show-ref: make --head always show the HEAD ref

The docs seem to say that doing

	git show-ref --head --tags

would show both the HEAD ref and all the tag refs. However, doing
both --head and either of --tags or --heads would filter out the HEAD
ref.

Also update the documentation to describe the new behavior and add
tests for the show-ref command.

[jc: Doug did proofread the tests, but it was done by me and bugs in
it are mine].

Signed-off-by: Doug Bell <madcityzen@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-show-ref.txt

@@ -21,6 +21,8 @@ commit IDs. Results can be filtered using a pattern and tags can be
 dereferenced into object IDs. Additionally, it can be used to test whether a
 particular ref exists.
 
+By default, shows the tags, heads, and remote refs.
+
 The --exclude-existing form is a filter that does the inverse, it shows the
 refs from stdin that don't exist in the local repository.
 
@@ -32,14 +34,14 @@ OPTIONS
 
 --head::
 
-	Show the HEAD reference.
+	Show the HEAD reference, even if it would normally be filtered out.
 
 --tags::
 --heads::
 
-	Limit to only "refs/heads" and "refs/tags", respectively.  These
-	options are not mutually exclusive; when given both, references stored
-	in "refs/heads" and "refs/tags" are displayed.
+	Limit to "refs/heads" and "refs/tags", respectively.  These options
+	are not mutually exclusive; when given both, references stored in
+	"refs/heads" and "refs/tags" are displayed.
 
 -d::
 --dereference::

builtin/show-ref.c

@@ -31,6 +31,9 @@ static int show_ref(const char *refname, const unsigned char *sha1, int flag, vo
 	const char *hex;
 	unsigned char peeled[20];
 
+	if (show_head && !strcmp(refname, "HEAD"))
+		goto match;
+
 	if (tags_only || heads_only) {
 		int match;
 
@@ -167,9 +170,10 @@ static const struct option show_ref_options[] = {
 	OPT_BOOLEAN(0, "verify", &verify, N_("stricter reference checking, "
 		    "requires exact ref path")),
 	{ OPTION_BOOLEAN, 'h', NULL, &show_head, NULL,
-	  N_("show the HEAD reference"),
+	  N_("show the HEAD reference, even if it would be filtered out"),
 	  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN },
-	OPT_BOOLEAN(0, "head", &show_head, N_("show the HEAD reference")),
+	OPT_BOOLEAN(0, "head", &show_head,
+	  N_("show the HEAD reference, even if it would be filtered out")),
 	OPT_BOOLEAN('d', "dereference", &deref_tags,
 		    N_("dereference tags into object IDs")),
 	{ OPTION_CALLBACK, 's', "hash", &abbrev, N_("n"),

t/t1403-show-ref.sh

@@ -0,0 +1,167 @@
+#!/bin/sh
+
+test_description='show-ref'
+. ./test-lib.sh
+
+test_expect_success setup '
+	test_commit A &&
+	git tag -f -a -m "annotated A" A &&
+	git checkout -b side &&
+	test_commit B &&
+	git tag -f -a -m "annotated B" B &&
+	git checkout master &&
+	test_commit C &&
+	git branch B A^0
+'
+
+test_expect_success 'show-ref' '
+	echo $(git rev-parse refs/tags/A) refs/tags/A >expect &&
+
+	git show-ref A >actual &&
+	test_cmp expect actual &&
+
+	git show-ref tags/A >actual &&
+	test_cmp expect actual &&
+
+	git show-ref refs/tags/A >actual &&
+	test_cmp expect actual &&
+
+	>expect &&
+
+	test_must_fail git show-ref D >actual
+	test_cmp expect actual
+'
+
+test_expect_success 'show-ref -q' '
+	>expect &&
+
+	git show-ref -q A >actual &&
+	test_cmp expect actual &&
+
+	git show-ref -q tags/A >actual &&
+	test_cmp expect actual &&
+
+	git show-ref -q refs/tags/A >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref -q D >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'show-ref --verify' '
+	echo $(git rev-parse refs/tags/A) refs/tags/A >expect &&
+
+	git show-ref --verify refs/tags/A >actual &&
+	test_cmp expect actual &&
+
+	>expect &&
+
+	test_must_fail git show-ref --verify A >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref --verify tags/A >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref --verify D >actual
+	test_cmp expect actual
+'
+
+test_expect_success 'show-ref --verify -q' '
+	>expect &&
+
+	git show-ref --verify -q refs/tags/A >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref --verify -q A >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref --verify -q tags/A >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref --verify -q D >actual
+	test_cmp expect actual
+'
+
+test_expect_success 'show-ref -d' '
+	{
+		echo $(git rev-parse refs/tags/A) refs/tags/A &&
+		echo $(git rev-parse refs/tags/A^0) "refs/tags/A^{}"
+		echo $(git rev-parse refs/tags/C) refs/tags/C
+	} >expect &&
+	git show-ref -d A C >actual &&
+	test_cmp expect actual &&
+
+	git show-ref -d tags/A tags/C >actual &&
+	test_cmp expect actual &&
+
+	git show-ref -d refs/tags/A refs/tags/C >actual &&
+	test_cmp expect actual &&
+
+	echo $(git rev-parse refs/heads/master) refs/heads/master >expect &&
+	git show-ref -d master >actual &&
+	test_cmp expect actual &&
+
+	git show-ref -d heads/master >actual &&
+	test_cmp expect actual &&
+
+	git show-ref -d refs/heads/master >actual &&
+	test_cmp expect actual
+
+	git show-ref -d --verify refs/heads/master >actual &&
+	test_cmp expect actual
+
+	>expect &&
+
+	test_must_fail git show-ref -d --verify master >actual &&
+	test_cmp expect actual &&
+
+	test_must_fail git show-ref -d --verify heads/master >actual &&
+	test_cmp expect actual
+
+'
+
+test_expect_success 'show-ref --heads, --tags, --head, pattern' '
+	for branch in B master side
+	do
+		echo $(git rev-parse refs/heads/$branch) refs/heads/$branch
+	done >expect.heads &&
+	git show-ref --heads >actual &&
+	test_cmp expect.heads actual &&
+
+	for tag in A B C
+	do
+		echo $(git rev-parse refs/tags/$tag) refs/tags/$tag
+	done >expect.tags &&
+	git show-ref --tags >actual &&
+	test_cmp expect.tags actual &&
+
+	cat expect.heads expect.tags >expect &&
+	git show-ref --heads --tags >actual &&
+	test_cmp expect actual &&
+
+	{
+		echo $(git rev-parse HEAD) HEAD &&
+		cat expect.heads expect.tags
+	} >expect &&
+	git show-ref --heads --tags --head >actual &&
+	test_cmp expect actual &&
+
+	{
+		echo $(git rev-parse HEAD) HEAD &&
+		echo $(git rev-parse refs/heads/B) refs/heads/B
+		echo $(git rev-parse refs/tags/B) refs/tags/B
+	} >expect &&
+	git show-ref --head B >actual &&
+	test_cmp expect actual &&
+
+	{
+		echo $(git rev-parse HEAD) HEAD &&
+		echo $(git rev-parse refs/heads/B) refs/heads/B
+		echo $(git rev-parse refs/tags/B) refs/tags/B
+		echo $(git rev-parse refs/tags/B^0) "refs/tags/B^{}"
+	} >expect &&
+	git show-ref --head -d B >actual &&
+	test_cmp expect actual
+'
+
+test_done