[PATCH 11/48] t6036: criss-cross w/ rename/rename(1to2)/modify+rename/rename(2to1)/modify

[Elijah Newren <newren@gmail.com>]

This test is mostly just designed for testing optimality of the virtual
merge base in the event of a rename/rename(1to2) conflict.  The current
choice for resolving this in git seems somewhat confusing and suboptimal.

Signed-off-by: Elijah Newren <newren@gmail.com>
---
 t/t6036-recursive-corner-cases.sh |   76 +++++++++++++++++++++++++++++++++++++
 1 files changed, 76 insertions(+), 0 deletions(-)

diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6036-recursive-corner-cases.sh
index 4993f67..eee183e 100755
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6036-recursive-corner-cases.sh
@@ -545,5 +545,81 @@ test_expect_failure 'git detects conflict and handles merge of E2 & D correctly'
 	test $(git rev-parse :1:a/file) = $(git rev-parse C:a/file)
 '
 
+#
+# criss-cross with rename/rename(1to2)/modify followed by
+# rename/rename(2to1)/modify:
+#
+#      B   D
+#      o---o
+#     / \ / \
+#  A o   X   ? F
+#     \ / \ /
+#      o---o
+#      C   E
+#
+#   Commit A: new file: a
+#   Commit B: rename a->b, modifying by adding a line
+#   Commit C: rename a->c
+#   Commit D: merge B&C, resolving conflict by keeping contents in newname
+#   Commit E: merge B&C, resolving conflict similar to D but adding another line
+#
+# There is a conflict merging B & C, but one of filename not of file
+# content.  Whoever created D and E chose specific resolutions for that
+# conflict resolution.  Now, since: (1) there is no content conflict
+# merging B & C, (2) D does not modify that merged content further, and (3)
+# both D & E resolve the name conflict in the same way, the modification to
+# newname in E should not cause any conflicts when it is merged with D.
+# (Note that this can be accomplished by having the virtual merge base have
+# the merged contents of b and c stored in a file named a, which seems like
+# the most logical choice anyway.)
+
+test_expect_success 'setup rename/rename(1to2)/modify followed by what looks like rename/rename(2to1)/modify' '
+	git reset --hard &&
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	printf "1\n2\n3\n4\n5\n6\n" >a &&
+	git add a &&
+	git commit -m A &&
+	git tag A &&
+
+	git checkout -b B A &&
+	git mv a b &&
+	echo 7 >>b &&
+	git add -u &&
+	git commit -m B &&
+
+	git checkout -b C A &&
+	git mv a c &&
+	git commit -m C &&
+
+	git checkout -q B^0 &&
+	git merge --no-commit -s ours C^0 &&
+	git mv b newname &&
+	git commit -m "Merge commit C^0 into HEAD" &&
+	git tag D &&
+
+	git checkout -q C^0 &&
+	git merge --no-commit -s ours B^0 &&
+	git mv c newname &&
+	printf "7\n8\n" >>newname &&
+	git add -u &&
+	git commit -m "Merge commit B^0 into HEAD" &&
+	git tag E
+'
+
+test_expect_failure 'handle rename/rename(1to2)/modify followed by what looks like rename/rename(2to1)/modify' '
+	git checkout D^0 &&
+
+	git merge -s recursive E^0 &&
+
+	test 1 -eq $(git ls-files -s | wc -l) &&
+	test 0 -eq $(git ls-files -u | wc -l) &&
+	test 0 -eq $(git ls-files -o | wc -l) &&
+
+	test 8 -eq $(wc -l < newname)
+'
 
 test_done
-- 
1.7.6.rc0.62.g2d69f