tag.c: implement '--format' option

KarthikNayak · gitster · commit df0947417acd · 2015-09-17T10:02:49.000-07:00
Implement the '--format' option provided by 'ref-filter'.
This lets the user list tags as per desired format similar
to the implementation in 'git for-each-ref'.

Add tests and documentation for the same.

Mentored-by: Christian Couder &lt;christian.couder@gmail.com&gt;
Mentored-by: Matthieu Moy &lt;matthieu.moy@grenoble-inp.fr&gt;
Signed-off-by: Karthik Nayak &lt;karthik.188@gmail.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
@@ -13,7 +13,8 @@ SYNOPSIS
 	<tagname> [<commit> | <object>]
 'git tag' -d <tagname>...
 'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
-	[--column[=<options>] | --no-column] [--create-reflog] [--sort=<key>] [<pattern>...]
+	[--column[=<options>] | --no-column] [--create-reflog] [--sort=<key>]
+	[--format=<format>] [<pattern>...]
 'git tag' -v <tagname>...
 
 DESCRIPTION
@@ -158,6 +159,11 @@ This option is only applicable when listing tags without annotation lines.
 	The object that the new tag will refer to, usually a commit.
 	Defaults to HEAD.
 
+<format>::
+	A string that interpolates `%(fieldname)` from the object
+	pointed at by a ref being shown.  The format is the same as
+	that of linkgit:git-for-each-ref[1].  When unspecified,
+	defaults to `%(refname:short)`.
 
 CONFIGURATION
 -------------
diff --git a/builtin/tag.c b/builtin/tag.c
@@ -23,30 +23,33 @@ static const char * const git_tag_usage[] = {
 	N_("git tag [-a | -s | -u <key-id>] [-f] [-m <msg> | -F <file>] <tagname> [<head>]"),
 	N_("git tag -d <tagname>..."),
 	N_("git tag -l [-n[<num>]] [--contains <commit>] [--points-at <object>]"
-		"\n\t\t[<pattern>...]"),
+		"\n\t\t[--format=<format>] [<pattern>...]"),
 	N_("git tag -v <tagname>..."),
 	NULL
 };
 
 static unsigned int colopts;
 
-static int list_tags(struct ref_filter *filter, struct ref_sorting *sorting)
+static int list_tags(struct ref_filter *filter, struct ref_sorting *sorting, const char *format)
 {
 	struct ref_array array;
-	char *format, *to_free = NULL;
+	char *to_free = NULL;
 	int i;
 
 	memset(&array, 0, sizeof(array));
 
 	if (filter->lines == -1)
 		filter->lines = 0;
 
-	if (filter->lines) {
-		to_free = xstrfmt("%s %%(contents:lines=%d)",
-				 "%(align:15)%(refname:short)%(end)", filter->lines);
-		format = to_free;
-	} else
-		format = "%(refname:short)";
+	if (!format) {
+		if (filter->lines) {
+			to_free = xstrfmt("%s %%(contents:lines=%d)",
+					  "%(align:15)%(refname:short)%(end)",
+					  filter->lines);
+			format = to_free;
+		} else
+			format = "%(refname:short)";
+	}
 
 	verify_ref_format(format);
 	filter_refs(&array, filter, FILTER_REFS_TAGS);
@@ -330,6 +333,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	struct strbuf err = STRBUF_INIT;
 	struct ref_filter filter;
 	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
+	const char *format = NULL;
 	struct option options[] = {
 		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
 		{ OPTION_INTEGER, 'n', NULL, &filter.lines, N_("n"),
@@ -362,6 +366,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 			OPTION_CALLBACK, 0, "points-at", &filter.points_at, N_("object"),
 			N_("print only tags of the object"), 0, parse_opt_object_name
 		},
+		OPT_STRING(  0 , "format", &format, N_("format"), N_("format to use for the output")),
 		OPT_END()
 	};
 
@@ -402,7 +407,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 			run_column_filter(colopts, &copts);
 		}
 		filter.name_patterns = argv;
-		ret = list_tags(&filter, sorting);
+		ret = list_tags(&filter, sorting, format);
 		if (column_active(colopts))
 			stop_column_filter();
 		return ret;
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
@@ -1519,4 +1519,16 @@ EOF"
 	test_cmp expect actual
 '
 
+test_expect_success '--format should list tags as per format given' '
+	cat >expect <<-\EOF &&
+	refname : refs/tags/foo1.10
+	refname : refs/tags/foo1.3
+	refname : refs/tags/foo1.6
+	refname : refs/tags/foo1.6-rc1
+	refname : refs/tags/foo1.6-rc2
+	EOF
+	git tag -l --format="refname : %(refname)" "foo*" >actual &&
+	test_cmp expect actual
+'
+
 test_done
