git-apply: guess correct -p<n> value for non-git patches.

This enhances the third point in the previous commit.  When
applying a non-git patch that begins like this:

	--- 2.6.orig/mm/slab.c
	+++ 2.6/mm/slab.c
	@@ -N,M +L,K @@@
	...

and if you are in 'mm' subdirectory, we notice that -p2 is the
right option to use to apply the patch in file slab.c in the
current directory (i.e. mm/slab.c)

The guess function also knows about this pattern, where you
would need to use -p0 if applying from the top-level:

	--- mm/slab.c
	+++ mm/slab.c
	@@ -N,M +L,K @@@
	...

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

1 files changed, 54 insertions, 2 deletions

diff --git a/t/t4119-apply-config.sh b/t/t4119-apply-config.sh
index 32e0d71..55f4673 100755
--- a/t/t4119-apply-config.sh
+++ b/t/t4119-apply-config.sh
@@ -19,7 +19,7 @@ test_expect_success setup '
 '
 
 # Also handcraft GNU diff output; note this has trailing whitespace.
-cat >gpatch.file <<\EOF
+cat >gpatch.file <<\EOF &&
 --- file1	2007-02-21 01:04:24.000000000 -0800
 +++ file1+	2007-02-21 01:07:44.000000000 -0800
 @@ -1 +1 @@
@@ -27,6 +27,12 @@ cat >gpatch.file <<\EOF
 +B 
 EOF
 
+sed -e 's|file1|sub/&|' gpatch.file >gpatch-sub.file &&
+sed -e '
+	/^--- /s|file1|a/sub/&|
+	/^+++ /s|file1|b/sub/&|
+' gpatch.file >gpatch-ab-sub.file &&
+
 test_expect_success 'apply --whitespace=strip' '
 
 	rm -f sub/file1 &&
@@ -124,7 +130,53 @@ test_expect_success 'same in subdir but with traditional patch input' '
 	git update-index --refresh &&
 
 	cd sub &&
-	git apply -p0 ../gpatch.file &&
+	git apply ../gpatch.file &&
+	if grep " " file1
+	then
+		echo "Eh?"
+		false
+	elif grep B file1
+	then
+		echo Happy
+	else
+		echo "Huh?"
+		false
+	fi
+'
+
+test_expect_success 'same but with traditional patch input of depth 1' '
+
+	cd "$D" &&
+	git config apply.whitespace strip &&
+	rm -f sub/file1 &&
+	cp saved sub/file1 &&
+	git update-index --refresh &&
+
+	cd sub &&
+	git apply ../gpatch-sub.file &&
+	if grep " " file1
+	then
+		echo "Eh?"
+		false
+	elif grep B file1
+	then
+		echo Happy
+	else
+		echo "Huh?"
+		false
+	fi
+'
+
+test_expect_success 'same but with traditional patch input of depth 2' '
+
+	cd "$D" &&
+	git config apply.whitespace strip &&
+	rm -f sub/file1 &&
+	cp saved sub/file1 &&
+	git update-index --refresh &&
+
+	cd sub &&
+	git apply ../gpatch-ab-sub.file &&
 	if grep " " file1
 	then
 		echo "Eh?"