Fixed IsInsideDir for paths on different filesystems

Author: cmaglie

paths.go

@@ -191,7 +191,10 @@ func (p *Path) Clean() *Path {
 func (p *Path) IsInsideDir(dir *Path) (bool, error) {
 	rel, err := filepath.Rel(dir.path, p.path)
 	if err != nil {
-		return false, err
+		// If the dir cannot be made relative to this path it means
+		// that it belong to a different filesystems, so it cannot be
+		// inside this path.
+		return false, nil
 	}
 	return !strings.Contains(rel, ".."+string(os.PathSeparator)) && rel != ".." && rel != ".", nil
 }

paths_test.go

@@ -154,16 +154,17 @@ func TestResetStatCacheWhenFollowingSymlink(t *testing.T) {
 }
 
 func TestIsInsideDir(t *testing.T) {
-	inside := func(a, b *Path) {
+	notInside := func(a, b *Path) {
 		in, err := a.IsInsideDir(b)
 		require.NoError(t, err)
-		require.True(t, in, "%s is inside %s", a, b)
+		require.False(t, in, "%s is inside %s", a, b)
 	}
 
-	notInside := func(a, b *Path) {
+	inside := func(a, b *Path) {
 		in, err := a.IsInsideDir(b)
 		require.NoError(t, err)
-		require.False(t, in, "%s is inside %s", a, b)
+		require.True(t, in, "%s is inside %s", a, b)
+		notInside(b, a)
 	}
 
 	f1 := New("/a/b/c")
@@ -196,6 +197,14 @@ func TestIsInsideDir(t *testing.T) {
 	f5 := New("/home/megabug/a15/packages")
 	notInside(f5, f4)
 	notInside(f4, f5)
+
+	if runtime.GOOS == "windows" {
+		f6 := New("C:\\", "A")
+		f7 := New("C:\\", "A", "B", "C")
+		f8 := New("E:\\", "A", "B", "C")
+		inside(f7, f6)
+		notInside(f8, f6)
+	}
 }
 
 func TestReadFileAsLines(t *testing.T) {