1 files changed, 234 insertions, 16 deletions

diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index c81a7fef26..2c4d435da1 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -27,6 +27,8 @@ int fmt_merge_msg_config(const char *key, const char *value, void *cb)
 			merge_log_config = DEFAULT_MERGE_LOG_LEN;
 	} else if (!strcmp(key, "merge.branchdesc")) {
 		use_branch_desc = git_config_bool(key, value);
+	} else {
+		return git_default_config(key, value, cb);
 	}
 	return 0;
 }
@@ -53,7 +55,48 @@ static void init_src_data(struct src_data *data)
 static struct string_list srcs = STRING_LIST_INIT_DUP;
 static struct string_list origins = STRING_LIST_INIT_DUP;
 
-static int handle_line(char *line)
+struct merge_parents {
+	int alloc, nr;
+	struct merge_parent {
+		unsigned char given[20];
+		unsigned char commit[20];
+		unsigned char used;
+	} *item;
+};
+
+/*
+ * I know, I know, this is inefficient, but you won't be pulling and merging
+ * hundreds of heads at a time anyway.
+ */
+static struct merge_parent *find_merge_parent(struct merge_parents *table,
+					      unsigned char *given,
+					      unsigned char *commit)
+{
+	int i;
+	for (i = 0; i < table->nr; i++) {
+		if (given && hashcmp(table->item[i].given, given))
+			continue;
+		if (commit && hashcmp(table->item[i].commit, commit))
+			continue;
+		return &table->item[i];
+	}
+	return NULL;
+}
+
+static void add_merge_parent(struct merge_parents *table,
+			     unsigned char *given,
+			     unsigned char *commit)
+{
+	if (table->nr && find_merge_parent(table, given, commit))
+		return;
+	ALLOC_GROW(table->item, table->nr + 1, table->alloc);
+	hashcpy(table->item[table->nr].given, given);
+	hashcpy(table->item[table->nr].commit, commit);
+	table->item[table->nr].used = 0;
+	table->nr++;
+}
+
+static int handle_line(char *line, struct merge_parents *merge_parents)
 {
 	int i, len = strlen(line);
 	struct origin_data *origin_data;
@@ -61,6 +104,7 @@ static int handle_line(char *line)
 	struct src_data *src_data;
 	struct string_list_item *item;
 	int pulling_head = 0;
+	unsigned char sha1[20];
 
 	if (len < 43 || line[40] != '\t')
 		return 1;
@@ -71,14 +115,15 @@ static int handle_line(char *line)
 	if (line[41] != '\t')
 		return 2;
 
-	line[40] = 0;
-	origin_data = xcalloc(1, sizeof(struct origin_data));
-	i = get_sha1(line, origin_data->sha1);
-	line[40] = '\t';
-	if (i) {
-		free(origin_data);
+	i = get_sha1_hex(line, sha1);
+	if (i)
 		return 3;
-	}
+
+	if (!find_merge_parent(merge_parents, sha1, NULL))
+		return 0; /* subsumed by other parents */
+
+	origin_data = xcalloc(1, sizeof(struct origin_data));
+	hashcpy(origin_data->sha1, sha1);
 
 	if (line[len - 1] == '\n')
 		line[len - 1] = 0;
@@ -180,6 +225,101 @@ static void add_branch_desc(struct strbuf *out, const char *name)
 	strbuf_release(&desc);
 }
 
+#define util_as_integral(elem) ((intptr_t)((elem)->util))
+
+static void record_person(int which, struct string_list *people,
+			  struct commit *commit)
+{
+	char *name_buf, *name, *name_end;
+	struct string_list_item *elem;
+	const char *field = (which == 'a') ? "\nauthor " : "\ncommitter ";
+
+	name = strstr(commit->buffer, field);
+	if (!name)
+		return;
+	name += strlen(field);
+	name_end = strchrnul(name, '<');
+	if (*name_end)
+		name_end--;
+	while (isspace(*name_end) && name <= name_end)
+		name_end--;
+	if (name_end < name)
+		return;
+	name_buf = xmemdupz(name, name_end - name + 1);
+
+	elem = string_list_lookup(people, name_buf);
+	if (!elem) {
+		elem = string_list_insert(people, name_buf);
+		elem->util = (void *)0;
+	}
+	elem->util = (void*)(util_as_integral(elem) + 1);
+	free(name_buf);
+}
+
+static int cmp_string_list_util_as_integral(const void *a_, const void *b_)
+{
+	const struct string_list_item *a = a_, *b = b_;
+	return util_as_integral(b) - util_as_integral(a);
+}
+
+static void add_people_count(struct strbuf *out, struct string_list *people)
+{
+	if (people->nr == 1)
+		strbuf_addf(out, "%s", people->items[0].string);
+	else if (people->nr == 2)
+		strbuf_addf(out, "%s (%d) and %s (%d)",
+			    people->items[0].string,
+			    (int)util_as_integral(&people->items[0]),
+			    people->items[1].string,
+			    (int)util_as_integral(&people->items[1]));
+	else if (people->nr)
+		strbuf_addf(out, "%s (%d) and others",
+			    people->items[0].string,
+			    (int)util_as_integral(&people->items[0]));
+}
+
+static void credit_people(struct strbuf *out,
+			  struct string_list *them,
+			  int kind)
+{
+	const char *label;
+	const char *me;
+
+	if (kind == 'a') {
+		label = "\n# By ";
+		me = git_author_info(IDENT_NO_DATE);
+	} else {
+		label = "\n# Via ";
+		me = git_committer_info(IDENT_NO_DATE);
+	}
+
+	if (!them->nr ||
+	    (them->nr == 1 &&
+	     me &&
+	     (me = skip_prefix(me, them->items->string)) != NULL &&
+	     skip_prefix(me, " <")))
+		return;
+	strbuf_addstr(out, label);
+	add_people_count(out, them);
+}
+
+static void add_people_info(struct strbuf *out,
+			    struct string_list *authors,
+			    struct string_list *committers)
+{
+	if (authors->nr)
+		qsort(authors->items,
+		      authors->nr, sizeof(authors->items[0]),
+		      cmp_string_list_util_as_integral);
+	if (committers->nr)
+		qsort(committers->items,
+		      committers->nr, sizeof(committers->items[0]),
+		      cmp_string_list_util_as_integral);
+
+	credit_people(out, authors, 'a');
+	credit_people(out, committers, 'c');
+}
+
 static void shortlog(const char *name,
 		     struct origin_data *origin_data,
 		     struct commit *head,
@@ -190,6 +330,8 @@ static void shortlog(const char *name,
 	struct commit *commit;
 	struct object *branch;
 	struct string_list subjects = STRING_LIST_INIT_DUP;
+	struct string_list authors = STRING_LIST_INIT_DUP;
+	struct string_list committers = STRING_LIST_INIT_DUP;
 	int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 	struct strbuf sb = STRBUF_INIT;
 	const unsigned char *sha1 = origin_data->sha1;
@@ -199,7 +341,6 @@ static void shortlog(const char *name,
 		return;
 
 	setup_revisions(0, NULL, rev, NULL);
-	rev->ignore_merges = 1;
 	add_pending_object(rev, branch, name);
 	add_pending_object(rev, &head->object, "^HEAD");
 	head->object.flags |= UNINTERESTING;
@@ -208,10 +349,15 @@ static void shortlog(const char *name,
 	while ((commit = get_revision(rev)) != NULL) {
 		struct pretty_print_context ctx = {0};
 
-		/* ignore merges */
-		if (commit->parents && commit->parents->next)
+		if (commit->parents && commit->parents->next) {
+			/* do not list a merge but count committer */
+			record_person('c', &committers, commit);
 			continue;
-
+		}
+		if (!count)
+			/* the 'tip' committer */
+			record_person('c', &committers, commit);
+		record_person('a', &authors, commit);
 		count++;
 		if (subjects.nr > limit)
 			continue;
@@ -226,6 +372,7 @@ static void shortlog(const char *name,
 			string_list_append(&subjects, strbuf_detach(&sb, NULL));
 	}
 
+	add_people_info(out, &authors, &committers);
 	if (count > limit)
 		strbuf_addf(out, "\n* %s: (%d commits)\n", name, count);
 	else
@@ -246,6 +393,8 @@ static void shortlog(const char *name,
 	rev->commits = NULL;
 	rev->pending.nr = 0;
 
+	string_list_clear(&authors, 0);
+	string_list_clear(&committers, 0);
 	string_list_clear(&subjects, 0);
 }
 
@@ -313,7 +462,10 @@ static void fmt_tag_signature(struct strbuf *tagbuf,
 		strbuf_add(tagbuf, tag_body, buf + len - tag_body);
 	}
 	strbuf_complete_line(tagbuf);
-	strbuf_add_lines(tagbuf, "# ", sig->buf, sig->len);
+	if (sig->len) {
+		strbuf_addch(tagbuf, '\n');
+		strbuf_add_lines(tagbuf, "# ", sig->buf, sig->len);
+	}
 }
 
 static void fmt_merge_msg_sigs(struct strbuf *out)
@@ -366,6 +518,67 @@ static void fmt_merge_msg_sigs(struct strbuf *out)
 	strbuf_release(&tagbuf);
 }
 
+static void find_merge_parents(struct merge_parents *result,
+			       struct strbuf *in, unsigned char *head)
+{
+	struct commit_list *parents, *next;
+	struct commit *head_commit;
+	int pos = 0, i, j;
+
+	parents = NULL;
+	while (pos < in->len) {
+		int len;
+		char *p = in->buf + pos;
+		char *newline = strchr(p, '\n');
+		unsigned char sha1[20];
+		struct commit *parent;
+		struct object *obj;
+
+		len = newline ? newline - p : strlen(p);
+		pos += len + !!newline;
+
+		if (len < 43 ||
+		    get_sha1_hex(p, sha1) ||
+		    p[40] != '\t' ||
+		    p[41] != '\t')
+			continue; /* skip not-for-merge */
+		/*
+		 * Do not use get_merge_parent() here; we do not have
+		 * "name" here and we do not want to contaminate its
+		 * util field yet.
+		 */
+		obj = parse_object(sha1);
+		parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
+		if (!parent)
+			continue;
+		commit_list_insert(parent, &parents);
+		add_merge_parent(result, obj->sha1, parent->object.sha1);
+	}
+	head_commit = lookup_commit(head);
+	if (head_commit)
+		commit_list_insert(head_commit, &parents);
+	parents = reduce_heads(parents);
+
+	while (parents) {
+		for (i = 0; i < result->nr; i++)
+			if (!hashcmp(result->item[i].commit,
+				     parents->item->object.sha1))
+				result->item[i].used = 1;
+		next = parents->next;
+		free(parents);
+		parents = next;
+	}
+
+	for (i = j = 0; i < result->nr; i++) {
+		if (result->item[i].used) {
+			if (i != j)
+				result->item[j] = result->item[i];
+			j++;
+		}
+	}
+	result->nr = j;
+}
+
 int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 		  struct fmt_merge_msg_opts *opts)
 {
@@ -373,6 +586,9 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 	unsigned char head_sha1[20];
 	const char *current_branch;
 	void *current_branch_to_free;
+	struct merge_parents merge_parents;
+
+	memset(&merge_parents, 0, sizeof(merge_parents));
 
 	/* get current branch */
 	current_branch = current_branch_to_free =
@@ -382,6 +598,8 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 	if (!prefixcmp(current_branch, "refs/heads/"))
 		current_branch += 11;
 
+	find_merge_parents(&merge_parents, in, head_sha1);
+
 	/* get a line */
 	while (pos < in->len) {
 		int len;
@@ -392,7 +610,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 		pos += len + !!newline;
 		i++;
 		p[len] = 0;
-		if (handle_line(p))
+		if (handle_line(p, &merge_parents))
 			die ("Error in line %d: %.*s", i, len, p);
 	}
 
@@ -412,8 +630,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 		rev.ignore_merges = 1;
 		rev.limited = 1;
 
-		if (suffixcmp(out->buf, "\n"))
-			strbuf_addch(out, '\n');
+		strbuf_complete_line(out);
 
 		for (i = 0; i < origins.nr; i++)
 			shortlog(origins.items[i].string,
@@ -423,6 +640,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
 	strbuf_complete_line(out);
 	free(current_branch_to_free);
+	free(merge_parents.item);
 	return 0;
 }