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[PATCH v2 03/14] rebase: pass correct arguments to post-checkout hook

From
PGPhillip Wood via GitGitGadget <gitgitgadget@gmail.com>
Date
Dec 8, 2021, 14:57 UTC
Message-ID
<07867760e68a6b28f718bdcb33094461592affaa.1638975482.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.1049.v2.git.1638975481.gitgitgadget@gmail.com>
From: Phillip Wood <phillip.wood@dunelm.org.uk>

If a rebase started with "rebase [--apply|--merge] <upstream> <branch>" detects that <upstream> is an ancestor of <branch> then it fast-forwards and checks out <branch>. Unfortunately in that case it passed the null oid as the first argument to the post-checkout hook rather than the oid of HEAD.

A side effect of this change is that the call to update_ref() which updates HEAD now always receives the old value of HEAD. This provides protection against another process updating HEAD during the checkout.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
 reset.c                       | 18 +++++++++---------
 t/t5403-post-checkout-hook.sh | 13 +++++++++++++
 2 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/reset.c b/reset.c
index f214df3d96c..315fef91d33 100644
--- a/reset.c
+++ b/reset.c
@@ -18,7 +18,7 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
 	unsigned run_hook = flags & RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
 	unsigned refs_only = flags & RESET_HEAD_REFS_ONLY;
 	unsigned update_orig_head = flags & RESET_ORIG_HEAD;
-	struct object_id head_oid;
+	struct object_id *head = NULL, head_oid;
 	struct tree_desc desc[2] = { { NULL }, { NULL } };
 	struct lock_file lock = LOCK_INIT;
 	struct unpack_trees_options unpack_tree_opts = { 0 };
@@ -26,8 +26,7 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
 	const char *reflog_action;
 	struct strbuf msg = STRBUF_INIT;
 	size_t prefix_len;
-	struct object_id *orig = NULL, oid_orig,
-		*old_orig = NULL, oid_old_orig;
+	struct object_id *old_orig = NULL, oid_old_orig;
 	int ret = 0, nr = 0;
 
 	if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
@@ -38,7 +37,9 @@ int reset_head(struct repository *r, struct object_id *oid, const char *action,
 		goto leave_reset_head;
 	}
 
-	if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
+	if (!get_oid("HEAD", &head_oid)) {
+		head = &head_oid;
+	} else if (!oid || !reset_hard) {
 		ret = error(_("could not determine HEAD revision"));
 		goto leave_reset_head;
 	}
@@ -98,13 +99,12 @@ reset_head_refs:
 	if (update_orig_head) {
 		if (!get_oid("ORIG_HEAD", &oid_old_orig))
 			old_orig = &oid_old_orig;
-		if (!get_oid("HEAD", &oid_orig)) {
-			orig = &oid_orig;
+		if (head) {
 			if (!reflog_orig_head) {
 				strbuf_addstr(&msg, "updating ORIG_HEAD");
 				reflog_orig_head = msg.buf;
 			}
-			update_ref(reflog_orig_head, "ORIG_HEAD", orig,
+			update_ref(reflog_orig_head, "ORIG_HEAD", head,
 				   old_orig, 0, UPDATE_REFS_MSG_ON_ERR);
 		} else if (old_orig)
 			delete_ref(NULL, "ORIG_HEAD", old_orig, 0);
@@ -116,7 +116,7 @@ reset_head_refs:
 		reflog_head = msg.buf;
 	}
 	if (!switch_to_branch)
-		ret = update_ref(reflog_head, "HEAD", oid, orig,
+		ret = update_ref(reflog_head, "HEAD", oid, head,
 				 detach_head ? REF_NO_DEREF : 0,
 				 UPDATE_REFS_MSG_ON_ERR);
 	else {
@@ -128,7 +128,7 @@ reset_head_refs:
 	}
 	if (run_hook)
 		run_hook_le(NULL, "post-checkout",
-			    oid_to_hex(orig ? orig : null_oid()),
+			    oid_to_hex(head ? head : null_oid()),
 			    oid_to_hex(oid), "1", NULL);
 
 leave_reset_head:
diff --git a/t/t5403-post-checkout-hook.sh b/t/t5403-post-checkout-hook.sh
index 272b02687ba..17ab518f268 100755
--- a/t/t5403-post-checkout-hook.sh
+++ b/t/t5403-post-checkout-hook.sh
@@ -72,6 +72,19 @@ test_rebase () {
 		test_cmp_rev rebase-on-me $new &&
 		test $flag = 1
 	'
+
+	test_expect_success "rebase $args fast-forward branch checkout runs post-checkout hook" '
+		test_when_finished "test_might_fail git rebase --abort" &&
+		test_when_finished "rm -f .git/post-checkout.args" &&
+		git update-ref refs/heads/rebase-fast-forward three &&
+		git checkout two  &&
+		rm -f .git/post-checkout.args &&
+		git rebase $args HEAD rebase-fast-forward  &&
+		read old new flag <.git/post-checkout.args &&
+		test_cmp_rev two $old &&
+		test_cmp_rev three $new &&
+		test $flag = 1
+	'
 }
 
 test_rebase --apply &&
-- 
gitgitgadget
Previous: Junio C HamanoNext: Junio C Hamano
Message 42 of 85 in “rebase: reset_head() related fixes and improvements”
  1. 00/11 rebase: reset_head() related fixes and improvementsPhillip Wood via GitGitGadget, Oct 1, 2021
  2. 01/11 rebase: factor out checkout for up to date branchPhillip Wood via GitGitGadget, Oct 1, 2021
  3. 03/11 reset_head(): don't run checkout hook if there is an errorPhillip Wood via GitGitGadget, Oct 1, 2021
  4. Junio C HamanoOct 1, 2021
  5. Phillip WoodOct 4, 2021
  6. Ævar Arnfjörð BjarmasonOct 12, 2021
  7. 04/11 reset_head(): remove action parameterPhillip Wood via GitGitGadget, Oct 1, 2021
  8. Junio C HamanoOct 1, 2021
  9. Phillip WoodOct 4, 2021
  10. 05/11 reset_head(): factor out ref updatesPhillip Wood via GitGitGadget, Oct 1, 2021
  11. Junio C HamanoOct 1, 2021
  12. Phillip WoodOct 4, 2021
  13. 06/11 reset_head(): make default_reflog_action optionalPhillip Wood via GitGitGadget, Oct 1, 2021
  14. Junio C HamanoOct 1, 2021
  15. Junio C HamanoOct 1, 2021
  16. Phillip WoodOct 4, 2021
  17. 09/11 rebase --apply: fix reflogPhillip Wood via GitGitGadget, Oct 1, 2021
  18. Junio C HamanoOct 1, 2021
  19. 08/11 reset_head(): take struct rebase_head_optsPhillip Wood via GitGitGadget, Oct 1, 2021
  20. Junio C HamanoOct 1, 2021
  21. Phillip WoodOct 4, 2021
  22. 10/11 rebase --apply: set ORIG_HEAD correctlyPhillip Wood via GitGitGadget, Oct 1, 2021
  23. Junio C HamanoOct 1, 2021
  24. 02/11 reset_head(): fix checkoutPhillip Wood via GitGitGadget, Oct 1, 2021
  25. Junio C HamanoOct 1, 2021
  26. Phillip WoodOct 4, 2021
  27. Junio C HamanoOct 4, 2021
  28. Eric SunshineOct 1, 2021
  29. 11/11 rebase -m: don't fork git checkoutPhillip Wood via GitGitGadget, Oct 1, 2021
  30. 07/11 rebase: cleanup reset_head() callsPhillip Wood via GitGitGadget, Oct 1, 2021
  31. Junio C HamanoOct 2, 2021
  32. Junio C HamanoOct 2, 2021
  33. Phillip WoodOct 2, 2021
  34. Phillip WoodOct 2, 2021
  35. René ScharfeOct 2, 2021
  36. Phillip WoodOct 6, 2021
  37. 00/14 rebase: reset_head() related fixes and improvementsPhillip Wood via GitGitGadget, Dec 8, 2021
  38. 01/14 rebase: factor out checkout for up to date branchPhillip Wood via GitGitGadget, Dec 8, 2021
  39. Junio C HamanoDec 9, 2021
  40. 02/14 t5403: refactor rebase post-checkout hook testsPhillip Wood via GitGitGadget, Dec 8, 2021
  41. Junio C HamanoDec 9, 2021
  42. 03/14 rebase: pass correct arguments to post-checkout hookPhillip Wood via GitGitGadget, Dec 8, 2021
  43. Junio C HamanoDec 9, 2021
  44. 04/14 rebase: do not remove untracked files on checkoutPhillip Wood via GitGitGadget, Dec 8, 2021
  45. Junio C HamanoDec 9, 2021
  46. 05/14 rebase --apply: don't run post-checkout hook if there is an errorPhillip Wood via GitGitGadget, Dec 8, 2021
  47. 06/14 reset_head(): remove action parameterPhillip Wood via GitGitGadget, Dec 8, 2021
  48. 07/14 create_autostash(): remove unneeded parameterPhillip Wood via GitGitGadget, Dec 8, 2021
  49. Junio C HamanoDec 9, 2021
  50. Phillip WoodJan 25, 2022
  51. 08/14 reset_head(): factor out ref updatesPhillip Wood via GitGitGadget, Dec 8, 2021
  52. 09/14 reset_head(): make default_reflog_action optionalPhillip Wood via GitGitGadget, Dec 8, 2021
  53. Junio C HamanoDec 9, 2021
  54. 10/14 rebase: cleanup reset_head() callsPhillip Wood via GitGitGadget, Dec 8, 2021
  55. Junio C HamanoDec 9, 2021
  56. Phillip WoodJan 25, 2022
  57. 11/14 reset_head(): take struct rebase_head_optsPhillip Wood via GitGitGadget, Dec 8, 2021
  58. Junio C HamanoDec 9, 2021
  59. 12/14 rebase --apply: fix reflogPhillip Wood via GitGitGadget, Dec 8, 2021
  60. Junio C HamanoDec 9, 2021
  61. 13/14 rebase --apply: set ORIG_HEAD correctlyPhillip Wood via GitGitGadget, Dec 8, 2021
  62. Elijah NewrenDec 11, 2021
  63. 14/14 rebase -m: don't fork git checkoutPhillip Wood via GitGitGadget, Dec 8, 2021
  64. Junio C HamanoDec 9, 2021
  65. Phillip WoodJan 26, 2022
  66. Junio C HamanoJan 27, 2022
  67. Elijah NewrenDec 11, 2021
  68. 00/14 rebase: reset_head() related fixes and improvementsPhillip Wood via GitGitGadget, Jan 26, 2022
  69. 01/14 rebase: factor out checkout for up to date branchPhillip Wood via GitGitGadget, Jan 26, 2022
  70. 02/14 t5403: refactor rebase post-checkout hook testsPhillip Wood via GitGitGadget, Jan 26, 2022
  71. 03/14 rebase: pass correct arguments to post-checkout hookPhillip Wood via GitGitGadget, Jan 26, 2022
  72. 04/14 rebase: do not remove untracked files on checkoutPhillip Wood via GitGitGadget, Jan 26, 2022
  73. 05/14 rebase --apply: don't run post-checkout hook if there is an errorPhillip Wood via GitGitGadget, Jan 26, 2022
  74. 06/14 reset_head(): remove action parameterPhillip Wood via GitGitGadget, Jan 26, 2022
  75. 07/14 reset_head(): factor out ref updatesPhillip Wood via GitGitGadget, Jan 26, 2022
  76. 08/14 reset_head(): make default_reflog_action optionalPhillip Wood via GitGitGadget, Jan 26, 2022
  77. 09/14 create_autostash(): remove unneeded parameterPhillip Wood via GitGitGadget, Jan 26, 2022
  78. 10/14 rebase: cleanup reset_head() callsPhillip Wood via GitGitGadget, Jan 26, 2022
  79. 11/14 reset_head(): take struct rebase_head_optsPhillip Wood via GitGitGadget, Jan 26, 2022
  80. Ævar Arnfjörð BjarmasonJan 26, 2022
  81. Phillip WoodJan 26, 2022
  82. 12/14 rebase --apply: fix reflogPhillip Wood via GitGitGadget, Jan 26, 2022
  83. 13/14 rebase --apply: set ORIG_HEAD correctlyPhillip Wood via GitGitGadget, Jan 26, 2022
  84. 14/14 rebase -m: don't fork git checkoutPhillip Wood via GitGitGadget, Jan 26, 2022
  85. Elijah NewrenFeb 1, 2022

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