plumbing: gitignore, fix incorrect parsing. Fixes #500

Signed-off-by: Arieh Schneier <15041913+AriehSchneier@users.noreply.github.com>

2 files changed, 40 insertions, 6 deletions

diff --git a/plumbing/format/gitignore/dir_test.go b/plumbing/format/gitignore/dir_test.go
index 7cd37dd..4bbba68 100644
--- a/plumbing/format/gitignore/dir_test.go
+++ b/plumbing/format/gitignore/dir_test.go
@@ -64,6 +64,27 @@ func (s *MatcherSuite) SetUpTest(c *C) {
 	err = fs.MkdirAll("vendor/gopkg.in", os.ModePerm)
 	c.Assert(err, IsNil)
 
+	err = fs.MkdirAll("multiple/sub/ignores/first", os.ModePerm)
+	c.Assert(err, IsNil)
+	err = fs.MkdirAll("multiple/sub/ignores/second", os.ModePerm)
+	c.Assert(err, IsNil)
+	f, err = fs.Create("multiple/sub/ignores/first/.gitignore")
+	c.Assert(err, IsNil)
+	_, err = f.Write([]byte("ignore_dir\n"))
+	c.Assert(err, IsNil)
+	err = f.Close()
+	c.Assert(err, IsNil)
+	f, err = fs.Create("multiple/sub/ignores/second/.gitignore")
+	c.Assert(err, IsNil)
+	_, err = f.Write([]byte("ignore_dir\n"))
+	c.Assert(err, IsNil)
+	err = f.Close()
+	c.Assert(err, IsNil)
+	err = fs.MkdirAll("multiple/sub/ignores/first/ignore_dir", os.ModePerm)
+	c.Assert(err, IsNil)
+	err = fs.MkdirAll("multiple/sub/ignores/second/ignore_dir", os.ModePerm)
+	c.Assert(err, IsNil)
+
 	s.GFS = fs
 
 	// setup root that contains user home
@@ -211,15 +232,26 @@ func (s *MatcherSuite) SetUpTest(c *C) {
 }
 
 func (s *MatcherSuite) TestDir_ReadPatterns(c *C) {
+	checkPatterns := func(ps []Pattern) {
+		c.Assert(ps, HasLen, 6)
+		m := NewMatcher(ps)
+
+		c.Assert(m.Match([]string{"exclude.crlf"}, true), Equals, true)
+		c.Assert(m.Match([]string{"ignore.crlf"}, true), Equals, true)
+		c.Assert(m.Match([]string{"vendor", "gopkg.in"}, true), Equals, true)
+		c.Assert(m.Match([]string{"vendor", "github.com"}, true), Equals, false)
+		c.Assert(m.Match([]string{"multiple", "sub", "ignores", "first", "ignore_dir"}, true), Equals, true)
+		c.Assert(m.Match([]string{"multiple", "sub", "ignores", "second", "ignore_dir"}, true), Equals, true)
+	}
+
 	ps, err := ReadPatterns(s.GFS, nil)
 	c.Assert(err, IsNil)
-	c.Assert(ps, HasLen, 4)
+	checkPatterns(ps)
 
-	m := NewMatcher(ps)
-	c.Assert(m.Match([]string{"exclude.crlf"}, true), Equals, true)
-	c.Assert(m.Match([]string{"ignore.crlf"}, true), Equals, true)
-	c.Assert(m.Match([]string{"vendor", "gopkg.in"}, true), Equals, true)
-	c.Assert(m.Match([]string{"vendor", "github.com"}, true), Equals, false)
+	// passing an empty slice with capacity to check we don't hit a bug where the extra capacity is reused incorrectly
+	ps, err = ReadPatterns(s.GFS, make([]string, 0, 6))
+	c.Assert(err, IsNil)
+	checkPatterns(ps)
 }
 
 func (s *MatcherSuite) TestDir_ReadRelativeGlobalGitIgnore(c *C) {
diff --git a/plumbing/format/gitignore/pattern.go b/plumbing/format/gitignore/pattern.go
index 098cb50..450b3cd 100644
--- a/plumbing/format/gitignore/pattern.go
+++ b/plumbing/format/gitignore/pattern.go
@@ -39,6 +39,8 @@ type pattern struct {
 
 // ParsePattern parses a gitignore pattern string into the Pattern structure.
 func ParsePattern(p string, domain []string) Pattern {
+	// storing domain, copy it to ensure it isn't changed externally
+	domain = append([]string(nil), domain...)
 	res := pattern{domain: domain}
 
 	if strings.HasPrefix(p, inclusionPrefix) {