t6036: add a failed conflict detection case with submodule modify/modify

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6036-recursive-corner-cases.sh
index 0ba04d46da18c71e35c16de6870067c17b4a7f64..0c8f81331aaf301590606e13e1a25dfd9adbc748 100755 (executable)
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6036-recursive-corner-cases.sh
@@ -938,4 +938,92 @@ test_expect_failure 'check symlink add/add' '
        )
 '
 
+#
+# criss-cross with modify/modify on a submodule:
+#
+#      B   D
+#      o---o
+#     / \ / \
+#  A o   X   ? F
+#     \ / \ /
+#      o---o
+#      C   E
+#
+#   Commit A: simple submodule repo
+#   Commit B: update repo
+#   Commit C: update repo differently
+#   Commit D: merge B&C, resolving in favor of B
+#   Commit E: merge B&C, resolving in favor of C
+#
+# This is an obvious modify/modify conflict for the submodule 'repo'.  Can
+# git detect it?
+
+test_expect_success 'setup submodule modify/modify' '
+       test_create_repo submodule-modify-modify &&
+       (
+               cd submodule-modify-modify &&
+
+               test_create_repo submod &&
+               (
+                       cd submod &&
+                       touch file-A &&
+                       git add file-A &&
+                       git commit -m A &&
+                       git tag A &&
+
+                       git checkout -b B A &&
+                       touch file-B &&
+                       git add file-B &&
+                       git commit -m B &&
+                       git tag B &&
+
+                       git checkout -b C A &&
+                       touch file-C &&
+                       git add file-C &&
+                       git commit -m C &&
+                       git tag C
+               ) &&
+
+               git -C submod reset --hard A &&
+               git add submod &&
+               git commit -m A &&
+               git tag A &&
+
+               git checkout -b B A &&
+               git -C submod reset --hard B &&
+               git add submod &&
+               git commit -m B &&
+
+               git checkout -b C A &&
+               git -C submod reset --hard C &&
+               git add submod &&
+               git commit -m C &&
+
+               git checkout -q B^0 &&
+               git merge -s ours -m D C^0 &&
+               git tag D &&
+
+               git checkout -q C^0 &&
+               git merge -s ours -m E B^0 &&
+               git tag E
+       )
+'
+
+test_expect_failure 'check submodule modify/modify' '
+       (
+               cd submodule-modify-modify &&
+
+               git checkout D^0 &&
+
+               test_must_fail git merge -s recursive E^0 &&
+
+               git ls-files -s >out &&
+               test_line_count = 3 out &&
+               git ls-files -u >out &&
+               test_line_count = 3 out &&
+               git ls-files -o >out &&
+               test_line_count = 1 out
+       )
+'
+
 test_done