# 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