git-commit-vandalism/t/t6043-merge-rename-directories.sh
Elijah Newren 881e48bafd directory rename detection: partially renamed directory testcase/discussion
Add a long note about why we are not considering "partial directory
renames" for the current directory rename detection implementation.

Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-14 13:02:51 -08:00

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#!/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.
###########################################################################
test_done