dir.c: fix EXC_FLAG_MUSTBEDIR match in sparse checkout

Commit c84de70 (excluded_1(): support exclude files in index -
2009-08-20) tries to work around the fact that there is no
directory/file information in index entries, therefore
EXC_FLAG_MUSTBEDIR match would fail.

Unfortunately the workaround is flawed. This fixes it.

Reported-by: Thomas Rinderknecht <thomasr@sailguy.org>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

dir.c

@@ -360,7 +360,8 @@ int excluded_from_list(const char *pathname,
 
 			if (x->flags & EXC_FLAG_MUSTBEDIR) {
 				if (!dtype) {
-					if (!prefixcmp(pathname, exclude))
+					if (!prefixcmp(pathname, exclude) &&
+					    pathname[x->patternlen] == '/')
 						return to_exclude;
 					else
 						continue;

t/t1011-read-tree-sparse-checkout.sh

@@ -17,17 +17,19 @@ test_expect_success 'setup' '
 	cat >expected <<-\EOF &&
 	100644 77f0ba1734ed79d12881f81b36ee134de6a3327b 0	init.t
 	100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0	sub/added
+	100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0	subsub/added
 	EOF
 	cat >expected.swt <<-\EOF &&
 	H init.t
 	H sub/added
+	H subsub/added
 	EOF
 
 	test_commit init &&
 	echo modified >>init.t &&
-	mkdir sub &&
+	mkdir sub subsub &&
-	touch sub/added &&
+	touch sub/added subsub/added &&
-	git add init.t sub/added &&
+	git add init.t sub/added subsub/added &&
 	git commit -m "modified and added" &&
 	git tag top &&
 	git rm sub/added &&
@@ -81,6 +83,7 @@ test_expect_success 'match directories with trailing slash' '
 	cat >expected.swt-noinit <<-\EOF &&
 	S init.t
 	H sub/added
+	S subsub/added
 	EOF
 
 	echo sub/ > .git/info/sparse-checkout &&
@@ -105,6 +108,7 @@ test_expect_success 'checkout area changes' '
 	cat >expected.swt-nosub <<-\EOF &&
 	H init.t
 	S sub/added
+	S subsub/added
 	EOF
 
 	echo init.t >.git/info/sparse-checkout &&