Merge branch 'jc/fix-tree-walk'

* jc/fix-tree-walk:
  read-tree --debug-unpack
  unpack-trees.c: look ahead in the index
  unpack-trees.c: prepare for looking ahead in the index
  Aggressive three-way merge: fix D/F case
  traverse_trees(): handle D/F conflict case sanely
  more D/F conflict tests
  tests: move convenience regexp to match object names to test-lib.sh

Conflicts:
	builtin-read-tree.c
	unpack-trees.c
	unpack-trees.h

11 files changed, 110 insertions, 20 deletions

diff --git a/t/diff-lib.sh b/t/diff-lib.sh
index 4bddeb591..75a35fcd0 100644
--- a/t/diff-lib.sh
+++ b/t/diff-lib.sh
@@ -1,7 +1,5 @@
 :
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 sanitize_diff_raw='/^:/s/ '"$_x40"' '"$_x40"' \([A-Z]\)[0-9]*	/ X X \1#	/'
 compare_diff_raw () {
     # When heuristics are improved, the score numbers would change.
diff --git a/t/t1000-read-tree-m-3way.sh b/t/t1000-read-tree-m-3way.sh
index 22ba7a544..4f171722d 100755
--- a/t/t1000-read-tree-m-3way.sh
+++ b/t/t1000-read-tree-m-3way.sh
@@ -126,9 +126,6 @@ cat >expected <<\EOF
 100644 X 0	Z/NN
 EOF
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
-
 check_result () {
     git ls-files --stage | sed -e 's/ '"$_x40"' / X /' >current &&
     test_cmp expected current
diff --git a/t/t1001-read-tree-m-2way.sh b/t/t1001-read-tree-m-2way.sh
index c2d408b46..6327d205c 100755
--- a/t/t1001-read-tree-m-2way.sh
+++ b/t/t1001-read-tree-m-2way.sh
@@ -26,8 +26,6 @@ read_tree_twoway () {
     git read-tree -m "$1" "$2" && git ls-files --stage
 }
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 compare_change () {
 	sed -n >current \
 	    -e '/^--- /d; /^+++ /d; /^@@ /d;' \
diff --git a/t/t1002-read-tree-m-u-2way.sh b/t/t1002-read-tree-m-u-2way.sh
index 5e40cec53..0241329a0 100755
--- a/t/t1002-read-tree-m-u-2way.sh
+++ b/t/t1002-read-tree-m-u-2way.sh
@@ -10,8 +10,6 @@ This is identical to t1001, but uses -u to update the work tree as well.
 '
 . ./test-lib.sh
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 compare_change () {
 	sed >current \
 	    -e '1{/^diff --git /d;}' \
diff --git a/t/t1012-read-tree-df.sh b/t/t1012-read-tree-df.sh
new file mode 100755
index 000000000..9811d467d
--- /dev/null
+++ b/t/t1012-read-tree-df.sh
@@ -0,0 +1,102 @@
+#!/bin/sh
+
+test_description='read-tree D/F conflict corner cases'
+
+. ./test-lib.sh
+
+maketree () {
+	(
+		rm -f .git/index .git/index.lock &&
+		git clean -d -f -f -q -x &&
+		name="$1" &&
+		shift &&
+		for it
+		do
+			path=$(expr "$it" : '\([^:]*\)') &&
+			mkdir -p $(dirname "$path") &&
+			echo "$it" >"$path" &&
+			git update-index --add "$path" || exit
+		done &&
+		git tag "$name" $(git write-tree)
+	)
+}
+
+settree () {
+	rm -f .git/index .git/index.lock &&
+	git clean -d -f -f -q -x &&
+	git read-tree "$1" &&
+	git checkout-index -f -q -u -a &&
+	git update-index --refresh
+}
+
+checkindex () {
+	git ls-files -s |
+	sed "s|^[0-7][0-7]* $_x40 \([0-3]\)	|\1 |" >current &&
+	cat >expect &&
+	test_cmp expect current
+}
+
+test_expect_success setup '
+	maketree O-000 a/b-2/c/d a/b/c/d a/x &&
+	maketree A-000 a/b-2/c/d a/b/c/d a/x &&
+	maketree A-001 a/b-2/c/d a/b/c/d a/b/c/e a/x &&
+	maketree B-000 a/b-2/c/d a/b     a/x &&
+
+	maketree O-010 t-0     t/1  t/2 t=3 &&
+	maketree A-010 t-0 t            t=3 &&
+	maketree B-010         t/1:     t=3: &&
+
+	maketree O-020 ds/dma/ioat.c ds/dma/ioat_dca.c &&
+	maketree A-020 ds/dma/ioat/Makefile ds/dma/ioat/registers.h &&
+	:
+'
+
+test_expect_success '3-way (1)' '
+	settree A-000 &&
+	git read-tree -m -u O-000 A-000 B-000 &&
+	checkindex <<-EOF
+	3 a/b
+	0 a/b-2/c/d
+	1 a/b/c/d
+	2 a/b/c/d
+	0 a/x
+	EOF
+'
+
+test_expect_success '3-way (2)' '
+	settree A-001 &&
+	git read-tree -m -u O-000 A-001 B-000 &&
+	checkindex <<-EOF
+	3 a/b
+	0 a/b-2/c/d
+	1 a/b/c/d
+	2 a/b/c/d
+	2 a/b/c/e
+	0 a/x
+	EOF
+'
+
+test_expect_success '3-way (3)' '
+	settree A-010 &&
+	git read-tree -m -u O-010 A-010 B-010 &&
+	checkindex <<-EOF
+	2 t
+	1 t-0
+	2 t-0
+	1 t/1
+	3 t/1
+	1 t/2
+	0 t=3
+	EOF
+'
+
+test_expect_success '2-way (1)' '
+	settree O-020 &&
+	git read-tree -m -u O-020 A-020 &&
+	checkindex <<-EOF
+	0 ds/dma/ioat/Makefile
+	0 ds/dma/ioat/registers.h
+	EOF
+'
+
+test_done
diff --git a/t/t3100-ls-tree-restrict.sh b/t/t3100-ls-tree-restrict.sh
index ee60d03fe..eee0d344d 100755
--- a/t/t3100-ls-tree-restrict.sh
+++ b/t/t3100-ls-tree-restrict.sh
@@ -43,8 +43,6 @@ test_expect_success \
      tree=`git write-tree` &&
      echo $tree'
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 test_output () {
     sed -e "s/ $_x40	/ X	/" <current >check
     test_cmp expected check
diff --git a/t/t3101-ls-tree-dirname.sh b/t/t3101-ls-tree-dirname.sh
index 8be9fb411..06654c6f8 100755
--- a/t/t3101-ls-tree-dirname.sh
+++ b/t/t3101-ls-tree-dirname.sh
@@ -39,8 +39,6 @@ test_expect_success \
      tree=`git write-tree` &&
      echo $tree'
 
-_x05='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x05$_x05$_x05$_x05$_x05$_x05$_x05$_x05"
 test_output () {
     sed -e "s/ $_x40	/ X	/" <current >check
     test_cmp expected check
diff --git a/t/t4006-diff-mode.sh b/t/t4006-diff-mode.sh
index 8c1b81e24..ff8c2f753 100755
--- a/t/t4006-diff-mode.sh
+++ b/t/t4006-diff-mode.sh
@@ -20,8 +20,6 @@ test_expect_success \
     'test_chmod +x rezrov &&
      git diff-index $tree >current'
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 sed -e 's/\(:100644 100755\) \('"$_x40"'\) \2 /\1 X X /' <current >check
 echo ":100644 100755 X X M	rezrov" >expected
 
diff --git a/t/t6012-rev-list-simplify.sh b/t/t6012-rev-list-simplify.sh
index 510bb9679..af34a1e81 100755
--- a/t/t6012-rev-list-simplify.sh
+++ b/t/t6012-rev-list-simplify.sh
@@ -8,9 +8,6 @@ note () {
 	git tag "$1"
 }
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
-
 unnote () {
 	git name-rev --tags --stdin | sed -e "s|$_x40 (tags/\([^)]*\)) |\1 |g"
 }
diff --git a/t/t6035-merge-dir-to-symlink.sh b/t/t6035-merge-dir-to-symlink.sh
index 5b96fb0b3..d1b22871c 100755
--- a/t/t6035-merge-dir-to-symlink.sh
+++ b/t/t6035-merge-dir-to-symlink.sh
@@ -48,7 +48,7 @@ test_expect_success 'setup for merge test' '
 	git tag baseline
 '
 
-test_expect_success 'do not lose a/b-2/c/d in merge (resolve)' '
+test_expect_failure 'do not lose a/b-2/c/d in merge (resolve)' '
 	git reset --hard &&
 	git checkout baseline^0 &&
 	git merge -s resolve master &&
@@ -74,7 +74,7 @@ test_expect_success 'setup a merge where dir a/b-2 changed to symlink' '
 	git tag test2
 '
 
-test_expect_failure 'merge should not have conflicts (resolve)' '
+test_expect_success 'merge should not have conflicts (resolve)' '
 	git reset --hard &&
 	git checkout baseline^0 &&
 	git merge -s resolve test2 &&
diff --git a/t/test-lib.sh b/t/test-lib.sh
index c1476f9a2..baa409307 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -74,6 +74,12 @@ case $(echo $GIT_TRACE |tr "[A-Z]" "[a-z]") in
 		;;
 esac
 
+# Convenience
+#
+# A regexp to match 5 and 40 hexdigits
+_x05='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
+_x40="$_x05$_x05$_x05$_x05$_x05$_x05$_x05$_x05"
+
 # Each test should start with something like this, after copyright notices:
 #
 # test_description='Description of this test...