t6022: ignoring untracked files by merge-recursive when they do not matter

Signed-off-by: Junio C Hamano <junkio@cox.net>

t/t6022-merge-rename.sh

@@ -42,15 +42,20 @@ O OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO
 EOF
 
 git add A M &&
-git commit -m initial &&
+git commit -m "initial has A and M" &&
 git branch white &&
 git branch red &&
 git branch blue &&
+git branch yellow &&
 
 sed -e "/^g /s/.*/g : master changes a line/" <A >A+ &&
 mv A+ A &&
 git commit -a -m "master updates A" &&
 
+git checkout yellow &&
+rm -f M &&
+git commit -a -m "yellow removes M" &&
+
 git checkout white &&
 sed -e "/^g /s/.*/g : white changes a line/" <A >B &&
 sed -e "/^G /s/.*/G : colored branch changes a line/" <M >N &&
@@ -79,27 +84,27 @@ test_expect_success 'pull renaming branch into unrenaming one' \
 	git show-branch
 	git pull . white && {
 		echo "BAD: should have conflicted"
-		exit 1
+		return 1
 	}
 	git ls-files -s
 	test "$(git ls-files -u B | wc -l)" -eq 3 || {
 		echo "BAD: should have left stages for B"
-		exit 1	
+		return 1
 	}
 	test "$(git ls-files -s N | wc -l)" -eq 1 || {
 		echo "BAD: should have merged N"
-		exit 1	
+		return 1
 	}
 	sed -ne "/^g/{
 	p
 	q
 	}" B | grep master || {
 		echo "BAD: should have listed our change first"
-		exit 1
+		return 1
 	}
 	test "$(git diff white N | wc -l)" -eq 0 || {
 		echo "BAD: should have taken colored branch"
-		exit 1
+		return 1
 	}
 '
 
@@ -110,26 +115,26 @@ test_expect_success 'pull renaming branch into another renaming one' \
 	git checkout red
 	git pull . white && {
 		echo "BAD: should have conflicted"
-		exit 1
+		return 1
 	}
 	test "$(git ls-files -u B | wc -l)" -eq 3 || {
 		echo "BAD: should have left stages"
-		exit 1	
+		return 1
 	}
 	test "$(git ls-files -s N | wc -l)" -eq 1 || {
 		echo "BAD: should have merged N"
-		exit 1	
+		return 1
 	}
 	sed -ne "/^g/{
 	p
 	q
 	}" B | grep red || {
 		echo "BAD: should have listed our change first"
-		exit 1
+		return 1
 	}
 	test "$(git diff white N | wc -l)" -eq 0 || {
 		echo "BAD: should have taken colored branch"
-		exit 1
+		return 1
 	}
 '
 
@@ -139,26 +144,26 @@ test_expect_success 'pull unrenaming branch into renaming one' \
 	git show-branch
 	git pull . master && {
 		echo "BAD: should have conflicted"
-		exit 1
+		return 1
 	}
 	test "$(git ls-files -u B | wc -l)" -eq 3 || {
 		echo "BAD: should have left stages"
-		exit 1	
+		return 1
 	}
 	test "$(git ls-files -s N | wc -l)" -eq 1 || {
 		echo "BAD: should have merged N"
-		exit 1	
+		return 1
 	}
 	sed -ne "/^g/{
 	p
 	q
 	}" B | grep red || {
 		echo "BAD: should have listed our change first"
-		exit 1
+		return 1
 	}
 	test "$(git diff white N | wc -l)" -eq 0 || {
 		echo "BAD: should have taken colored branch"
-		exit 1
+		return 1
 	}
 '
 
@@ -168,35 +173,149 @@ test_expect_success 'pull conflicting renames' \
 	git show-branch
 	git pull . blue && {
 		echo "BAD: should have conflicted"
-		exit 1
+		return 1
 	}
 	test "$(git ls-files -u A | wc -l)" -eq 1 || {
 		echo "BAD: should have left a stage"
-		exit 1	
+		return 1
 	}
 	test "$(git ls-files -u B | wc -l)" -eq 1 || {
 		echo "BAD: should have left a stage"
-		exit 1	
+		return 1
 	}
 	test "$(git ls-files -u C | wc -l)" -eq 1 || {
 		echo "BAD: should have left a stage"
-		exit 1	
+		return 1
 	}
 	test "$(git ls-files -s N | wc -l)" -eq 1 || {
 		echo "BAD: should have merged N"
-		exit 1	
+		return 1
 	}
 	sed -ne "/^g/{
 	p
 	q
 	}" B | grep red || {
 		echo "BAD: should have listed our change first"
-		exit 1
+		return 1
 	}
 	test "$(git diff white N | wc -l)" -eq 0 || {
 		echo "BAD: should have taken colored branch"
-		exit 1
+		return 1
 	}
 '
 
+test_expect_success 'interference with untracked working tree file' '
+
+	git reset --hard
+	git show-branch
+	echo >A this file should not matter
+	git pull . white && {
+		echo "BAD: should have conflicted"
+		return 1
+	}
+	test -f A || {
+		echo "BAD: should have left A intact"
+		return 1
+	}
+'
+
+test_expect_success 'interference with untracked working tree file' '
+
+	git reset --hard
+	git checkout white
+	git show-branch
+	rm -f A
+	echo >A this file should not matter
+	git pull . red && {
+		echo "BAD: should have conflicted"
+		return 1
+	}
+	test -f A || {
+		echo "BAD: should have left A intact"
+		return 1
+	}
+'
+
+test_expect_success 'interference with untracked working tree file' '
+
+	git reset --hard
+	rm -f A M
+	git checkout -f master
+	git tag -f anchor
+	git show-branch
+	git pull . yellow || {
+		echo "BAD: should have cleanly merged"
+		return 1
+	}
+	test -f M && {
+		echo "BAD: should have removed M"
+		return 1
+	}
+	git reset --hard anchor
+'
+
+test_expect_success 'updated working tree file should prevent the merge' '
+
+	git reset --hard
+	rm -f A M
+	git checkout -f master
+	git tag -f anchor
+	git show-branch
+	echo >>M one line addition
+	cat M >M.saved
+	git pull . yellow && {
+		echo "BAD: should have complained"
+		return 1
+	}
+	diff M M.saved || {
+		echo "BAD: should have left M intact"
+		return 1
+	}
+	rm -f M.saved
+'
+
+test_expect_success 'updated working tree file should prevent the merge' '
+
+	git reset --hard
+	rm -f A M
+	git checkout -f master
+	git tag -f anchor
+	git show-branch
+	echo >>M one line addition
+	cat M >M.saved
+	git update-index M
+	git pull . yellow && {
+		echo "BAD: should have complained"
+		return 1
+	}
+	diff M M.saved || {
+		echo "BAD: should have left M intact"
+		return 1
+	}
+	rm -f M.saved
+'
+
+test_expect_success 'interference with untracked working tree file' '
+
+	git reset --hard
+	rm -f A M
+	git checkout -f yellow
+	git tag -f anchor
+	git show-branch
+	echo >M this file should not matter
+	git pull . master || {
+		echo "BAD: should have cleanly merged"
+		return 1
+	}
+	test -f M || {
+		echo "BAD: should have left M intact"
+		return 1
+	}
+	git ls-files -s | grep M && {
+		echo "BAD: M must be untracked in the result"
+		return 1
+	}
+	git reset --hard anchor
+'
+
 test_done