for-each-ref: add '--contains' option

Add the '--contains' option provided by 'ref-filter'. The '--contains'
option lists only refs which contain the mentioned commit (HEAD if no
commit is explicitly given).

Add documentation and tests for the same.

Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-for-each-ref.txt

@@ -11,6 +11,7 @@ SYNOPSIS
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>] [<pattern>...]
 		   [--points-at <object>] [(--merged | --no-merged) [<object>]]
+		   [--contains [<object>]]
 
 DESCRIPTION
 -----------
@@ -74,6 +75,10 @@ OPTIONS
 	Only list refs whose tips are not reachable from the
 	specified commit (HEAD if not specified).
 
+--contains [<object>]::
+	Only list tags which contain the specified commit (HEAD if not
+	specified).
+
 FIELD NAMES
 -----------
 

builtin/for-each-ref.c

@@ -9,6 +9,7 @@ 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>]]"),
+	N_("git for-each-ref [--contains [<object>]]"),
 	NULL
 };
 
@@ -41,6 +42,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 			     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_CONTAINS(&filter.with_commit, N_("print only refs which contain the commit")),
 		OPT_END(),
 	};
 

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

@@ -66,4 +66,19 @@ test_expect_success 'filtering with --no-merged' '
 	test_cmp expect actual
 '
 
+test_expect_success 'filtering with --contains' '
+	cat >expect <<-\EOF &&
+	refs/heads/master
+	refs/heads/side
+	refs/odd/spot
+	refs/tags/double-tag
+	refs/tags/four
+	refs/tags/signed-tag
+	refs/tags/three
+	refs/tags/two
+	EOF
+	git for-each-ref --format="%(refname)" --contains=two >actual &&
+	test_cmp expect actual
+'
+
 test_done