for-each-ref: add '--merged' and '--no-merged' options

Add the '--merged' and '--no-merged' options provided by 'ref-filter'.
The '--merged' option lets the user to only list refs merged into the
named commit. The '--no-merged' option lets the user to only list refs
not merged into the named commit.

Add documentation and tests for the same.
Based-on-patch-by: NJeff King <peff@peff.net>
Mentored-by: NChristian Couder <christian.couder@gmail.com>
Mentored-by: NMatthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: NKarthik Nayak <karthik.188@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

Documentation/git-for-each-ref.txt

@@ -10,7 +10,7 @@ SYNOPSIS
 [verse]
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>] [<pattern>...]
-		   [--points-at <object>]
+		   [--points-at <object>] [(--merged | --no-merged) [<object>]]
 
 DESCRIPTION
 -----------
@@ -66,6 +66,14 @@ OPTIONS
 --points-at <object>::
 	Only list refs which points at the given object.
 
+--merged [<object>]::
+	Only list refs whose tips are reachable from the
+	specified commit (HEAD if not specified).
+
+--no-merged [<object>]::
+	Only list refs whose tips are not reachable from the
+	specified commit (HEAD if not specified).
+
 FIELD NAMES
 -----------
 

builtin/for-each-ref.c

@@ -8,6 +8,7 @@
 static char const * const for_each_ref_usage[] = {
 	N_("git for-each-ref [<options>] [<pattern>]"),
 	N_("git for-each-ref [--points-at <object>]"),
+	N_("git for-each-ref [(--merged | --no-merged) [<object>]]"),
 	NULL
 };
 
@@ -38,6 +39,8 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK(0, "points-at", &filter.points_at,
 			     N_("object"), N_("print only refs which points at the given object"),
 			     parse_opt_object_name),
+		OPT_MERGED(&filter, N_("print only refs that are merged")),
+		OPT_NO_MERGED(&filter, N_("print only refs that are not merged")),
 		OPT_END(),
 	};
 

t/t6302-for-each-ref-filter.sh

@@ -43,4 +43,27 @@ test_expect_success 'check signed tags with --points-at' '
 	test_cmp expect actual
 '
 
+test_expect_success 'filtering with --merged' '
+	cat >expect <<-\EOF &&
+	refs/heads/master
+	refs/odd/spot
+	refs/tags/one
+	refs/tags/three
+	refs/tags/two
+	EOF
+	git for-each-ref --format="%(refname)" --merged=master >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'filtering with --no-merged' '
+	cat >expect <<-\EOF &&
+	refs/heads/side
+	refs/tags/double-tag
+	refs/tags/four
+	refs/tags/signed-tag
+	EOF
+	git for-each-ref --format="%(refname)" --no-merged=master >actual &&
+	test_cmp expect actual
+'
+
 test_done