Merge branch 'en/merge-recursive'

* en/merge-recursive: (41 commits)
  t6022: Use -eq not = to test output of wc -l
  merge-recursive:make_room_for_directories - work around dumb compilers
  merge-recursive: Remove redundant path clearing for D/F conflicts
  merge-recursive: Make room for directories in D/F conflicts
  handle_delete_modify(): Check whether D/F conflicts are still present
  merge_content(): Check whether D/F conflicts are still present
  conflict_rename_rename_1to2(): Fix checks for presence of D/F conflicts
  conflict_rename_delete(): Check whether D/F conflicts are still present
  merge-recursive: Delay modify/delete conflicts if D/F conflict present
  merge-recursive: Delay content merging for renames
  merge-recursive: Delay handling of rename/delete conflicts
  merge-recursive: Move handling of double rename of one file to other file
  merge-recursive: Move handling of double rename of one file to two
  merge-recursive: Avoid doubly merging rename/add conflict contents
  merge-recursive: Update merge_content() call signature
  merge-recursive: Update conflict_rename_rename_1to2() call signature
  merge-recursive: Structure process_df_entry() to handle more cases
  merge-recursive: Have process_entry() skip D/F or rename entries
  merge-recursive: New function to assist resolving renames in-core only
  merge-recursive: New data structures for deferring of D/F conflicts
  ...

Conflicts:
	t/t6020-merge-df.sh
	t/t6036-recursive-corner-cases.sh

6 files changed, 743 insertions, 17 deletions

diff --git a/t/t3030-merge-recursive.sh b/t/t3030-merge-recursive.sh
index 20d4f11dbe..34794f8a70 100755
--- a/t/t3030-merge-recursive.sh
+++ b/t/t3030-merge-recursive.sh
@@ -25,6 +25,10 @@ test_expect_success 'setup 1' '
 	git branch submod &&
 	git branch copy &&
 	git branch rename &&
+	if test_have_prereq SYMLINKS
+	then
+		git branch rename-ln
+	fi &&
 
 	echo hello >>a &&
 	cp a d/e &&
@@ -255,7 +259,16 @@ test_expect_success 'setup 8' '
 	git mv a e &&
 	git add e &&
 	test_tick &&
-	git commit -m "rename a->e"
+	git commit -m "rename a->e" &&
+	if test_have_prereq SYMLINKS
+	then
+		git checkout rename-ln &&
+		git mv a e &&
+		ln -s e a &&
+		git add a e &&
+		test_tick &&
+		git commit -m "rename a->e, symlink a->e"
+	fi
 '
 
 test_expect_success 'setup 9' '
@@ -615,4 +628,26 @@ test_expect_success 'merge-recursive copy vs. rename' '
 	test_cmp expected actual
 '
 
+if test_have_prereq SYMLINKS
+then
+	test_expect_success 'merge-recursive rename vs. rename/symlink' '
+
+		git checkout -f rename &&
+		git merge rename-ln &&
+		( git ls-tree -r HEAD ; git ls-files -s ) >actual &&
+		(
+			echo "100644 blob $o0	b"
+			echo "100644 blob $o0	c"
+			echo "100644 blob $o0	d/e"
+			echo "100644 blob $o0	e"
+			echo "100644 $o0 0	b"
+			echo "100644 $o0 0	c"
+			echo "100644 $o0 0	d/e"
+			echo "100644 $o0 0	e"
+		) >expected &&
+		test_cmp expected actual
+	'
+fi
+
+
 test_done
diff --git a/t/t3509-cherry-pick-merge-df.sh b/t/t3509-cherry-pick-merge-df.sh
index a5ccdbf8fc..948ca1bce6 100755
--- a/t/t3509-cherry-pick-merge-df.sh
+++ b/t/t3509-cherry-pick-merge-df.sh
@@ -32,4 +32,70 @@ test_expect_success SYMLINKS 'Cherry-pick succeeds with rename across D/F confli
 	git cherry-pick branch
 '
 
+test_expect_success 'Setup rename with file on one side matching directory name on other' '
+	git checkout --orphan nick-testcase &&
+	git rm -rf . &&
+
+	>empty &&
+	git add empty &&
+	git commit -m "Empty file" &&
+
+	git checkout -b simple &&
+	mv empty file &&
+	mkdir empty &&
+	mv file empty &&
+	git add empty/file &&
+	git commit -m "Empty file under empty dir" &&
+
+	echo content >newfile &&
+	git add newfile &&
+	git commit -m "New file"
+'
+
+test_expect_success 'Cherry-pick succeeds with was_a_dir/file -> was_a_dir (resolve)' '
+	git reset --hard &&
+	git checkout -q nick-testcase^0 &&
+	git cherry-pick --strategy=resolve simple
+'
+
+test_expect_success 'Cherry-pick succeeds with was_a_dir/file -> was_a_dir (recursive)' '
+	git reset --hard &&
+	git checkout -q nick-testcase^0 &&
+	git cherry-pick --strategy=recursive simple
+'
+
+test_expect_success 'Setup rename with file on one side matching different dirname on other' '
+	git reset --hard &&
+	git checkout --orphan mergeme &&
+	git rm -rf . &&
+
+	mkdir sub &&
+	mkdir othersub &&
+	echo content > sub/file &&
+	echo foo > othersub/whatever &&
+	git add -A &&
+	git commit -m "Common commmit" &&
+
+	git rm -rf othersub &&
+	git mv sub/file othersub &&
+	git commit -m "Commit to merge" &&
+
+	git checkout -b newhead mergeme~1 &&
+	>independent-change &&
+	git add independent-change &&
+	git commit -m "Completely unrelated change"
+'
+
+test_expect_success 'Cherry-pick with rename to different D/F conflict succeeds (resolve)' '
+	git reset --hard &&
+	git checkout -q newhead^0 &&
+	git cherry-pick --strategy=resolve mergeme
+'
+
+test_expect_success 'Cherry-pick with rename to different D/F conflict succeeds (recursive)' '
+	git reset --hard &&
+	git checkout -q newhead^0 &&
+	git cherry-pick --strategy=recursive mergeme
+'
+
 test_done
diff --git a/t/t6020-merge-df.sh b/t/t6020-merge-df.sh
index 5d91d056d2..eec8f4e3ed 100755
--- a/t/t6020-merge-df.sh
+++ b/t/t6020-merge-df.sh
@@ -6,19 +6,22 @@
 test_description='Test merge with directory/file conflicts'
 . ./test-lib.sh
 
-test_expect_success 'prepare repository' \
-'echo "Hello" > init &&
-git add init &&
-git commit -m "Initial commit" &&
-git branch B &&
-mkdir dir &&
-echo "foo" > dir/foo &&
-git add dir/foo &&
-git commit -m "File: dir/foo" &&
-git checkout B &&
-echo "file dir" > dir &&
-git add dir &&
-git commit -m "File: dir"'
+test_expect_success 'prepare repository' '
+	echo Hello >init &&
+	git add init &&
+	git commit -m initial &&
+
+	git branch B &&
+	mkdir dir &&
+	echo foo >dir/foo &&
+	git add dir/foo &&
+	git commit -m "File: dir/foo" &&
+
+	git checkout B &&
+	echo file dir >dir &&
+	git add dir &&
+	git commit -m "File: dir"
+'
 
 test_expect_success 'Merge with d/f conflicts' '
 	test_expect_code 1 git merge "merge msg" B master
@@ -47,4 +50,51 @@ test_expect_success 'F/D conflict' '
 	git merge master
 '
 
+test_expect_success 'setup modify/delete + directory/file conflict' '
+	git checkout --orphan modify &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	printf "a\nb\nc\nd\ne\nf\ng\nh\n" >letters &&
+	git add letters &&
+	git commit -m initial &&
+
+	echo i >>letters &&
+	git add letters &&
+	git commit -m modified &&
+
+	git checkout -b delete HEAD^ &&
+	git rm letters &&
+	mkdir letters &&
+	>letters/file &&
+	git add letters &&
+	git commit -m deleted
+'
+
+test_expect_success 'modify/delete + directory/file conflict' '
+	git checkout delete^0 &&
+	test_must_fail git merge modify &&
+
+	test 3 = $(git ls-files -s | wc -l) &&
+	test 2 = $(git ls-files -u | wc -l) &&
+	test 1 = $(git ls-files -o | wc -l) &&
+
+	test -f letters/file &&
+	test -f letters~modify
+'
+
+test_expect_success 'modify/delete + directory/file conflict; other way' '
+	git reset --hard &&
+	git clean -f &&
+	git checkout modify^0 &&
+	test_must_fail git merge delete &&
+
+	test 3 = $(git ls-files -s | wc -l) &&
+	test 2 = $(git ls-files -u | wc -l) &&
+	test 1 = $(git ls-files -o | wc -l) &&
+
+	test -f letters/file &&
+	test -f letters~HEAD
+'
+
 test_done
diff --git a/t/t6022-merge-rename.sh b/t/t6022-merge-rename.sh
index 83efc7abf5..1ed259d864 100755
--- a/t/t6022-merge-rename.sh
+++ b/t/t6022-merge-rename.sh
@@ -3,6 +3,11 @@
 test_description='Merge-recursive merging renames'
 . ./test-lib.sh
 
+modify () {
+	sed -e "$1" <"$2" >"$2.x" &&
+	mv "$2.x" "$2"
+}
+
 test_expect_success setup \
 '
 cat >A <<\EOF &&
@@ -243,4 +248,365 @@ test_expect_success 'merge of identical changes in a renamed file' '
 	GIT_MERGE_VERBOSITY=3 git merge change+rename | grep "^Skipped B"
 '
 
+test_expect_success 'setup for rename + d/f conflicts' '
+	git reset --hard &&
+	git checkout --orphan dir-in-way &&
+	git rm -rf . &&
+
+	mkdir sub &&
+	mkdir dir &&
+	printf "1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n" >sub/file &&
+	echo foo >dir/file-in-the-way &&
+	git add -A &&
+	git commit -m "Common commmit" &&
+
+	echo 11 >>sub/file &&
+	echo more >>dir/file-in-the-way &&
+	git add -u &&
+	git commit -m "Commit to merge, with dir in the way" &&
+
+	git checkout -b dir-not-in-way &&
+	git reset --soft HEAD^ &&
+	git rm -rf dir &&
+	git commit -m "Commit to merge, with dir removed" -- dir sub/file &&
+
+	git checkout -b renamed-file-has-no-conflicts dir-in-way~1 &&
+	git rm -rf dir &&
+	git rm sub/file &&
+	printf "1\n2\n3\n4\n5555\n6\n7\n8\n9\n10\n" >dir &&
+	git add dir &&
+	git commit -m "Independent change" &&
+
+	git checkout -b renamed-file-has-conflicts dir-in-way~1 &&
+	git rm -rf dir &&
+	git mv sub/file dir &&
+	echo 12 >>dir &&
+	git add dir &&
+	git commit -m "Conflicting change"
+'
+
+printf "1\n2\n3\n4\n5555\n6\n7\n8\n9\n10\n11\n" >expected
+
+test_expect_success 'Rename+D/F conflict; renamed file merges + dir not in way' '
+	git reset --hard &&
+	git checkout -q renamed-file-has-no-conflicts^0 &&
+	git merge --strategy=recursive dir-not-in-way &&
+	git diff --quiet &&
+	test -f dir &&
+	test_cmp expected dir
+'
+
+test_expect_success 'Rename+D/F conflict; renamed file merges but dir in way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q renamed-file-has-no-conflicts^0 &&
+	test_must_fail git merge --strategy=recursive dir-in-way >output &&
+
+	grep "CONFLICT (delete/modify): dir/file-in-the-way" output &&
+	grep "Auto-merging dir" output &&
+	grep "Adding as dir~HEAD instead" output &&
+
+	test 2 -eq "$(git ls-files -u | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~HEAD &&
+	test_cmp expected dir~HEAD
+'
+
+test_expect_success 'Same as previous, but merged other way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q dir-in-way^0 &&
+	test_must_fail git merge --strategy=recursive renamed-file-has-no-conflicts >output 2>errors &&
+
+	! grep "error: refusing to lose untracked file at" errors &&
+	grep "CONFLICT (delete/modify): dir/file-in-the-way" output &&
+	grep "Auto-merging dir" output &&
+	grep "Adding as dir~renamed-file-has-no-conflicts instead" output &&
+
+	test 2 -eq "$(git ls-files -u | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~renamed-file-has-no-conflicts &&
+	test_cmp expected dir~renamed-file-has-no-conflicts
+'
+
+cat >expected <<\EOF &&
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+<<<<<<< HEAD
+12
+=======
+11
+>>>>>>> dir-not-in-way
+EOF
+
+test_expect_success 'Rename+D/F conflict; renamed file cannot merge, dir not in way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q renamed-file-has-conflicts^0 &&
+	test_must_fail git merge --strategy=recursive dir-not-in-way &&
+
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 3 -eq "$(git ls-files -u dir | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir &&
+	test_cmp expected dir
+'
+
+test_expect_success 'Rename+D/F conflict; renamed file cannot merge and dir in the way' '
+	modify s/dir-not-in-way/dir-in-way/ expected &&
+
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q renamed-file-has-conflicts^0 &&
+	test_must_fail git merge --strategy=recursive dir-in-way &&
+
+	test 5 -eq "$(git ls-files -u | wc -l)" &&
+	test 3 -eq "$(git ls-files -u dir | grep -v file-in-the-way | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~HEAD &&
+	test_cmp expected dir~HEAD
+'
+
+cat >expected <<\EOF &&
+1
+2
+3
+4
+5
+6
+7
+8
+9
+10
+<<<<<<< HEAD
+11
+=======
+12
+>>>>>>> renamed-file-has-conflicts
+EOF
+
+test_expect_success 'Same as previous, but merged other way' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q dir-in-way^0 &&
+	test_must_fail git merge --strategy=recursive renamed-file-has-conflicts &&
+
+	test 5 -eq "$(git ls-files -u | wc -l)" &&
+	test 3 -eq "$(git ls-files -u dir | grep -v file-in-the-way | wc -l)" &&
+	test 2 -eq "$(git ls-files -u dir/file-in-the-way | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+	test_must_fail git diff --cached --quiet &&
+
+	test -f dir/file-in-the-way &&
+	test -f dir~renamed-file-has-conflicts &&
+	test_cmp expected dir~renamed-file-has-conflicts
+'
+
+test_expect_success 'setup both rename source and destination involved in D/F conflict' '
+	git reset --hard &&
+	git checkout --orphan rename-dest &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	mkdir one &&
+	echo stuff >one/file &&
+	git add -A &&
+	git commit -m "Common commmit" &&
+
+	git mv one/file destdir &&
+	git commit -m "Renamed to destdir" &&
+
+	git checkout -b source-conflict HEAD~1 &&
+	git rm -rf one &&
+	mkdir destdir &&
+	touch one destdir/foo &&
+	git add -A &&
+	git commit -m "Conflicts in the way"
+'
+
+test_expect_success 'both rename source and destination involved in D/F conflict' '
+	git reset --hard &&
+	rm -rf dir~* &&
+	git checkout -q rename-dest^0 &&
+	test_must_fail git merge --strategy=recursive source-conflict &&
+
+	test 1 -eq "$(git ls-files -u | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+
+	test -f destdir/foo &&
+	test -f one &&
+	test -f destdir~HEAD &&
+	test "stuff" = "$(cat destdir~HEAD)"
+'
+
+test_expect_success 'setup pair rename to parent of other (D/F conflicts)' '
+	git reset --hard &&
+	git checkout --orphan rename-two &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	mkdir one &&
+	mkdir two &&
+	echo stuff >one/file &&
+	echo other >two/file &&
+	git add -A &&
+	git commit -m "Common commmit" &&
+
+	git rm -rf one &&
+	git mv two/file one &&
+	git commit -m "Rename two/file -> one" &&
+
+	git checkout -b rename-one HEAD~1 &&
+	git rm -rf two &&
+	git mv one/file two &&
+	rm -r one &&
+	git commit -m "Rename one/file -> two"
+'
+
+test_expect_success 'pair rename to parent of other (D/F conflicts) w/ untracked dir' '
+	git checkout -q rename-one^0 &&
+	mkdir one &&
+	test_must_fail git merge --strategy=recursive rename-two &&
+
+	test 2 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+
+	test 4 -eq $(find . | grep -v .git | wc -l) &&
+
+	test -d one &&
+	test -f one~rename-two &&
+	test -f two &&
+	test "other" = $(cat one~rename-two) &&
+	test "stuff" = $(cat two)
+'
+
+test_expect_success 'pair rename to parent of other (D/F conflicts) w/ clean start' '
+	git reset --hard &&
+	git clean -fdqx &&
+	test_must_fail git merge --strategy=recursive rename-two &&
+
+	test 2 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+
+	test_must_fail git diff --quiet &&
+
+	test 3 -eq $(find . | grep -v .git | wc -l) &&
+
+	test -f one &&
+	test -f two &&
+	test "other" = $(cat one) &&
+	test "stuff" = $(cat two)
+'
+
+test_expect_success 'setup rename of one file to two, with directories in the way' '
+	git reset --hard &&
+	git checkout --orphan first-rename &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	echo stuff >original &&
+	git add -A &&
+	git commit -m "Common commmit" &&
+
+	mkdir two &&
+	>two/file &&
+	git add two/file &&
+	git mv original one &&
+	git commit -m "Put two/file in the way, rename to one" &&
+
+	git checkout -b second-rename HEAD~1 &&
+	mkdir one &&
+	>one/file &&
+	git add one/file &&
+	git mv original two &&
+	git commit -m "Put one/file in the way, rename to two"
+'
+
+test_expect_success 'check handling of differently renamed file with D/F conflicts' '
+	git checkout -q first-rename^0 &&
+	test_must_fail git merge --strategy=recursive second-rename &&
+
+	test 5 -eq "$(git ls-files -s | wc -l)" &&
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+	test 1 -eq "$(git ls-files -u original | wc -l)" &&
+	test 2 -eq "$(git ls-files -o | wc -l)" &&
+
+	test -f one/file &&
+	test -f two/file &&
+	test -f one~HEAD &&
+	test -f two~second-rename &&
+	! test -f original
+'
+
+test_expect_success 'setup rename one file to two; directories moving out of the way' '
+	git reset --hard &&
+	git checkout --orphan first-rename-redo &&
+	git rm -rf . &&
+	git clean -fdqx &&
+
+	echo stuff >original &&
+	mkdir one two &&
+	touch one/file two/file &&
+	git add -A &&
+	git commit -m "Common commmit" &&
+
+	git rm -rf one &&
+	git mv original one &&
+	git commit -m "Rename to one" &&
+
+	git checkout -b second-rename-redo HEAD~1 &&
+	git rm -rf two &&
+	git mv original two &&
+	git commit -m "Rename to two"
+'
+
+test_expect_success 'check handling of differently renamed file with D/F conflicts' '
+	git checkout -q first-rename-redo^0 &&
+	test_must_fail git merge --strategy=recursive second-rename-redo &&
+
+	test 3 -eq "$(git ls-files -u | wc -l)" &&
+	test 1 -eq "$(git ls-files -u one | wc -l)" &&
+	test 1 -eq "$(git ls-files -u two | wc -l)" &&
+	test 1 -eq "$(git ls-files -u original | wc -l)" &&
+	test 0 -eq "$(git ls-files -o | wc -l)" &&
+
+	test -f one &&
+	test -f two &&
+	! test -f original
+'
+
 test_done
diff --git a/t/t6032-merge-large-rename.sh b/t/t6032-merge-large-rename.sh
index eac5ebac24..fdb6c25371 100755
--- a/t/t6032-merge-large-rename.sh
+++ b/t/t6032-merge-large-rename.sh
@@ -70,4 +70,34 @@ test_expect_success 'set merge.renamelimit to 5' '
 test_rename 5 ok
 test_rename 6 fail
 
+test_expect_success 'setup large simple rename' '
+	git config --unset merge.renamelimit &&
+	git config --unset diff.renamelimit &&
+
+	git reset --hard initial &&
+	for i in $(count 200); do
+		make_text foo bar baz >$i
+	done &&
+	git add . &&
+	git commit -m create-files &&
+
+	git branch simple-change &&
+	git checkout -b simple-rename &&
+
+	mkdir builtin &&
+	git mv [0-9]* builtin/ &&
+	git commit -m renamed &&
+
+	git checkout simple-change &&
+	>unrelated-change &&
+	git add unrelated-change &&
+	git commit -m unrelated-change
+'
+
+test_expect_success 'massive simple rename does not spam added files' '
+	unset GIT_MERGE_VERBOSITY &&
+	git merge --no-stat simple-rename | grep -v Removing >output &&
+	test 5 -gt "$(wc -l < output)"
+'
+
 test_done
diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6036-recursive-corner-cases.sh
index 004c365ad6..871577d90c 100755
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6036-recursive-corner-cases.sh
@@ -14,7 +14,7 @@ test_description='recursive merge corner cases'
 #  R1  R2
 #
 
-test_expect_success setup '
+test_expect_success 'setup basic criss-cross + rename with no modifications' '
 	ten="0 1 2 3 4 5 6 7 8 9" &&
 	for i in $ten
 	do
@@ -45,11 +45,190 @@ test_expect_success setup '
 	git tag R2
 '
 
-test_expect_success merge '
+test_expect_success 'merge simple rename+criss-cross with no modifications' '
 	git reset --hard &&
 	git checkout L2^0 &&
 
-	test_must_fail git merge -s recursive R2^0
+	test_must_fail git merge -s recursive R2^0 &&
+
+	test 5 = $(git ls-files -s | wc -l) &&
+	test 3 = $(git ls-files -u | wc -l) &&
+	test 0 = $(git ls-files -o | wc -l) &&
+
+	test $(git rev-parse :0:one) = $(git rev-parse L2:one) &&
+	test $(git rev-parse :0:two) = $(git rev-parse R2:two) &&
+	test $(git rev-parse :2:three) = $(git rev-parse L2:three) &&
+	test $(git rev-parse :3:three) = $(git rev-parse R2:three) &&
+
+	cp two merged &&
+	>empty &&
+	test_must_fail git merge-file \
+		-L "Temporary merge branch 2" \
+		-L "" \
+		-L "Temporary merge branch 1" \
+		merged empty one &&
+	test $(git rev-parse :1:three) = $(git hash-object merged)
+'
+
+#
+# Same as before, but modify L1 slightly:
+#
+#  L1m L2
+#   o---o
+#  / \ / \
+# o   X   ?
+#  \ / \ /
+#   o---o
+#  R1  R2
+#
+
+test_expect_success 'setup criss-cross + rename merges with basic modification' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	ten="0 1 2 3 4 5 6 7 8 9"
+	for i in $ten
+	do
+		echo line $i in a sample file
+	done >one &&
+	for i in $ten
+	do
+		echo line $i in another sample file
+	done >two &&
+	git add one two &&
+	test_tick && git commit -m initial &&
+
+	git branch L1 &&
+	git checkout -b R1 &&
+	git mv one three &&
+	echo more >>two &&
+	git add two &&
+	test_tick && git commit -m R1 &&
+
+	git checkout L1 &&
+	git mv two three &&
+	test_tick && git commit -m L1 &&
+
+	git checkout L1^0 &&
+	test_tick && git merge -s ours R1 &&
+	git tag L2 &&
+
+	git checkout R1^0 &&
+	test_tick && git merge -s ours L1 &&
+	git tag R2
+'
+
+test_expect_success 'merge criss-cross + rename merges with basic modification' '
+	git reset --hard &&
+	git checkout L2^0 &&
+
+	test_must_fail git merge -s recursive R2^0 &&
+
+	test 5 = $(git ls-files -s | wc -l) &&
+	test 3 = $(git ls-files -u | wc -l) &&
+	test 0 = $(git ls-files -o | wc -l) &&
+
+	test $(git rev-parse :0:one) = $(git rev-parse L2:one) &&
+	test $(git rev-parse :0:two) = $(git rev-parse R2:two) &&
+	test $(git rev-parse :2:three) = $(git rev-parse L2:three) &&
+	test $(git rev-parse :3:three) = $(git rev-parse R2:three) &&
+
+	head -n 10 two >merged &&
+	cp one merge-me &&
+	>empty &&
+	test_must_fail git merge-file \
+		-L "Temporary merge branch 2" \
+		-L "" \
+		-L "Temporary merge branch 1" \
+		merged empty merge-me &&
+	test $(git rev-parse :1:three) = $(git hash-object merged)
+'
+
+#
+# For the next test, we start with three commits in two lines of development
+# which setup a rename/add conflict:
+#   Commit A: File 'a' exists
+#   Commit B: Rename 'a' -> 'new_a'
+#   Commit C: Modify 'a', create different 'new_a'
+# Later, two different people merge and resolve differently:
+#   Commit D: Merge B & C, ignoring separately created 'new_a'
+#   Commit E: Merge B & C making use of some piece of secondary 'new_a'
+# Finally, someone goes to merge D & E.  Does git detect the conflict?
+#
+#      B   D
+#      o---o
+#     / \ / \
+#  A o   X   ? F
+#     \ / \ /
+#      o---o
+#      C   E
+#
+
+test_expect_success 'setup differently handled merges of rename/add conflict' '
+	git rm -rf . &&
+	git clean -fdqx &&
+	rm -rf .git &&
+	git init &&
+
+	printf "0\n1\n2\n3\n4\n5\n6\n7\n8\n9\n" >a &&
+	git add a &&
+	test_tick && git commit -m A &&
+
+	git branch B &&
+	git checkout -b C &&
+	echo 10 >>a &&
+	echo "other content" >>new_a &&
+	git add a new_a &&
+	test_tick && git commit -m C &&
+
+	git checkout B &&
+	git mv a new_a &&
+	test_tick && git commit -m B &&
+
+	git checkout B^0 &&
+	test_must_fail git merge C &&
+	git clean -f &&
+	test_tick && git commit -m D &&
+	git tag D &&
+
+	git checkout C^0 &&
+	test_must_fail git merge B &&
+	rm new_a~HEAD new_a &&
+	printf "Incorrectly merged content" >>new_a &&
+	git add -u &&
+	test_tick && git commit -m E &&
+	git tag E
+'
+
+test_expect_success 'git detects differently handled merges conflict' '
+	git reset --hard &&
+	git checkout D^0 &&
+
+	git merge -s recursive E^0 && {
+		echo "BAD: should have conflicted"
+		test "Incorrectly merged content" = "$(cat new_a)" &&
+			echo "BAD: Silently accepted wrong content"
+		return 1
+	}
+
+	test 3 = $(git ls-files -s | wc -l) &&
+	test 3 = $(git ls-files -u | wc -l) &&
+	test 0 = $(git ls-files -o | wc -l) &&
+
+	test $(git rev-parse :2:new_a) = $(git rev-parse D:new_a) &&
+	test $(git rev-parse :3:new_a) = $(git rev-parse E:new_a) &&
+
+	git cat-file -p B:new_a >>merged &&
+	git cat-file -p C:new_a >>merge-me &&
+	>empty &&
+	test_must_fail git merge-file \
+		-L "Temporary merge branch 2" \
+		-L "" \
+		-L "Temporary merge branch 1" \
+		merged empty merge-me &&
+	test $(git rev-parse :1:new_a) = $(git hash-object merged)
 '
 
 test_done