, 0);
  		} else {
  			name_rev(parents->item, tip_name, taggerdate,
- 				generation + 1, distance + 1, 0);
+ 				 generation + 1, distance + 1,
+ 				 from_tag, 0);
  		}
  	}
  }
@@@ -209,9 -247,13 +250,13 @@@ static int name_ref(const char *path, c
  	}
  	if (o && o->type == OBJ_COMMIT) {
  		struct commit *commit = (struct commit *)o;
+ 		int from_tag = starts_with(path, "refs/tags/");
  
+ 		if (taggerdate == ULONG_MAX)
+ 			taggerdate = ((struct commit *)o)->date;
  		path = name_ref_abbrev(path, can_abbreviate_output);
- 		name_rev(commit, xstrdup(path), taggerdate, 0, 0, deref);
+ 		name_rev(commit, xstrdup(path), taggerdate, 0, 0,
+ 			 from_tag, deref);
  	}
  	return 0;
  }
@@@ -241,9 -283,10 +286,9 @@@ static const char *get_exact_ref_match(
  	return NULL;
  }
  
 -/* returns a static buffer */
 -static const char *get_rev_name(const struct object *o)
 +/* may return a constant string or use "buf" as scratch space */
 +static const char *get_rev_name(const struct object *o, struct strbuf *buf)
  {
 -	static char buffer[1024];
  	struct rev_name *n;
  	struct commit *c;
  
@@@ -260,9 -303,10 +305,9 @@@
  		int len = strlen(n->tip_name);
  		if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
  			len -= 2;
 -		snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
 -				n->generation);
 -
 -		return buffer;
 +		strbuf_reset(buf);
 +		strbuf_addf(buf, "%.*s~%d", len, n->tip_name, n->generation);
 +		return buf->buf;
  	}
  }
  
@@@ -272,11 -316,10 +317,11 @@@ static void show_name(const struct obje
  {
  	const char *name;
  	const struct object_id *oid = &obj->oid;
 +	struct strbuf buf = STRBUF_INIT;
  
  	if (!name_only)
  		printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
 -	name = get_rev_name(obj);
 +	name = get_rev_name(obj, &buf);
  	if (name)
  		printf("%s\n", name);
  	else if (allow_undefined)
@@@ -285,7 -328,6 +330,7 @@@
  		printf("%s\n", find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
  	else
  		die("cannot describe '%s'", oid_to_hex(oid));
 +	strbuf_release(&buf);
  }
  
  static char const * const name_rev_usage[] = {
@@@ -297,7 -339,6 +342,7 @@@
  
  static void name_rev_line(char *p, struct name_ref_data *data)
  {
 +	struct strbuf buf = STRBUF_INIT;
  	int forty = 0;
  	char *p_start;
  	for (p_start = p; *p; p++) {
@@@ -318,7 -359,7 +363,7 @@@
  				struct object *o =
  					lookup_object(sha1);
  				if (o)
 -					name = get_rev_name(o);
 +					name = get_rev_name(o, &buf);
  			}
  			*(p+1) = c;
  
@@@ -336,8 -377,6 +381,8 @@@
  	/* flush */
  	if (p_start != p)
  		fwrite(p_start, p - p_start, 1, stdout);
 +
 +	strbuf_release(&buf);
  }
  
  int cmd_name_rev(int argc, const char **argv, const char *prefix)
diff --combined t/t4202-log.sh
index 1c7d6729c6,038911f230..6499cdf6ff
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@@ -4,7 -4,6 +4,7 @@@ test_description='git log
  
  . ./test-lib.sh
  . "$TEST_DIRECTORY/lib-gpg.sh"
 +. "$TEST_DIRECTORY/lib-terminal.sh"
  
  test_expect_success setup '
  
@@@ -399,7 -398,7 +399,7 @@@ cat > expect <<\EO
  | |
  | |     Merge branch 'side'
  | |
- | * commit side
+ | * commit tags/side-2
  | | Author: A U Thor <author@example.com>
  | |
  | |     side-2
@@@ -521,7 -520,7 +521,7 @@@ test_expect_success 'log --graph with m
  '
  
  test_expect_success 'log.decorate configuration' '
 -	git log --oneline >expect.none &&
 +	git log --oneline --no-decorate >expect.none &&
  	git log --oneline --decorate >expect.short &&
  	git log --oneline --decorate=full >expect.full &&
  
@@@ -577,25 -576,6 +577,25 @@@
  
  '
  
 +test_expect_success 'log.decorate config parsing' '
 +	git log --oneline --decorate=full >expect.full &&
 +	git log --oneline --decorate=short >expect.short &&
 +
 +	test_config log.decorate full &&
 +	test_config log.mailmap true &&
 +	git log --oneline >actual &&
 +	test_cmp expect.full actual &&
 +	git log --oneline --decorate=short >actual &&
 +	test_cmp expect.short actual
 +'
 +
 +test_expect_success TTY 'log output on a TTY' '
 +	git log --oneline --decorate >expect.short &&
 +
 +	test_terminal git log --oneline >actual &&
 +	test_cmp expect.short actual
 +'
 +
  test_expect_success 'reflog is expected format' '
  	git log -g --abbrev-commit --pretty=oneline >expect &&
  	git reflog >actual &&