merge-ort: fix bug with renormalization and rename/delete conflicts

Ever since commit a492d5331c ("merge-ort: ensure we consult df_conflict
and path_conflicts", 2021-06-30), when renormalization is active AND a
file is involved in a rename/delete conflict BUT the file is unmodified
(either before or after renormalization), merge-ort was running into an
assertion failure.  Prior to that commit (or if assertions were compiled
out), merge-ort would mis-merge instead, ignoring the rename/delete
conflict and just deleting the file.

Remove the assertions, fix the code appropriately, leave some good
comments in the code, and add a testcase for this situation.

Reported-by: Ralf Thielow <ralf.thielow@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/t/t6418-merge-text-auto.sh b/t/t6418-merge-text-auto.sh
index 1e0296dd17..41288a60ce 100755
--- a/t/t6418-merge-text-auto.sh
+++ b/t/t6418-merge-text-auto.sh
@@ -204,4 +204,30 @@ test_expect_success 'Test delete/normalize conflict' '
 	test_path_is_missing file
 '
 
+test_expect_success 'rename/delete vs. renormalization' '
+	git init subrepo &&
+	(
+		cd subrepo &&
+		echo foo >oldfile &&
+		git add oldfile &&
+		git commit -m original &&
+
+		git branch rename &&
+		git branch nuke &&
+
+		git checkout rename &&
+		git mv oldfile newfile &&
+		git commit -m renamed &&
+
+		git checkout nuke &&
+		git rm oldfile &&
+		git commit -m deleted &&
+
+		git checkout rename^0 &&
+		test_must_fail git -c merge.renormalize=true merge nuke >out &&
+
+		grep "rename/delete" out
+	)
+'
+
 test_done