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Re: [PATCH v4 1/1] rebase: --fork-point regression fix

From
Junio C Hamano <gitster@pobox.com>
Date
Feb 11, 2020, 18:15 UTC
Message-ID
<xmqq5zgdvvlq.fsf@gitster-ct.c.googlers.com>
In-Reply-To
<CAPig+cQ-3Ds41hr91fRo_GvuFMTP7zNVJtaSqi-Yccq4Pk-8Qg@mail.gmail.com>

"git rebase --fork-point master" used to work OK, as it internally called "git merge-base --fork-point" that knew how to handle short refname and dwim it to the full refname before calling the underlying get_fork_point() function.

This is no longer true after the command was rewritten in C, as its internall call made directly to get_fork_point() does not dwim a short ref.

Move the "dwim the refname argument to the full refname" logic that is used in "git merge-base" to the underlying get_fork_point() function, so that the other caller of the function in the implementation of "git rebase" behaves the same way to fix this regression.

Signed-off-by: Alex Torok <alext9@gmail.com>
[jc: revamped the fix and used Alex's tests]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 * I was about to discard stalled topics and this caught my eyes.
 builtin/merge-base.c         | 12 +-----------
 commit.c                     | 15 +++++++++++++--
 t/t3431-rebase-fork-point.sh | 20 ++++++++++++++++++++
 3 files changed, 34 insertions(+), 13 deletions(-)
diff --git a/builtin/merge-base.c b/builtin/merge-base.c
index e3f8da13b6..6719ac198d 100644
--- a/builtin/merge-base.c
+++ b/builtin/merge-base.c
@@ -114,26 +114,16 @@ static int handle_is_ancestor(int argc, const char **argv)
 static int handle_fork_point(int argc, const char **argv)
 {
 	struct object_id oid;
-	char *refname;
 	struct commit *derived, *fork_point;
 	const char *commitname;
 
-	switch (dwim_ref(argv[0], strlen(argv[0]), &oid, &refname)) {
-	case 0:
-		die("No such ref: '%s'", argv[0]);
-	case 1:
-		break; /* good */
-	default:
-		die("Ambiguous refname: '%s'", argv[0]);
-	}
-
 	commitname = (argc == 2) ? argv[1] : "HEAD";
 	if (get_oid(commitname, &oid))
 		die("Not a valid object name: '%s'", commitname);
 
 	derived = lookup_commit_reference(the_repository, &oid);
 
-	fork_point = get_fork_point(refname, derived);
+	fork_point = get_fork_point(argv[0], derived);
 
 	if (!fork_point)
 		return 1;
diff --git a/commit.c b/commit.c
index 40890ae7ce..016f14fe95 100644
--- a/commit.c
+++ b/commit.c
@@ -903,12 +903,22 @@ struct commit *get_fork_point(const char *refname, struct commit *commit)
 	struct commit_list *bases;
 	int i;
 	struct commit *ret = NULL;
+	char *full_refname;
+
+	switch (dwim_ref(refname, strlen(refname), &oid, &full_refname)) {
+	case 0:
+		die("No such ref: '%s'", refname);
+	case 1:
+		break; /* good */
+	default:
+		die("Ambiguous refname: '%s'", refname);
+	}
 
 	memset(&revs, 0, sizeof(revs));
 	revs.initial = 1;
-	for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
+	for_each_reflog_ent(full_refname, collect_one_reflog_ent, &revs);
 
-	if (!revs.nr && !get_oid(refname, &oid))
+	if (!revs.nr)
 		add_one_commit(&oid, &revs);
 
 	for (i = 0; i < revs.nr; i++)
@@ -934,6 +944,7 @@ struct commit *get_fork_point(const char *refname, struct commit *commit)
 
 cleanup_return:
 	free_commit_list(bases);
+	free(full_refname);
 	return ret;
 }
 
diff --git a/t/t3431-rebase-fork-point.sh b/t/t3431-rebase-fork-point.sh
index 78851b9a2a..172562789e 100755
--- a/t/t3431-rebase-fork-point.sh
+++ b/t/t3431-rebase-fork-point.sh
@@ -47,11 +47,31 @@ test_rebase 'G F B A' --keep-base
 test_rebase 'G F C E D B A' --no-fork-point
 test_rebase 'G F C D B A' --no-fork-point --onto D
 test_rebase 'G F C B A' --no-fork-point --keep-base
+
 test_rebase 'G F E D B A' --fork-point refs/heads/master
+test_rebase 'G F E D B A' --fork-point master
+
 test_rebase 'G F D B A' --fork-point --onto D refs/heads/master
+test_rebase 'G F D B A' --fork-point --onto D master
+
 test_rebase 'G F B A' --fork-point --keep-base refs/heads/master
+test_rebase 'G F B A' --fork-point --keep-base master
+
 test_rebase 'G F C E D B A' refs/heads/master
+test_rebase 'G F C E D B A' master
+
 test_rebase 'G F C D B A' --onto D refs/heads/master
+test_rebase 'G F C D B A' --onto D master
+
 test_rebase 'G F C B A' --keep-base refs/heads/master
+test_rebase 'G F C B A' --keep-base master
+
+test_expect_success 'git rebase --fork-point with ambigous refname' '
+	git checkout master &&
+	git checkout -b one &&
+	git checkout side &&
+	git tag one &&
+	test_must_fail git rebase --fork-point --onto D one
+'
 
 test_done
Previous: Eric Sunshine
Message 23 of 23 in “rebase: fix bug in --fork-point”
  1. 0/3 rebase: fix bug in --fork-pointAlex Torok, Dec 5, 2019
  2. 1/3 rebase: add test for rebase --fork-point with short upstreamAlex Torok, Dec 5, 2019
  3. Junio C HamanoDec 5, 2019
  4. Alex TorokDec 5, 2019
  5. 2/3 rebase: refactor dwim_ref_or_die from merge-base.cAlex Torok, Dec 5, 2019
  6. 3/3 rebase: fix rebase to use full ref to find fork-pointAlex Torok, Dec 5, 2019
  7. 0/2 rebase: fix bug in --fork-pointAlex Torok, Dec 5, 2019
  8. 1/2 rebase: refactor dwim_ref_or_die from merge-base.cAlex Torok, Dec 5, 2019
  9. Denton LiuDec 6, 2019
  10. Alex TorokDec 6, 2019
  11. 2/2 rebase: find --fork-point with full refAlex Torok, Dec 5, 2019
  12. Denton LiuDec 6, 2019
  13. Phillip WoodDec 6, 2019
  14. Alex TorokDec 6, 2019
  15. Denton LiuDec 6, 2019
  16. Phillip WoodDec 6, 2019
  17. 0/1 rebase: fix --fork-point with short ref upstreamAlex Torok, Dec 9, 2019
  18. 1/1 rebase: fix --fork-point with short refnameAlex Torok, Dec 9, 2019
  19. Junio C HamanoDec 9, 2019
  20. Alex TorokDec 11, 2019
  21. Denton LiuDec 11, 2019
  22. Eric SunshineDec 11, 2019
  23. Junio C HamanoFeb 11, 2020

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