t6036, t6042: testcases for rename collision of already conflicting files

When a single file is renamed, it can also be modified, yielding the
possibility of that renamed file having content conflicts.  If two
different such files are renamed into the same location, then two-way
merging those files may result in nested conflicts.  Add a testcase that
makes sure we get this case correct, and uses different lengths of
conflict markers to differentiate between the different nestings.

Also add another case with an extra (i.e. third) level of conflict
markers due to using merge.conflictstyle=diff3 and the virtual merge
base also having conflicts present.

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

1 files changed, 118 insertions, 0 deletions

diff --git a/t/t6042-merge-rename-corner-cases.sh b/t/t6042-merge-rename-corner-cases.sh
index b6fed2cb9a..23c3b6dffa 100755
--- a/t/t6042-merge-rename-corner-cases.sh
+++ b/t/t6042-merge-rename-corner-cases.sh
@@ -1099,4 +1099,122 @@ test_conflicts_with_adds_and_renames rename add    failure
 test_conflicts_with_adds_and_renames add    rename failure
 test_conflicts_with_adds_and_renames add    add    success
 
+# Setup:
+#          L
+#         / \
+#   master   ?
+#         \ /
+#          R
+#
+# Where:
+#   master has two files, named 'one' and 'two'.
+#   branches L and R both modify 'one', in conflicting ways.
+#   branches L and R both modify 'two', in conflicting ways.
+#   branch L also renames 'one' to 'three'.
+#   branch R also renames 'two' to 'three'.
+#
+#   So, we have four different conflicting files that all end up at path
+#   'three'.
+test_expect_success 'setup nested conflicts from rename/rename(2to1)' '
+	test_create_repo nested_conflicts_from_rename_rename &&
+	(
+		cd nested_conflicts_from_rename_rename &&
+
+		# Create some related files now
+		for i in $(test_seq 1 10)
+		do
+			echo Random base content line $i
+		done >file_v1 &&
+
+		cp file_v1 file_v2 &&
+		cp file_v1 file_v3 &&
+		cp file_v1 file_v4 &&
+		cp file_v1 file_v5 &&
+		cp file_v1 file_v6 &&
+
+		echo one  >>file_v1 &&
+		echo uno  >>file_v2 &&
+		echo eins >>file_v3 &&
+
+		echo two  >>file_v4 &&
+		echo dos  >>file_v5 &&
+		echo zwei >>file_v6 &&
+
+		# Setup original commit (or merge-base), consisting of
+		# files named "one" and "two".
+		mv file_v1 one &&
+		mv file_v4 two &&
+		git add one two &&
+		test_tick && git commit -m english &&
+
+		git branch L &&
+		git branch R &&
+
+		# Handle the left side
+		git checkout L &&
+		git mv one three &&
+		mv -f file_v2 three &&
+		mv -f file_v5 two &&
+		git add two three &&
+		test_tick && git commit -m spanish &&
+
+		# Handle the right side
+		git checkout R &&
+		git mv two three &&
+		mv -f file_v3 one &&
+		mv -f file_v6 three &&
+		git add one three &&
+		test_tick && git commit -m german
+	)
+'
+
+test_expect_failure 'check nested conflicts from rename/rename(2to1)' '
+	(
+		cd nested_conflicts_from_rename_rename &&
+
+		git checkout L^0 &&
+
+		# Merge must fail; there is a conflict
+		test_must_fail git merge -s recursive R^0 &&
+
+		# Make sure the index has the right number of entries
+		git ls-files -s >out &&
+		test_line_count = 2 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		# Ensure we have the correct number of untracked files
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		# Compare :2:three to expected values
+		git cat-file -p master:one >base &&
+		git cat-file -p L:three >ours &&
+		git cat-file -p R:one >theirs &&
+		test_must_fail git merge-file    \
+			-L "HEAD:three"  -L ""  -L "R^0:one" \
+			ours             base   theirs &&
+		sed -e "s/^\([<=>]\)/\1\1/" ours >L-three &&
+		git cat-file -p :2:three >expect &&
+		test_cmp expect L-three &&
+
+		# Compare :2:three to expected values
+		git cat-file -p master:two >base &&
+		git cat-file -p L:two >ours &&
+		git cat-file -p R:three >theirs &&
+		test_must_fail git merge-file    \
+			-L "HEAD:two"  -L ""  -L "R^0:three" \
+			ours           base   theirs &&
+		sed -e "s/^\([<=>]\)/\1\1/" ours >R-three &&
+		git cat-file -p :3:three >expect &&
+		test_cmp expect R-three &&
+
+		# Compare three to expected contents
+		>empty &&
+		test_must_fail git merge-file    \
+			-L "HEAD"  -L ""  -L "R^0" \
+			L-three    empty  R-three &&
+		test_cmp three L-three
+	)
+'
+
 test_done