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[PATCH v6 19/32] refs: don't dereference on rename

From
David Turner <dturner@twopensource.com>
Date
Feb 24, 2016, 22:58 UTC
Message-ID
<1456354744-8022-20-git-send-email-dturner@twopensource.com>
In-Reply-To
<1456354744-8022-1-git-send-email-dturner@twopensource.com>

When renaming refs, don't dereference either the origin or the destination before renaming.

The origin does not need to be dereferenced because it is presently forbidden to rename symbolic refs.

Not dereferencing the destination fixes a bug where renaming on top of a broken symref would use the pointed-to ref name for the moved reflog.

Add a test for the reflog bug.
Signed-off-by: David Turner <dturner@twopensource.com>
---
 refs/files-backend.c | 15 +++++++++------
 t/t3200-branch.sh    |  9 +++++++++
 2 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 8dc80e2..7a3c9df 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2372,7 +2372,7 @@ static int files_rename_ref(const char *oldrefname, const char *newrefname,
 			    const char *logmsg)
 {
 	unsigned char sha1[20], orig_sha1[20];
-	int flag = 0, logmoved = 0;
+	int flag = 0, logmoved = 0, resolve_flags;
 	struct ref_lock *lock;
 	struct stat loginfo;
 	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
@@ -2382,7 +2382,8 @@ static int files_rename_ref(const char *oldrefname, const char *newrefname,
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
-	symref = resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING,
+	resolve_flags = RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE;
+	symref = resolve_ref_unsafe(oldrefname, resolve_flags,
 				    orig_sha1, &flag);
 	if (flag & REF_ISSYMREF)
 		return error("refname %s is a symbolic ref, renaming it is not supported",
@@ -2402,8 +2403,8 @@ static int files_rename_ref(const char *oldrefname, const char *newrefname,
 		goto rollback;
 	}
 
-	if (!read_ref_full(newrefname, RESOLVE_REF_READING, sha1, NULL) &&
-	    delete_ref(newrefname, sha1, REF_NODEREF)) {
+	if (!read_ref_full(newrefname, resolve_flags, sha1, NULL) &&
+	    delete_ref(newrefname, NULL, REF_NODEREF)) {
 		if (errno==EISDIR) {
 			struct strbuf path = STRBUF_INIT;
 			int result;
@@ -2427,7 +2428,8 @@ static int files_rename_ref(const char *oldrefname, const char *newrefname,
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, 0, NULL, &err);
+	lock = lock_ref_sha1_basic(newrefname, NULL, NULL, NULL, REF_NODEREF,
+				   NULL, &err);
 	if (!lock) {
 		error("unable to rename '%s' to '%s': %s", oldrefname, newrefname, err.buf);
 		strbuf_release(&err);
@@ -2445,7 +2447,8 @@ static int files_rename_ref(const char *oldrefname, const char *newrefname,
 	return 0;
 
  rollback:
-	lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, 0, NULL, &err);
+	lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, NULL, REF_NODEREF,
+				   NULL, &err);
 	if (!lock) {
 		error("unable to lock %s for rollback: %s", oldrefname, err.buf);
 		strbuf_release(&err);
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index cdaf6f6..07e9749 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -79,6 +79,15 @@ test_expect_success 'git branch -m dumps usage' '
 	test_i18ngrep "branch name required" err
 '
 
+test_expect_success 'git branch -m m broken_symref should work' '
+	test_when_finished "git branch -D broken_symref" &&
+	git branch -l m &&
+	git symbolic-ref refs/heads/broken_symref refs/heads/i_am_broken &&
+	git branch -m m broken_symref &&
+	git reflog exists refs/heads/broken_symref &&
+	test_must_fail git reflog exists refs/heads/i_am_broken
+'
+
 test_expect_success 'git branch -m m m/m should work' '
 	git branch -l m &&
 	git branch -m m m/m &&
-- 
2.4.2.767.g62658d5-twtrsrc
Previous: David TurnerNext: David Turner
Message 27 of 56 in “refs backend”
  1. 00/32 refs backendDavid Turner, Feb 24, 2016
  2. 01/32 refs: move head_ref{,_submodule} to the common codeDavid Turner, Feb 24, 2016
  3. 02/32 refs: move for_each_*ref* functions into common codeDavid Turner, Feb 24, 2016
  4. 03/32 files-backend: break out ref readingDavid Turner, Feb 24, 2016
  5. Junio C HamanoFeb 25, 2016
  6. Junio C HamanoFeb 25, 2016
  7. David TurnerFeb 25, 2016
  8. Junio C HamanoFeb 25, 2016
  9. 04/32 refs: move resolve_ref_unsafe into common codeDavid Turner, Feb 24, 2016
  10. Junio C HamanoFeb 25, 2016
  11. 05/32 refs: add a backend method structure with transaction functionsDavid Turner, Feb 24, 2016
  12. Jeff KingFeb 27, 2016
  13. David TurnerFeb 29, 2016
  14. 06/32 refs: add methods for misc ref operationsDavid Turner, Feb 24, 2016
  15. 07/32 refs: add method for do_for_each_refDavid Turner, Feb 24, 2016
  16. 08/32 refs: reduce the visibility of do_for_each_ref()David Turner, Feb 24, 2016
  17. 09/32 refs: add do_for_each_per_worktree_refDavid Turner, Feb 24, 2016
  18. 10/32 refs: add methods for reflogDavid Turner, Feb 24, 2016
  19. 11/32 refs: add method for initial ref transaction commitDavid Turner, Feb 24, 2016
  20. 12/32 refs: add method for delete_refsDavid Turner, Feb 24, 2016
  21. 13/32 refs: add methods to init refs dbDavid Turner, Feb 24, 2016
  22. 14/32 refs: add method to rename refsDavid Turner, Feb 24, 2016
  23. 15/32 refs: handle non-normal ref renamesDavid Turner, Feb 24, 2016
  24. 16/32 refs: make lock genericDavid Turner, Feb 24, 2016
  25. 17/32 refs: move duplicate check to common codeDavid Turner, Feb 24, 2016
  26. 18/32 refs: allow log-only updatesDavid Turner, Feb 24, 2016
  27. 19/32 refs: don't dereference on renameDavid Turner, Feb 24, 2016
  28. 20/32 refs: on symref reflog expire, lock symref not referrentDavid Turner, Feb 24, 2016
  29. 21/32 refs: resolve symbolic refs firstDavid Turner, Feb 24, 2016
  30. 22/32 refs: always handle non-normal refs in files backendDavid Turner, Feb 24, 2016
  31. 23/32 init: allow alternate ref strorage to be set for new reposDavid Turner, Feb 24, 2016
  32. 24/32 refs: check submodules' ref storage configDavid Turner, Feb 24, 2016
  33. 25/32 clone: allow ref storage backend to be set for cloneDavid Turner, Feb 24, 2016
  34. 26/32 svn: learn ref-storage argumentDavid Turner, Feb 24, 2016
  35. 27/32 refs: register ref storage backendsDavid Turner, Feb 24, 2016
  36. 28/32 config: read ref storage config on startupDavid Turner, Feb 24, 2016
  37. Jeff KingFeb 27, 2016
  38. Jeff KingFeb 27, 2016
  39. David TurnerFeb 29, 2016
  40. Jeff KingFeb 29, 2016
  41. David TurnerFeb 29, 2016
  42. Jeff KingFeb 29, 2016
  43. Jeff KingFeb 29, 2016
  44. David TurnerFeb 29, 2016
  45. 29/32 refs: break out resolve_ref_unsafe_submoduleDavid Turner, Feb 24, 2016
  46. 30/32 refs: add LMDB refs storage backendDavid Turner, Feb 24, 2016
  47. 31/32 refs: tests for lmdb backendDavid Turner, Feb 24, 2016
  48. 32/32 tests: add ref-storage argumentDavid Turner, Feb 24, 2016
  49. SZEDER GáborFeb 29, 2016
  50. David TurnerFeb 29, 2016
  51. Ramsay JonesFeb 25, 2016
  52. David TurnerFeb 25, 2016
  53. Duy NguyenFeb 25, 2016
  54. David TurnerFeb 25, 2016
  55. Stefan BellerFeb 25, 2016
  56. Duy NguyenFeb 25, 2016

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