introducing early check for pattern as done in filepath.Glob

match.go

@@ -32,6 +32,10 @@ import (
 // This was adapted from (http://golang.org/pkg/path/filepath) and uses several
 // built-ins from that package.
 func Glob(fs Fs, pattern string) (matches []string, err error) {
+	// Check pattern is well-formed.
+	if _, err := filepath.Match(pattern, ""); err != nil {
+		return nil, err
+	}
 	if !hasMeta(pattern) {
 		// Lstat not supported by a ll filesystems.
 		if _, err = lstatIfPossible(fs, pattern); err != nil {

match_test.go

@@ -174,9 +174,23 @@ func TestGlobSymlink(t *testing.T) {
 
 func TestGlobError(t *testing.T) {
 	for _, fs := range Fss {
-		_, err := Glob(fs, "[7]")
+		_, err := Glob(fs, "a/b[")
-		if err != nil {
+		if err == nil {
 			t.Error("expected error for bad pattern; got none")
 		}
 	}
 }
+
+func TestGlobErrorDirExistsAndContainsFile(t *testing.T) {
+	for _, fs := range Fss {
+		fs.Mkdir("a", os.ModePerm)
+		fs.OpenFile("a/a.txt", os.O_CREATE, os.ModePerm)
+		defer fs.RemoveAll("a")
+		_, err := Glob(fs, "a/b[")
+		if err == nil {
+			t.Error("expected error for bad pattern; got none")
+		}
+
+	}
+}
+