pretty: add tag option to %(describe)

The %(describe) placeholder by default, like `git describe`, only
supports annotated tags. However, some people do use lightweight tags
for releases, and would like to describe those anyway. The command line
tool has an option to support this.

Teach the placeholder to support this as well.

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 33 insertions, 9 deletions

diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index ef6bd420ae..14107ac191 100644
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -220,6 +220,7 @@ The placeholders are:
 			  inconsistent when tags are added or removed at
 			  the same time.
 +
+** 'tags[=<BOOL>]': Also consider lightweight tags.
 ** 'match=<pattern>': Only consider tags matching the given
    `glob(7)` pattern, excluding the "refs/tags/" prefix.
 ** 'exclude=<pattern>': Do not consider tags matching the given
@@ -273,11 +274,6 @@ endif::git-rev-list[]
 			  If any option is provided multiple times the
 			  last occurrence wins.
 +
-The boolean options accept an optional value `[=<BOOL>]`. The values
-`true`, `false`, `on`, `off` etc. are all accepted. See the "boolean"
-sub-section in "EXAMPLES" in linkgit:git-config[1]. If a boolean
-option is given with no value, it's enabled.
-+
 ** 'key=<K>': only show trailers with specified key. Matching is done
    case-insensitively and trailing colon is optional. If option is
    given multiple times trailer lines matching any of the keys are
@@ -313,6 +309,11 @@ insert an empty string unless we are traversing reflog entries (e.g., by
 decoration format if `--decorate` was not already provided on the command
 line.
 
+The boolean options accept an optional value `[=<BOOL>]`. The values
+`true`, `false`, `on`, `off` etc. are all accepted. See the "boolean"
+sub-section in "EXAMPLES" in linkgit:git-config[1]. If a boolean
+option is given with no value, it's enabled.
+
 If you add a `+` (plus sign) after '%' of a placeholder, a line-feed
 is inserted immediately before the expansion if and only if the
 placeholder expands to a non-empty string.
diff --git a/pretty.c b/pretty.c
index 9db2c65538..3a41bedf1a 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1216,28 +1216,43 @@ int format_set_trailers_options(struct process_trailer_options *opts,
 
 static size_t parse_describe_args(const char *start, struct strvec *args)
 {
+	const char *options[] = { "tags" };
 	const char *option_arguments[] = { "match", "exclude" };
 	const char *arg = start;
 
 	for (;;) {
 		const char *matched = NULL;
-		const char *argval;
+		const char *argval = NULL;
 		size_t arglen = 0;
+		int optval = 0;
 		int i;
 
 		for (i = 0; i < ARRAY_SIZE(option_arguments); i++) {
 			if (match_placeholder_arg_value(arg, option_arguments[i], &arg,
 							&argval, &arglen)) {
 				matched = option_arguments[i];
+				if (!arglen)
+					return 0;
 				break;
 			}
 		}
 		if (!matched)
+			for (i = 0; i < ARRAY_SIZE(options); i++) {
+				if (match_placeholder_bool_arg(arg, options[i], &arg,
+								&optval)) {
+					matched = options[i];
+					break;
+				}
+			}
+		if (!matched)
 			break;
 
-		if (!arglen)
-			return 0;
-		strvec_pushf(args, "--%s=%.*s", matched, (int)arglen, argval);
+
+		if (argval) {
+			strvec_pushf(args, "--%s=%.*s", matched, (int)arglen, argval);
+		} else if (optval) {
+			strvec_pushf(args, "--%s", matched);
+		}
 	}
 	return arg - start;
 }
diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index 5865daa8f8..d4acf8882f 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -1002,4 +1002,12 @@ test_expect_success '%(describe:exclude=...) vs git describe --exclude ...' '
 	test_cmp expect actual
 '
 
+test_expect_success '%(describe:tags) vs git describe --tags' '
+	test_when_finished "git tag -d tagname" &&
+	git tag tagname &&
+	git describe --tags >expect &&
+	git log -1 --format="%(describe:tags)" >actual &&
+	test_cmp expect actual
+'
+
 test_done