gitattributes: fix relative path matching

There was an embarrassing pair of off-by-one miscounting that
failed to match path "a/b/c" when "a/.gitattributes" tried to
name it with relative path "b/c".

This fixes it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

attr.c

@@ -406,7 +406,7 @@ static void debug_info(const char *what, struct attr_stack *elem)
 {
 	fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
 }
-static void debug_set(const char *what, const char *match, struct git_attr *attr, void *v)
+static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
 {
 	const char *value = v;
 
@@ -543,10 +543,10 @@ static int path_matches(const char *pathname, int pathlen,
 	if (*pattern == '/')
 		pattern++;
 	if (pathlen < baselen ||
-	    (baselen && pathname[baselen - 1] != '/') ||
+	    (baselen && pathname[baselen] != '/') ||
 	    strncmp(pathname, base, baselen))
 		return 0;
-	return fnmatch(pattern, pathname + baselen, FNM_PATHNAME) == 0;
+	return fnmatch(pattern, pathname + baselen + 1, FNM_PATHNAME) == 0;
 }
 
 static int fill_one(const char *what, struct match_attr *a, int rem)

t/t0003-attributes.sh

@@ -0,0 +1,49 @@
+#!/bin/sh
+
+test_description=gitattributes
+
+. ./test-lib.sh
+
+attr_check () {
+
+	path="$1"
+	expect="$2"
+
+	git check-attr test -- "$path" >actual &&
+	echo "$path: test: $2" >expect &&
+	diff -u expect actual
+
+}
+
+
+test_expect_success 'setup' '
+
+	mkdir -p a/b/d a/c &&
+	(
+		echo "f	test=f"
+	) >.gitattributes &&
+	(
+		echo "g test=a/g" &&
+		echo "b/g test=a/b/g"
+	) >a/.gitattributes &&
+	(
+		echo "h test=a/b/h" &&
+		echo "d/* test=a/b/d/*"
+	) >a/b/.gitattributes
+
+'
+
+test_expect_success 'attribute test' '
+
+	attr_check f f &&
+	attr_check a/f f &&
+	attr_check a/c/f f &&
+	attr_check a/g a/g &&
+	attr_check a/b/g a/b/g &&
+	attr_check b/g unspecified &&
+	attr_check a/b/h a/b/h &&
+	attr_check a/b/d/g "a/b/d/*"
+
+'
+
+test_done