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[PATCH 4/4] tag: "git tag" refuses to use HEAD as a tagname

From
Junio C Hamano <gitster@pobox.com>
Date
Dec 2, 2024, 07:07 UTC
Message-ID
<20241202070714.3028549-5-gitster@pobox.com>
In-Reply-To
<20241202070714.3028549-1-gitster@pobox.com>

Even though the plumbing level allows you to create refs/tags/HEAD and refs/heads/HEAD, doing so makes it confusing within the context of the UI Git Porcelain commands provides. Just like we prevent a branch from getting called "HEAD" at the Porcelain layer (i.e. "git branch" command), teach "git tag" to refuse to create a tag "HEAD".

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 refs.c         | 2 +-
 t/t7004-tag.sh | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/refs.c b/refs.c
index a24bfe3845..01ef2a3093 100644
--- a/refs.c
+++ b/refs.c
@@ -735,7 +735,7 @@ int check_branch_ref(struct strbuf *sb, const char *name)
 
 int check_tag_ref(struct strbuf *sb, const char *name)
 {
-	if (name[0] == '-')
+	if (name[0] == '-' || !strcmp(name, "HEAD"))
 		return -1;
 
 	strbuf_reset(sb);
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index b1316e62f4..2082ce63f7 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -91,6 +91,12 @@ test_expect_success 'creating a tag using default HEAD should succeed' '
 	test_must_fail git reflog exists refs/tags/mytag
 '
 
+test_expect_success 'HEAD is forbidden as a tagname' '
+	test_when_finished "git tag -d HEAD || :" &&
+	test_must_fail git tag HEAD &&
+	test_must_fail git tag -a -m "useless" HEAD
+'
+
 test_expect_success 'creating a tag with --create-reflog should create reflog' '
 	git log -1 \
 		--format="format:tag: tagging %h (%s, %cd)%n" \
-- 
2.47.1-514-g9b43e7ecc4
Previous: Jeff KingNext: Patrick Steinhardt
Message 14 of 22 in “forbid HEAD as a tagname”
  1. 0/4 forbid HEAD as a tagnameJunio C Hamano, Dec 2, 2024
  2. 1/4 refs: move ref name helpers aroundJunio C Hamano, Dec 2, 2024
  3. Jeff KingDec 2, 2024
  4. Junio C HamanoDec 3, 2024
  5. 2/4 refs: drop strbuf_ prefix from helpersJunio C Hamano, Dec 2, 2024
  6. Jeff KingDec 2, 2024
  7. 3/4 t5604: do not expect that HEAD is a valid tagnameJunio C Hamano, Dec 2, 2024
  8. Kristoffer HaugsbakkDec 2, 2024
  9. Jeff KingDec 2, 2024
  10. Kristoffer HaugsbakkDec 2, 2024
  11. Junio C HamanoDec 3, 2024
  12. Jeff KingDec 5, 2024
  13. Jeff KingDec 2, 2024
  14. 4/4 tag: "git tag" refuses to use HEAD as a tagnameJunio C Hamano, Dec 2, 2024
  15. Patrick SteinhardtDec 2, 2024
  16. shejialuoDec 2, 2024
  17. Junio C HamanoDec 3, 2024
  18. Jeff KingDec 5, 2024
  19. Jeff KingDec 5, 2024
  20. Rubén JustoDec 2, 2024
  21. Junio C HamanoDec 3, 2024
  22. Jeff KingDec 2, 2024

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