merge-recursive: fix rename/add conflict handling

This makes the rename/add conflict handling make use of the new
handle_file_collision() function, which fixes several bugs and improves
things for the rename/add case significantly.  Previously, rename/add
would:

  * Not leave any higher order stage entries in the index, making it
    appear as if there were no conflict.
  * Would place the rename file at the colliding path, and move the
    added file elsewhere, which combined with the lack of higher order
    stage entries felt really odd.  It's not clear to me why the
    rename should take precedence over the add; if one should be moved
    out of the way, they both probably should.
  * In the recursive case, it would do a two way merge of the added
    file and the version of the renamed file on the renamed side,
    completely excluding modifications to the renamed file on the
    unrenamed side of history.

Use the new handle_file_collision() to fix all of these issues.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 15 insertions, 13 deletions

diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6036-recursive-corner-cases.sh
index 3091cbc06a..d6b7e568f5 100755
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6036-recursive-corner-cases.sh
@@ -185,7 +185,7 @@ test_expect_success 'setup differently handled merges of rename/add conflict' '
 		git branch B &&
 		git checkout -b C &&
 		echo 10 >>a &&
-		echo "other content" >>new_a &&
+		test_write_lines 0 1 2 3 4 5 6 7 foobar >new_a &&
 		git add a new_a &&
 		test_tick && git commit -m C &&
 
@@ -195,14 +195,14 @@ test_expect_success 'setup differently handled merges of rename/add conflict' '
 
 		git checkout B^0 &&
 		test_must_fail git merge C &&
-		git clean -f &&
+		git show :2:new_a >new_a &&
+		git add new_a &&
 		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 &&
+		test_write_lines 0 1 2 3 4 5 6 7 bad_merge >new_a &&
 		git add -u &&
 		test_tick && git commit -m E &&
 		git tag E
@@ -225,21 +225,23 @@ test_expect_success 'git detects differently handled merges conflict' '
 		test_line_count = 1 out &&
 
 		git rev-parse >expect       \
-			D:new_a  E:new_a &&
+			C:new_a  D:new_a  E:new_a &&
 		git rev-parse   >actual     \
-			:2:new_a :3:new_a &&
+			:1:new_a :2:new_a :3:new_a &&
 		test_cmp expect actual &&
 
-		git cat-file -p C:new_a >ours &&
-		git cat-file -p B:new_a >theirs &&
+		# Test that the two-way merge in new_a is as expected
+		git cat-file -p D:new_a >ours &&
+		git cat-file -p E:new_a >theirs &&
 		>empty &&
 		test_must_fail git merge-file \
-			-L "Temporary merge branch 1" \
+			-L "HEAD" \
 			-L "" \
-			-L "Temporary merge branch 2" \
+			-L "E^0" \
 			ours empty theirs &&
 		sed -e "s/^\([<=>]\)/\1\1\1/" ours >expect &&
-		git cat-file -p :1:new_a >actual &&
+		git hash-object new_a >actual &&
+		git hash-object ours  >expect &&
 		test_cmp expect actual
 	)
 '
diff --git a/t/t6042-merge-rename-corner-cases.sh b/t/t6042-merge-rename-corner-cases.sh
index 23c3b6dffa..3e934ae89e 100755
--- a/t/t6042-merge-rename-corner-cases.sh
+++ b/t/t6042-merge-rename-corner-cases.sh
@@ -1095,8 +1095,8 @@ test_conflicts_with_adds_and_renames() {
 }
 
 test_conflicts_with_adds_and_renames rename rename failure
-test_conflicts_with_adds_and_renames rename add    failure
-test_conflicts_with_adds_and_renames add    rename failure
+test_conflicts_with_adds_and_renames rename add    success
+test_conflicts_with_adds_and_renames add    rename success
 test_conflicts_with_adds_and_renames add    add    success
 
 # Setup: