)
'
+# SORRY FOR THE SUPER LONG DESCRIPTION, BUT THIS NEXT ONE IS HAIRY
#
# criss-cross + d/f conflict via add/add:
# Commit A: Neither file 'a' nor directory 'a/' exists.
# Commit B: Introduce 'a'
# Commit C: Introduce 'a/file'
-# Commit D: Merge B & C, keeping 'a' and deleting 'a/'
-#
-# Two different later cases:
+# Commit D1: Merge B & C, keeping 'a' and deleting 'a/'
# Commit E1: Merge B & C, deleting 'a' but keeping 'a/file'
-# Commit E2: Merge B & C, deleting 'a' but keeping a slightly modified 'a/file'
#
-# B D
+# B D1 or D2
# o---o
# / \ / \
# A o X ? F
# \ / \ /
# o---o
-# C E1 or E2
-#
-# Merging D & E1 requires we first create a virtual merge base X from
-# merging A & B in memory. Now, if X could keep both 'a' and 'a/file' in
-# the index, then the merge of D & E1 could be resolved cleanly with both
-# 'a' and 'a/file' removed. Since git does not currently allow creating
-# such a tree, the best we can do is have X contain both 'a~<unique>' and
-# 'a/file' resulting in the merge of D and E1 having a rename/delete
-# conflict for 'a'. (Although this merge appears to be unsolvable with git
-# currently, git could do a lot better than it currently does with these
-# d/f conflicts, which is the purpose of this test.)
-#
-# Merge of D & E2 has similar issues for path 'a', but should always result
-# in a modify/delete conflict for path 'a/file'.
-#
-# We run each merge in both directions, to check for directional issues
-# with D/F conflict handling.
+# C E1 or E2 or E3
+#
+# I'll describe D2, E2, & E3 (which are alternatives for D1 & E1) more below...
+#
+# Merging D1 & E1 requires we first create a virtual merge base X from
+# merging A & B in memory. There are several possibilities for the merge-base:
+# 1: Keep both 'a' and 'a/file' (assuming crazy filesystem allowing a tree
+# with a directory and file at same path): results in merge of D1 & E1
+# being clean with both files deleted. Bad (no conflict detected).
+# 2: Keep 'a' but not 'a/file': Merging D1 & E1 is clean and matches E1. Bad.
+# 3: Keep 'a/file' but not 'a': Merging D1 & E1 is clean and matches D1. Bad.
+# 4: Keep neither file: Merging D1 & E1 reports the D/F add/add conflict.
+#
+# So 4 sounds good for this case, but if we were to merge D1 & E3, where E3
+# is defined as:
+# Commit E3: Merge B & C, keeping modified a, and deleting a/
+# then we'd get an add/add conflict for 'a', which seems suboptimal. A little
+# creativity leads us to an alternate choice:
+# 5: Keep 'a' as 'a~$UNIQUE' and a/file; results:
+# Merge D1 & E1: rename/delete conflict for 'a'; a/file silently deleted
+# Merge D1 & E3 is clean, as expected.
+#
+# So choice 5 at least provides some kind of conflict for the original case,
+# and can merge cleanly as expected with D1 and E3. It also made things just
+# slightly funny for merging D1 and e$, where E4 is defined as:
+# Commit E4: Merge B & C, modifying 'a' and renaming to 'a2', and deleting 'a/'
+# in this case, we'll get a rename/rename(1to2) conflict because a~$UNIQUE
+# gets renamed to 'a' in D1 and to 'a2' in E4. But that's better than having
+# two files (both 'a' and 'a2') sitting around without the user being notified
+# that we could detect they were related and need to be merged. Also, choice
+# 5 makes the handling of 'a/file' seem suboptimal. What if we were to merge
+# D2 and E4, where D2 is:
+# Commit D2: Merge B & C, renaming 'a'->'a2', keeping 'a/file'
+# This would result in a clean merge with 'a2' having three-way merged
+# contents (good), and deleting 'a/' (bad) -- it doesn't detect the
+# conflict in how the different sides treated a/file differently.
+# Continuing down the creative route:
+# 6: Keep 'a' as 'a~$UNIQUE1' and keep 'a/' as 'a~$UNIQUE2/'; results:
+# Merge D1 & E1: rename/delete conflict for 'a' and each path under 'a/'.
+# Merge D1 & E3: clean, as expected.
+# Merge D1 & E4: rename/rename(1to2) conflict on 'a' vs 'a2'.
+# Merge D2 & E4: clean for 'a2', rename/delete for a/file
+#
+# Choice 6 could cause rename detection to take longer (providing more targets
+# that need to be searched). Also, the conflict message for each path under
+# 'a/' might be annoying unless we can detect it at the directory level, print
+# it once, and then suppress it for individual filepaths underneath.
+#
+#
+# As of time of writing, git uses choice 5. Directory rename detection and
+# rename detection performance improvements might make choice 6 a desirable
+# improvement. But we can at least document where we fall short for now...
+#
+#
+# Historically, this testcase also used:
+# Commit E2: Merge B & C, deleting 'a' but keeping slightly modified 'a/file'
+# The merge of D1 & E2 is very similar to D1 & E1 -- it has similar issues for
+# path 'a', but should always result in a modify/delete conflict for path
+# 'a/file'. These tests ran the two merges
+# D1 & E1
+# D1 & E2
+# in both directions, to check for directional issues with D/F conflict
+# handling. Later we added
+# D1 & E3
+# D1 & E4
+# D2 & E4
+# for good measure, though we only ran those one way because we had pretty
+# good confidence in merge-recursive's directional handling of D/F issues.
+#
+# Just to summarize all the intermediate merge commits:
+# Commit D1: Merge B & C, keeping a and deleting a/
+# Commit D2: Merge B & C, renaming a->a2, keeping a/file
+# Commit E1: Merge B & C, deleting a but keeping a/file
+# Commit E2: Merge B & C, deleting a but keeping slightly modified a/file
+# Commit E3: Merge B & C, keeping modified a, and deleting a/
+# Commit E4: Merge B & C, modifying 'a' and renaming to 'a2', and deleting 'a/'
#
test_expect_success 'setup differently handled merges of directory/file conflict' '
git branch B &&
git checkout -b C &&
mkdir a &&
- echo 10 >a/file &&
+ test_write_lines a b c d e f g >a/file &&
git add a/file &&
test_tick &&
git commit -m C &&
git checkout B &&
- echo 5 >a &&
+ test_write_lines 1 2 3 4 5 6 7 >a &&
git add a &&
test_tick &&
git commit -m B &&
git checkout B^0 &&
- test_must_fail git merge C &&
- git clean -f &&
- rm -rf a/ &&
- echo 5 >a &&
- git add a &&
- test_tick &&
- git commit -m D &&
- git tag D &&
+ git merge -s ours -m D1 C^0 &&
+ git tag D1 &&
+
+ git checkout B^0 &&
+ test_must_fail git merge C^0 &&
+ git clean -fd &&
+ git rm -rf a/ &&
+ git rm a &&
+ git cat-file -p B:a >a2 &&
+ git add a2 &&
+ git commit -m D2 &&
+ git tag D2 &&
git checkout C^0 &&
- test_must_fail git merge B &&
- git clean -f &&
- git rm --cached a &&
- echo 10 >a/file &&
- git add a/file &&
- test_tick &&
- git commit -m E1 &&
+ git merge -s ours -m E1 B^0 &&
git tag E1 &&
git checkout C^0 &&
- test_must_fail git merge B &&
- git clean -f &&
- git rm --cached a &&
- printf "10\n11\n" >a/file &&
+ git merge -s ours -m E2 B^0 &&
+ test_write_lines a b c d e f g h >a/file &&
git add a/file &&
- test_tick &&
- git commit -m E2 &&
- git tag E2
+ git commit --amend -C HEAD &&
+ git tag E2 &&
+
+ git checkout C^0 &&
+ test_must_fail git merge B^0 &&
+ git clean -fd &&
+ git rm -rf a/ &&
+ test_write_lines 1 2 3 4 5 6 7 8 >a &&
+ git add a &&
+ git commit -m E3 &&
+ git tag E3
+
+ git checkout C^0 &&
+ test_must_fail git merge B^0 &&
+ git clean -fd &&
+ git rm -rf a/ &&
+ git rm a &&
+ test_write_lines 1 2 3 4 5 6 7 8 >a2 &&
+ git add a2 &&
+ git commit -m E4 &&
+ git tag E4
)
'
-test_expect_success 'merge of D & E1 fails but has appropriate contents' '
+test_expect_success 'merge of D1 & E1 fails but has appropriate contents' '
test_when_finished "git -C directory-file reset --hard" &&
test_when_finished "git -C directory-file clean -fdqx" &&
(
cd directory-file &&
- git checkout D^0 &&
+ git checkout D1^0 &&
test_must_fail git merge -s recursive E1^0 &&
)
'
-test_expect_success 'merge of E1 & D fails but has appropriate contents' '
+test_expect_success 'merge of E1 & D1 fails but has appropriate contents' '
test_when_finished "git -C directory-file reset --hard" &&
test_when_finished "git -C directory-file clean -fdqx" &&
(
git checkout E1^0 &&
- test_must_fail git merge -s recursive D^0 &&
+ test_must_fail git merge -s recursive D1^0 &&
git ls-files -s >out &&
test_line_count = 2 out &&
)
'
-test_expect_success 'merge of D & E2 fails but has appropriate contents' '
+test_expect_success 'merge of D1 & E2 fails but has appropriate contents' '
test_when_finished "git -C directory-file reset --hard" &&
test_when_finished "git -C directory-file clean -fdqx" &&
(
cd directory-file &&
- git checkout D^0 &&
+ git checkout D1^0 &&
test_must_fail git merge -s recursive E2^0 &&
)
'
-test_expect_success 'merge of E2 & D fails but has appropriate contents' '
+test_expect_success 'merge of E2 & D1 fails but has appropriate contents' '
test_when_finished "git -C directory-file reset --hard" &&
test_when_finished "git -C directory-file clean -fdqx" &&
(
git checkout E2^0 &&
- test_must_fail git merge -s recursive D^0 &&
+ test_must_fail git merge -s recursive D1^0 &&
git ls-files -s >out &&
test_line_count = 4 out &&
:3:a :2:a/file :1:a/file :0:ignore-me &&
test_cmp expect actual
- test_path_is_file a~D^0
+ test_path_is_file a~D1^0
+ )
+'
+
+test_expect_success 'merge of D1 & E3 succeeds' '
+ test_when_finished "git -C directory-file reset --hard" &&
+ test_when_finished "git -C directory-file clean -fdqx" &&
+ (
+ cd directory-file &&
+
+ git checkout D1^0 &&
+
+ git merge -s recursive E3^0 &&
+
+ git ls-files -s >out &&
+ test_line_count = 2 out &&
+ git ls-files -u >out &&
+ test_line_count = 0 out &&
+ git ls-files -o >out &&
+ test_line_count = 1 out &&
+
+ git rev-parse >expect \
+ A:ignore-me E3:a &&
+ git rev-parse >actual \
+ :0:ignore-me :0:a &&
+ test_cmp expect actual
+ )
+'
+
+test_expect_success 'merge of D1 & E4 notifies user a and a2 are related' '
+ test_when_finished "git -C directory-file reset --hard" &&
+ test_when_finished "git -C directory-file clean -fdqx" &&
+ (
+ cd directory-file &&
+
+ git checkout D1^0 &&
+
+ test_must_fail git merge -s recursive E4^0 &&
+
+ git ls-files -s >out &&
+ test_line_count = 4 out &&
+ git ls-files -u >out &&
+ test_line_count = 3 out &&
+ git ls-files -o >out &&
+ test_line_count = 1 out &&
+
+ git rev-parse >expect \
+ A:ignore-me B:a D1:a E4:a2 &&
+ git rev-parse >actual \
+ :0:ignore-me :1:a~Temporary\ merge\ branch\ 2 :2:a :3:a2 &&
+ test_cmp expect actual
+ )
+'
+
+test_expect_failure 'merge of D2 & E4 merges a2s & reports conflict for a/file' '
+ test_when_finished "git -C directory-file reset --hard" &&
+ test_when_finished "git -C directory-file clean -fdqx" &&
+ (
+ cd directory-file &&
+
+ git checkout D2^0 &&
+
+ test_must_fail git merge -s recursive E4^0 &&
+
+ git ls-files -s >out &&
+ test_line_count = 3 out &&
+ git ls-files -u >out &&
+ test_line_count = 1 out &&
+ git ls-files -o >out &&
+ test_line_count = 1 out &&
+
+ git rev-parse >expect \
+ A:ignore-me E4:a2 D2:a/file &&
+ git rev-parse >actual \
+ :0:ignore-me :0:a2 :2:a/file &&
+ test_cmp expect actual
)
'
projects / thirdparty / git.git / blobdiff