tag: accept multiple patterns for --list

Until now, "git tag -l foo* bar*" would silently ignore the
second argument, showing only refs starting with "foo". It's
not just unfriendly not to take a second pattern; we
actually generated subtly wrong results (from the user's
perspective) because some of the requested tags were
omitted.

This patch allows an arbitrary number of patterns on the
command line; if any of them matches, the ref is shown.

While we're tweaking the documentation, let's also make it
clear that the pattern is fnmatch.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/tag.c b/builtin/tag.c
index b66b34a..55c4721 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -16,7 +16,7 @@
 static const char * const git_tag_usage[] = {
 	"git tag [-a|-s|-u <key-id>] [-f] [-m <msg>|-F <file>] <tagname> [<head>]",
 	"git tag -d <tagname>...",
-	"git tag -l [-n[<num>]] [<pattern>]",
+	"git tag -l [-n[<num>]] [<pattern>...]",
 	"git tag -v <tagname>...",
 	NULL
 };
@@ -24,17 +24,28 @@
 static char signingkey[1000];
 
 struct tag_filter {
-	const char *pattern;
+	const char **patterns;
 	int lines;
 	struct commit_list *with_commit;
 };
 
+static int match_pattern(const char **patterns, const char *ref)
+{
+	/* no pattern means match everything */
+	if (!*patterns)
+		return 1;
+	for (; *patterns; patterns++)
+		if (!fnmatch(*patterns, ref, 0))
+			return 1;
+	return 0;
+}
+
 static int show_reference(const char *refname, const unsigned char *sha1,
 			  int flag, void *cb_data)
 {
 	struct tag_filter *filter = cb_data;
 
-	if (!fnmatch(filter->pattern, refname, 0)) {
+	if (match_pattern(filter->patterns, refname)) {
 		int i;
 		unsigned long size;
 		enum object_type type;
@@ -88,15 +99,12 @@
 	return 0;
 }
 
-static int list_tags(const char *pattern, int lines,
+static int list_tags(const char **patterns, int lines,
 			struct commit_list *with_commit)
 {
 	struct tag_filter filter;
 
-	if (pattern == NULL)
-		pattern = "*";
-
-	filter.pattern = pattern;
+	filter.patterns = patterns;
 	filter.lines = lines;
 	filter.with_commit = with_commit;
 
@@ -414,7 +422,7 @@
 	if (list + delete + verify > 1)
 		usage_with_options(git_tag_usage, options);
 	if (list)
-		return list_tags(argv[0], lines == -1 ? 0 : lines,
+		return list_tags(argv, lines == -1 ? 0 : lines,
 				 with_commit);
 	if (lines != -1)
 		die(_("-n option is only allowed with -l."));