Small cleanups, no change in exec.

pkg/fs/fakefs.go

@@ -102,6 +102,11 @@ func (fs *fakeFs) Open(name string) (File, error) {
 	return fs.m[name], nil
 }
 
+// EvalSymlinks does nothing and cannot fail.
+func (fs *fakeFs) EvalSymlinks(path string) (string, error) {
+	return path, nil
+}
+
 // Exists returns true if file is known.
 func (fs *fakeFs) Exists(name string) bool {
 	_, found := fs.m[name]

pkg/fs/fs.go

@@ -30,6 +30,7 @@ type FileSystem interface {
 	RemoveAll(name string) error
 	Open(name string) (File, error)
 	IsDir(name string) bool
+	EvalSymlinks(path string) (string, error)
 	Exists(name string) bool
 	Glob(pattern string) ([]string, error)
 	ReadFile(name string) ([]byte, error)

pkg/fs/realfs.go

@@ -53,6 +53,11 @@ func (realFS) RemoveAll(name string) error {
 // Open delegates to os.Open.
 func (realFS) Open(name string) (File, error) { return os.Open(name) }
 
+// EvalSymlinks delegates to filepath.EvalSymlinks.
+func (realFS) EvalSymlinks(path string) (string, error) {
+	return filepath.EvalSymlinks(path)
+}
+
 // Exists returns true if os.Stat succeeds.
 func (realFS) Exists(name string) bool {
 	_, err := os.Stat(name)