path: root/t/t6043-merge-rename-directories.sh

#!/bin/sh

test_description="recursive merge with directory renames"
# includes checking of many corner cases, with a similar methodology to:
#   t6042: corner cases with renames but not criss-cross merges
#   t6036: corner cases with both renames and criss-cross merges
#
# The setup for all of them, pictorially, is:
#
#      A
#      o
#     / \
#  O o   ?
#     \ /
#      o
#      B
#
# To help make it easier to follow the flow of tests, they have been
# divided into sections and each test will start with a quick explanation
# of what commits O, A, and B contain.
#
# Notation:
#    z/{b,c}   means  files z/b and z/c both exist
#    x/d_1     means  file x/d exists with content d1.  (Purpose of the
#                     underscore notation is to differentiate different
#                     files that might be renamed into each other's paths.)

. ./test-lib.sh


###########################################################################
# SECTION 1: Basic cases we should be able to handle
###########################################################################

# Testcase 1a, Basic directory rename.
#   Commit O: z/{b,c}
#   Commit A: y/{b,c}
#   Commit B: z/{b,c,d,e/f}
#   Expected: y/{b,c,d,e/f}

test_expect_success '1a-setup: Simple directory rename detection' '
	test_create_repo 1a &&
	(
		cd 1a &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git mv z y &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		echo d >z/d &&
		mkdir z/e &&
		echo f >z/e/f &&
		git add z/d z/e/f &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '1a-check: Simple directory rename detection' '
	(
		cd 1a &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 4 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:y/e/f &&
		git rev-parse >expect \
			O:z/b    O:z/c    B:z/d    B:z/e/f &&
		test_cmp expect actual &&

		git hash-object y/d >actual &&
		git rev-parse B:z/d >expect &&
		test_cmp expect actual &&

		test_must_fail git rev-parse HEAD:z/d &&
		test_must_fail git rev-parse HEAD:z/e/f &&
		test_path_is_missing z/d &&
		test_path_is_missing z/e/f
	)
'

# Testcase 1b, Merge a directory with another
#   Commit O: z/{b,c},   y/d
#   Commit A: z/{b,c,e}, y/d
#   Commit B: y/{b,c,d}
#   Expected: y/{b,c,d,e}

test_expect_success '1b-setup: Merge a directory with another' '
	test_create_repo 1b &&
	(
		cd 1b &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		mkdir y &&
		echo d >y/d &&
		git add z y &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		echo e >z/e &&
		git add z/e &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		git mv z/b y &&
		git mv z/c y &&
		rmdir z &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '1b-check: Merge a directory with another' '
	(
		cd 1b &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 4 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:y/e &&
		git rev-parse >expect \
			O:z/b    O:z/c    O:y/d    A:z/e &&
		test_cmp expect actual &&
		test_must_fail git rev-parse HEAD:z/e
	)
'

# Testcase 1c, Transitive renaming
#   (Related to testcases 3a and 6d -- when should a transitive rename apply?)
#   (Related to testcases 9c and 9d -- can transitivity repeat?)
#   Commit O: z/{b,c},   x/d
#   Commit A: y/{b,c},   x/d
#   Commit B: z/{b,c,d}
#   Expected: y/{b,c,d}  (because x/d -> z/d -> y/d)

test_expect_success '1c-setup: Transitive renaming' '
	test_create_repo 1c &&
	(
		cd 1c &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		mkdir x &&
		echo d >x/d &&
		git add z x &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git mv z y &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		git mv x/d z/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '1c-check: Transitive renaming' '
	(
		cd 1c &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 3 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:y/d &&
		git rev-parse >expect \
			O:z/b    O:z/c    O:x/d &&
		test_cmp expect actual &&
		test_must_fail git rev-parse HEAD:x/d &&
		test_must_fail git rev-parse HEAD:z/d &&
		test_path_is_missing z/d
	)
'

# Testcase 1d, Directory renames (merging two directories into one new one)
#              cause a rename/rename(2to1) conflict
#   (Related to testcases 1c and 7b)
#   Commit O. z/{b,c},        y/{d,e}
#   Commit A. x/{b,c},        y/{d,e,m,wham_1}
#   Commit B. z/{b,c,n,wham_2}, x/{d,e}
#   Expected: x/{b,c,d,e,m,n}, CONFLICT:(y/wham_1 & z/wham_2 -> x/wham)
#   Note: y/m & z/n should definitely move into x.  By the same token, both
#         y/wham_1 & z/wham_2 should too...giving us a conflict.

test_expect_success '1d-setup: Directory renames cause a rename/rename(2to1) conflict' '
	test_create_repo 1d &&
	(
		cd 1d &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		mkdir y &&
		echo d >y/d &&
		echo e >y/e &&
		git add z y &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git mv z x &&
		echo m >y/m &&
		echo wham1 >y/wham &&
		git add y &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		git mv y x &&
		echo n >z/n &&
		echo wham2 >z/wham &&
		git add z &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '1d-check: Directory renames cause a rename/rename(2to1) conflict' '
	(
		cd 1d &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT (rename/rename)" out &&

		git ls-files -s >out &&
		test_line_count = 8 out &&
		git ls-files -u >out &&
		test_line_count = 2 out &&
		git ls-files -o >out &&
		test_line_count = 3 out &&

		git rev-parse >actual \
			:0:x/b :0:x/c :0:x/d :0:x/e :0:x/m :0:x/n &&
		git rev-parse >expect \
			 O:z/b  O:z/c  O:y/d  O:y/e  A:y/m  B:z/n &&
		test_cmp expect actual &&

		test_must_fail git rev-parse :0:x/wham &&
		git rev-parse >actual \
			:2:x/wham :3:x/wham &&
		git rev-parse >expect \
			 A:y/wham  B:z/wham &&
		test_cmp expect actual &&

		test_path_is_missing x/wham &&
		test_path_is_file x/wham~HEAD &&
		test_path_is_file x/wham~B^0 &&

		git hash-object >actual \
			x/wham~HEAD x/wham~B^0 &&
		git rev-parse >expect \
			A:y/wham    B:z/wham &&
		test_cmp expect actual
	)
'

# Testcase 1e, Renamed directory, with all filenames being renamed too
#   Commit O: z/{oldb,oldc}
#   Commit A: y/{newb,newc}
#   Commit B: z/{oldb,oldc,d}
#   Expected: y/{newb,newc,d}

test_expect_success '1e-setup: Renamed directory, with all files being renamed too' '
	test_create_repo 1e &&
	(
		cd 1e &&

		mkdir z &&
		echo b >z/oldb &&
		echo c >z/oldc &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		mkdir y &&
		git mv z/oldb y/newb &&
		git mv z/oldc y/newc &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		echo d >z/d &&
		git add z/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '1e-check: Renamed directory, with all files being renamed too' '
	(
		cd 1e &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 3 out &&

		git rev-parse >actual \
			HEAD:y/newb HEAD:y/newc HEAD:y/d &&
		git rev-parse >expect \
			O:z/oldb    O:z/oldc    B:z/d &&
		test_cmp expect actual &&
		test_must_fail git rev-parse HEAD:z/d
	)
'

# Testcase 1f, Split a directory into two other directories
#   (Related to testcases 3a, all of section 2, and all of section 4)
#   Commit O: z/{b,c,d,e,f}
#   Commit A: z/{b,c,d,e,f,g}
#   Commit B: y/{b,c}, x/{d,e,f}
#   Expected: y/{b,c}, x/{d,e,f,g}

test_expect_success '1f-setup: Split a directory into two other directories' '
	test_create_repo 1f &&
	(
		cd 1f &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		echo d >z/d &&
		echo e >z/e &&
		echo f >z/f &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		echo g >z/g &&
		git add z/g &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		mkdir y &&
		mkdir x &&
		git mv z/b y/ &&
		git mv z/c y/ &&
		git mv z/d x/ &&
		git mv z/e x/ &&
		git mv z/f x/ &&
		rmdir z &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '1f-check: Split a directory into two other directories' '
	(
		cd 1f &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 6 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:x/d HEAD:x/e HEAD:x/f HEAD:x/g &&
		git rev-parse >expect \
			O:z/b    O:z/c    O:z/d    O:z/e    O:z/f    A:z/g &&
		test_cmp expect actual &&
		test_path_is_missing z/g &&
		test_must_fail git rev-parse HEAD:z/g
	)
'

###########################################################################
# Rules suggested by testcases in section 1:
#
#   We should still detect the directory rename even if it wasn't just
#   the directory renamed, but the files within it. (see 1b)
#
#   If renames split a directory into two or more others, the directory
#   with the most renames, "wins" (see 1c).  However, see the testcases
#   in section 2, plus testcases 3a and 4a.
###########################################################################


###########################################################################
# SECTION 2: Split into multiple directories, with equal number of paths
#
# Explore the splitting-a-directory rules a bit; what happens in the
# edge cases?
#
# Note that there is a closely related case of a directory not being
# split on either side of history, but being renamed differently on
# each side.  See testcase 8e for that.
###########################################################################

# Testcase 2a, Directory split into two on one side, with equal numbers of paths
#   Commit O: z/{b,c}
#   Commit A: y/b, w/c
#   Commit B: z/{b,c,d}
#   Expected: y/b, w/c, z/d, with warning about z/ -> (y/ vs. w/) conflict
test_expect_success '2a-setup: Directory split into two on one side, with equal numbers of paths' '
	test_create_repo 2a &&
	(
		cd 2a &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		mkdir y &&
		mkdir w &&
		git mv z/b y/ &&
		git mv z/c w/ &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		echo d >z/d &&
		git add z/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '2a-check: Directory split into two on one side, with equal numbers of paths' '
	(
		cd 2a &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT.*directory rename split" out &&

		git ls-files -s >out &&
		test_line_count = 3 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			:0:y/b :0:w/c :0:z/d &&
		git rev-parse >expect \
			 O:z/b  O:z/c  B:z/d &&
		test_cmp expect actual
	)
'

# Testcase 2b, Directory split into two on one side, with equal numbers of paths
#   Commit O: z/{b,c}
#   Commit A: y/b, w/c
#   Commit B: z/{b,c}, x/d
#   Expected: y/b, w/c, x/d; No warning about z/ -> (y/ vs. w/) conflict
test_expect_success '2b-setup: Directory split into two on one side, with equal numbers of paths' '
	test_create_repo 2b &&
	(
		cd 2b &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		mkdir y &&
		mkdir w &&
		git mv z/b y/ &&
		git mv z/c w/ &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		mkdir x &&
		echo d >x/d &&
		git add x/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '2b-check: Directory split into two on one side, with equal numbers of paths' '
	(
		cd 2b &&

		git checkout A^0 &&

		git merge -s recursive B^0 >out &&

		git ls-files -s >out &&
		test_line_count = 3 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			:0:y/b :0:w/c :0:x/d &&
		git rev-parse >expect \
			 O:z/b  O:z/c  B:x/d &&
		test_cmp expect actual &&
		test_i18ngrep ! "CONFLICT.*directory rename split" out
	)
'

###########################################################################
# Rules suggested by section 2:
#
#   None; the rule was already covered in section 1.  These testcases are
#   here just to make sure the conflict resolution and necessary warning
#   messages are handled correctly.
###########################################################################


###########################################################################
# SECTION 3: Path in question is the source path for some rename already
#
# Combining cases from Section 1 and trying to handle them could lead to
# directory renaming detection being over-applied.  So, this section
# provides some good testcases to check that the implementation doesn't go
# too far.
###########################################################################

# Testcase 3a, Avoid implicit rename if involved as source on other side
#   (Related to testcases 1c and 1f)
#   Commit O: z/{b,c,d}
#   Commit A: z/{b,c,d} (no change)
#   Commit B: y/{b,c}, x/d
#   Expected: y/{b,c}, x/d
test_expect_success '3a-setup: Avoid implicit rename if involved as source on other side' '
	test_create_repo 3a &&
	(
		cd 3a &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		echo d >z/d &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		test_tick &&
		git commit --allow-empty -m "A" &&

		git checkout B &&
		mkdir y &&
		mkdir x &&
		git mv z/b y/ &&
		git mv z/c y/ &&
		git mv z/d x/ &&
		rmdir z &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '3a-check: Avoid implicit rename if involved as source on other side' '
	(
		cd 3a &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 3 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:x/d &&
		git rev-parse >expect \
			O:z/b    O:z/c    O:z/d &&
		test_cmp expect actual
	)
'

# Testcase 3b, Avoid implicit rename if involved as source on other side
#   (Related to testcases 5c and 7c, also kind of 1e and 1f)
#   Commit O: z/{b,c,d}
#   Commit A: y/{b,c}, x/d
#   Commit B: z/{b,c}, w/d
#   Expected: y/{b,c}, CONFLICT:(z/d -> x/d vs. w/d)
#   NOTE: We're particularly checking that since z/d is already involved as
#         a source in a file rename on the same side of history, that we don't
#         get it involved in directory rename detection.  If it were, we might
#         end up with CONFLICT:(z/d -> y/d vs. x/d vs. w/d), i.e. a
#         rename/rename/rename(1to3) conflict, which is just weird.
test_expect_success '3b-setup: Avoid implicit rename if involved as source on current side' '
	test_create_repo 3b &&
	(
		cd 3b &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		echo d >z/d &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		mkdir y &&
		mkdir x &&
		git mv z/b y/ &&
		git mv z/c y/ &&
		git mv z/d x/ &&
		rmdir z &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		mkdir w &&
		git mv z/d w/ &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '3b-check: Avoid implicit rename if involved as source on current side' '
	(
		cd 3b &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep CONFLICT.*rename/rename.*z/d.*x/d.*w/d out &&
		test_i18ngrep ! CONFLICT.*rename/rename.*y/d out &&

		git ls-files -s >out &&
		test_line_count = 5 out &&
		git ls-files -u >out &&
		test_line_count = 3 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			:0:y/b :0:y/c :1:z/d :2:x/d :3:w/d &&
		git rev-parse >expect \
			 O:z/b  O:z/c  O:z/d  O:z/d  O:z/d &&
		test_cmp expect actual &&

		test_path_is_missing z/d &&
		git hash-object >actual \
			x/d   w/d &&
		git rev-parse >expect \
			O:z/d O:z/d &&
		test_cmp expect actual
	)
'

###########################################################################
# Rules suggested by section 3:
#
#   Avoid directory-rename-detection for a path, if that path is the source
#   of a rename on either side of a merge.
###########################################################################


###########################################################################
# SECTION 4: Partially renamed directory; still exists on both sides of merge
#
# What if we were to attempt to do directory rename detection when someone
# "mostly" moved a directory but still left some files around, or,
# equivalently, fully renamed a directory in one commmit and then recreated
# that directory in a later commit adding some new files and then tried to
# merge?
#
# It's hard to divine user intent in these cases, because you can make an
# argument that, depending on the intermediate history of the side being
# merged, that some users will want files in that directory to
# automatically be detected and renamed, while users with a different
# intermediate history wouldn't want that rename to happen.
#
# I think that it is best to simply not have directory rename detection
# apply to such cases.  My reasoning for this is four-fold: (1) it's
# easiest for users in general to figure out what happened if we don't
# apply directory rename detection in any such case, (2) it's an easy rule
# to explain ["We don't do directory rename detection if the directory
# still exists on both sides of the merge"], (3) we can get some hairy
# edge/corner cases that would be really confusing and possibly not even
# representable in the index if we were to even try, and [related to 3] (4)
# attempting to resolve this issue of divining user intent by examining
# intermediate history goes against the spirit of three-way merges and is a
# path towards crazy corner cases that are far more complex than what we're
# already dealing with.
#
# Note that the wording of the rule ("We don't do directory rename
# detection if the directory still exists on both sides of the merge.")
# also excludes "renaming" of a directory into a subdirectory of itself
# (e.g. /some/dir/* -> /some/dir/subdir/*).  It may be possible to carve
# out an exception for "renaming"-beneath-itself cases without opening
# weird edge/corner cases for other partial directory renames, but for now
# we are keeping the rule simple.
#
# This section contains a test for a partially-renamed-directory case.
###########################################################################

# Testcase 4a, Directory split, with original directory still present
#   (Related to testcase 1f)
#   Commit O: z/{b,c,d,e}
#   Commit A: y/{b,c,d}, z/e
#   Commit B: z/{b,c,d,e,f}
#   Expected: y/{b,c,d}, z/{e,f}
#   NOTE: Even though most files from z moved to y, we don't want f to follow.

test_expect_success '4a-setup: Directory split, with original directory still present' '
	test_create_repo 4a &&
	(
		cd 4a &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		echo d >z/d &&
		echo e >z/e &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		mkdir y &&
		git mv z/b y/ &&
		git mv z/c y/ &&
		git mv z/d y/ &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		echo f >z/f &&
		git add z/f &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '4a-check: Directory split, with original directory still present' '
	(
		cd 4a &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 5 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:z/e HEAD:z/f &&
		git rev-parse >expect \
			O:z/b    O:z/c    O:z/d    O:z/e    B:z/f &&
		test_cmp expect actual
	)
'

###########################################################################
# Rules suggested by section 4:
#
#   Directory-rename-detection should be turned off for any directories (as
#   a source for renames) that exist on both sides of the merge.  (The "as
#   a source for renames" clarification is due to cases like 1c where
#   the target directory exists on both sides and we do want the rename
#   detection.)  But, sadly, see testcase 8b.
###########################################################################


###########################################################################
# SECTION 5: Files/directories in the way of subset of to-be-renamed paths
#
# Implicitly renaming files due to a detected directory rename could run
# into problems if there are files or directories in the way of the paths
# we want to rename.  Explore such cases in this section.
###########################################################################

# Testcase 5a, Merge directories, other side adds files to original and target
#   Commit O: z/{b,c},       y/d
#   Commit A: z/{b,c,e_1,f}, y/{d,e_2}
#   Commit B: y/{b,c,d}
#   Expected: z/e_1, y/{b,c,d,e_2,f} + CONFLICT warning
#   NOTE: While directory rename detection is active here causing z/f to
#         become y/f, we did not apply this for z/e_1 because that would
#         give us an add/add conflict for y/e_1 vs y/e_2.  This problem with
#         this add/add, is that both versions of y/e are from the same side
#         of history, giving us no way to represent this conflict in the
#         index.

test_expect_success '5a-setup: Merge directories, other side adds files to original and target' '
	test_create_repo 5a &&
	(
		cd 5a &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		mkdir y &&
		echo d >y/d &&
		git add z y &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		echo e1 >z/e &&
		echo f >z/f &&
		echo e2 >y/e &&
		git add z/e z/f y/e &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		git mv z/b y/ &&
		git mv z/c y/ &&
		rmdir z &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '5a-check: Merge directories, other side adds files to original and target' '
	(
		cd 5a &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT.*implicit dir rename" out &&

		git ls-files -s >out &&
		test_line_count = 6 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			:0:y/b :0:y/c :0:y/d :0:y/e :0:z/e :0:y/f &&
		git rev-parse >expect \
			 O:z/b  O:z/c  O:y/d  A:y/e  A:z/e  A:z/f &&
		test_cmp expect actual
	)
'

# Testcase 5b, Rename/delete in order to get add/add/add conflict
#   (Related to testcase 8d; these may appear slightly inconsistent to users;
#    Also related to testcases 7d and 7e)
#   Commit O: z/{b,c,d_1}
#   Commit A: y/{b,c,d_2}
#   Commit B: z/{b,c,d_1,e}, y/d_3
#   Expected: y/{b,c,e}, CONFLICT(add/add: y/d_2 vs. y/d_3)
#   NOTE: If z/d_1 in commit B were to be involved in dir rename detection, as
#         we normaly would since z/ is being renamed to y/, then this would be
#         a rename/delete (z/d_1 -> y/d_1 vs. deleted) AND an add/add/add
#         conflict of y/d_1 vs. y/d_2 vs. y/d_3.  Add/add/add is not
#         representable in the index, so the existence of y/d_3 needs to
#         cause us to bail on directory rename detection for that path, falling
#         back to git behavior without the directory rename detection.

test_expect_success '5b-setup: Rename/delete in order to get add/add/add conflict' '
	test_create_repo 5b &&
	(
		cd 5b &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		echo d1 >z/d &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git rm z/d &&
		git mv z y &&
		echo d2 >y/d &&
		git add y/d &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		mkdir y &&
		echo d3 >y/d &&
		echo e >z/e &&
		git add y/d z/e &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '5b-check: Rename/delete in order to get add/add/add conflict' '
	(
		cd 5b &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT (add/add).* y/d" out &&

		git ls-files -s >out &&
		test_line_count = 5 out &&
		git ls-files -u >out &&
		test_line_count = 2 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			:0:y/b :0:y/c :0:y/e :2:y/d :3:y/d &&
		git rev-parse >expect \
			 O:z/b  O:z/c  B:z/e  A:y/d  B:y/d &&
		test_cmp expect actual &&

		test_must_fail git rev-parse :1:y/d &&
		test_path_is_file y/d
	)
'

# Testcase 5c, Transitive rename would cause rename/rename/rename/add/add/add
#   (Directory rename detection would result in transitive rename vs.
#    rename/rename(1to2) and turn it into a rename/rename(1to3).  Further,
#    rename paths conflict with separate adds on the other side)
#   (Related to testcases 3b and 7c)
#   Commit O: z/{b,c}, x/d_1
#   Commit A: y/{b,c,d_2}, w/d_1
#   Commit B: z/{b,c,d_1,e}, w/d_3, y/d_4
#   Expected: A mess, but only a rename/rename(1to2)/add/add mess.  Use the
#             presence of y/d_4 in B to avoid doing transitive rename of
#             x/d_1 -> z/d_1 -> y/d_1, so that the only paths we have at
#             y/d are y/d_2 and y/d_4.  We still do the move from z/e to y/e,
#             though, because it doesn't have anything in the way.

test_expect_success '5c-setup: Transitive rename would cause rename/rename/rename/add/add/add' '
	test_create_repo 5c &&
	(
		cd 5c &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		mkdir x &&
		echo d1 >x/d &&
		git add z x &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git mv z y &&
		echo d2 >y/d &&
		git add y/d &&
		git mv x w &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		git mv x/d z/ &&
		mkdir w &&
		mkdir y &&
		echo d3 >w/d &&
		echo d4 >y/d &&
		echo e >z/e &&
		git add w/ y/ z/e &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '5c-check: Transitive rename would cause rename/rename/rename/add/add/add' '
	(
		cd 5c &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*z/d" out &&
		test_i18ngrep "CONFLICT (add/add).* y/d" out &&

		git ls-files -s >out &&
		test_line_count = 9 out &&
		git ls-files -u >out &&
		test_line_count = 6 out &&
		git ls-files -o >out &&
		test_line_count = 3 out &&

		git rev-parse >actual \
			:0:y/b :0:y/c :0:y/e &&
		git rev-parse >expect \
			 O:z/b  O:z/c  B:z/e &&
		test_cmp expect actual &&

		test_must_fail git rev-parse :1:y/d &&
		git rev-parse >actual \
			:2:w/d :3:w/d :1:x/d :2:y/d :3:y/d :3:z/d &&
		git rev-parse >expect \
			 O:x/d  B:w/d  O:x/d  A:y/d  B:y/d  O:x/d &&
		test_cmp expect actual &&

		git hash-object >actual \
			w/d~HEAD w/d~B^0 z/d &&
		git rev-parse >expect \
			O:x/d    B:w/d   O:x/d &&
		test_cmp expect actual &&
		test_path_is_missing x/d &&
		test_path_is_file y/d &&
		grep -q "<<<<" y/d  # conflict markers should be present
	)
'

# Testcase 5d, Directory/file/file conflict due to directory rename
#   Commit O: z/{b,c}
#   Commit A: y/{b,c,d_1}
#   Commit B: z/{b,c,d_2,f}, y/d/e
#   Expected: y/{b,c,d/e,f}, z/d_2, CONFLICT(file/directory), y/d_1~HEAD
#   Note: The fact that y/d/ exists in B makes us bail on directory rename
#         detection for z/d_2, but that doesn't prevent us from applying the
#         directory rename detection for z/f -> y/f.

test_expect_success '5d-setup: Directory/file/file conflict due to directory rename' '
	test_create_repo 5d &&
	(
		cd 5d &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git mv z y &&
		echo d1 >y/d &&
		git add y/d &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		mkdir -p y/d &&
		echo e >y/d/e &&
		echo d2 >z/d &&
		echo f >z/f &&
		git add y/d/e z/d z/f &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_failure '5d-check: Directory/file/file conflict due to directory rename' '
	(
		cd 5d &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT (file/directory).*y/d" out &&

		git ls-files -s >out &&
		test_line_count = 6 out &&
		git ls-files -u >out &&
		test_line_count = 1 out &&
		git ls-files -o >out &&
		test_line_count = 2 out &&

		git rev-parse >actual \
			:0:y/b :0:y/c :0:z/d :0:y/f :2:y/d :0:y/d/e &&
		git rev-parse >expect \
			 O:z/b  O:z/c  B:z/d  B:z/f  A:y/d  B:y/d/e &&
		test_cmp expect actual &&

		git hash-object y/d~HEAD >actual &&
		git rev-parse A:y/d >expect &&
		test_cmp expect actual
	)
'

###########################################################################
# Rules suggested by section 5:
#
#   If a subset of to-be-renamed files have a file or directory in the way,
#   "turn off" the directory rename for those specific sub-paths, falling
#   back to old handling.  But, sadly, see testcases 8a and 8b.
###########################################################################


###########################################################################
# SECTION 6: Same side of the merge was the one that did the rename
#
# It may sound obvious that you only want to apply implicit directory
# renames to directories if the _other_ side of history did the renaming.
# If you did make an implementation that didn't explicitly enforce this
# rule, the majority of cases that would fall under this section would
# also be solved by following the rules from the above sections.  But
# there are still a few that stick out, so this section covers them just
# to make sure we also get them right.
###########################################################################

# Testcase 6a, Tricky rename/delete
#   Commit O: z/{b,c,d}
#   Commit A: z/b
#   Commit B: y/{b,c}, z/d
#   Expected: y/b, CONFLICT(rename/delete, z/c -> y/c vs. NULL)
#   Note: We're just checking here that the rename of z/b and z/c to put
#         them under y/ doesn't accidentally catch z/d and make it look like
#         it is also involved in a rename/delete conflict.

test_expect_success '6a-setup: Tricky rename/delete' '
	test_create_repo 6a &&
	(
		cd 6a &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		echo d >z/d &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git rm z/c &&
		git rm z/d &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		mkdir y &&
		git mv z/b y/ &&
		git mv z/c y/ &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '6a-check: Tricky rename/delete' '
	(
		cd 6a &&

		git checkout A^0 &&

		test_must_fail git merge -s recursive B^0 >out &&
		test_i18ngrep "CONFLICT (rename/delete).*z/c.*y/c" out &&

		git ls-files -s >out &&
		test_line_count = 2 out &&
		git ls-files -u >out &&
		test_line_count = 1 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			:0:y/b :3:y/c &&
		git rev-parse >expect \
			 O:z/b  O:z/c &&
		test_cmp expect actual
	)
'

# Testcase 6b, Same rename done on both sides
#   (Related to testcases 6c and 8e)
#   Commit O: z/{b,c}
#   Commit A: y/{b,c}
#   Commit B: y/{b,c}, z/d
#   Expected: y/{b,c}, z/d
#   Note: If we did directory rename detection here, we'd move z/d into y/,
#         but B did that rename and still decided to put the file into z/,
#         so we probably shouldn't apply directory rename detection for it.

test_expect_success '6b-setup: Same rename done on both sides' '
	test_create_repo 6b &&
	(
		cd 6b &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		git mv z y &&
		test_tick &&
		git commit -m "A" &&

		git checkout B &&
		git mv z y &&
		mkdir z &&
		echo d >z/d &&
		git add z/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '6b-check: Same rename done on both sides' '
	(
		cd 6b &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 3 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:z/d &&
		git rev-parse >expect \
			O:z/b    O:z/c    B:z/d &&
		test_cmp expect actual
	)
'

# Testcase 6c, Rename only done on same side
#   (Related to testcases 6b and 8e)
#   Commit O: z/{b,c}
#   Commit A: z/{b,c} (no change)
#   Commit B: y/{b,c}, z/d
#   Expected: y/{b,c}, z/d
#   NOTE: Seems obvious, but just checking that the implementation doesn't
#         "accidentally detect a rename" and give us y/{b,c,d}.

test_expect_success '6c-setup: Rename only done on same side' '
	test_create_repo 6c &&
	(
		cd 6c &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		test_tick &&
		git commit --allow-empty -m "A" &&

		git checkout B &&
		git mv z y &&
		mkdir z &&
		echo d >z/d &&
		git add z/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '6c-check: Rename only done on same side' '
	(
		cd 6c &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 3 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:z/d &&
		git rev-parse >expect \
			O:z/b    O:z/c    B:z/d &&
		test_cmp expect actual
	)
'

# Testcase 6d, We don't always want transitive renaming
#   (Related to testcase 1c)
#   Commit O: z/{b,c}, x/d
#   Commit A: z/{b,c}, x/d (no change)
#   Commit B: y/{b,c}, z/d
#   Expected: y/{b,c}, z/d
#   NOTE: Again, this seems obvious but just checking that the implementation
#         doesn't "accidentally detect a rename" and give us y/{b,c,d}.

test_expect_success '6d-setup: We do not always want transitive renaming' '
	test_create_repo 6d &&
	(
		cd 6d &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		mkdir x &&
		echo d >x/d &&
		git add z x &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		test_tick &&
		git commit --allow-empty -m "A" &&

		git checkout B &&
		git mv z y &&
		git mv x z &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '6d-check: We do not always want transitive renaming' '
	(
		cd 6d &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 3 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:z/d &&
		git rev-parse >expect \
			O:z/b    O:z/c    O:x/d &&
		test_cmp expect actual
	)
'

# Testcase 6e, Add/add from one-side
#   Commit O: z/{b,c}
#   Commit A: z/{b,c} (no change)
#   Commit B: y/{b,c,d_1}, z/d_2
#   Expected: y/{b,c,d_1}, z/d_2
#   NOTE: Again, this seems obvious but just checking that the implementation
#         doesn't "accidentally detect a rename" and give us y/{b,c} +
#         add/add conflict on y/d_1 vs y/d_2.

test_expect_success '6e-setup: Add/add from one side' '
	test_create_repo 6e &&
	(
		cd 6e &&

		mkdir z &&
		echo b >z/b &&
		echo c >z/c &&
		git add z &&
		test_tick &&
		git commit -m "O" &&

		git branch O &&
		git branch A &&
		git branch B &&

		git checkout A &&
		test_tick &&
		git commit --allow-empty -m "A" &&

		git checkout B &&
		git mv z y &&
		echo d1 > y/d &&
		mkdir z &&
		echo d2 > z/d &&
		git add y/d z/d &&
		test_tick &&
		git commit -m "B"
	)
'

test_expect_success '6e-check: Add/add from one side' '
	(
		cd 6e &&

		git checkout A^0 &&

		git merge -s recursive B^0 &&

		git ls-files -s >out &&
		test_line_count = 4 out &&
		git ls-files -u >out &&
		test_line_count = 0 out &&
		git ls-files -o >out &&
		test_line_count = 1 out &&

		git rev-parse >actual \
			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:z/d &&
		git rev-parse >expect \
			O:z/b    O:z/c    B:y/d    B:z/d &&
		test_cmp expect actual
	)
'

###########################################################################
# Rules suggested by section 6:
#
#   Only apply implicit directory renames to directories if the other
#   side of history is the one doing the renaming.
###########################################################################

test_done