template: fixed html formatter bug where it would turn a []byte

into a string of decimal numbers.

R=r, rsc
CC=golang-dev
https://golang.org/cl/624041

src/pkg/template/format.go

@@ -61,7 +61,11 @@ func HTMLEscape(w io.Writer, s []byte) {
 
 // HTMLFormatter formats arbitrary values for HTML
 func HTMLFormatter(w io.Writer, value interface{}, format string) {
-	var b bytes.Buffer
-	fmt.Fprint(&b, value)
-	HTMLEscape(w, b.Bytes())
+	b, ok := value.([]byte)
+	if !ok {
+		var buf bytes.Buffer
+		fmt.Fprint(&buf, value)
+		b = buf.Bytes()
+	}
+	HTMLEscape(w, b)
 }

src/pkg/template/template_test.go

@@ -565,3 +565,14 @@ func TestVarIndirection(t *testing.T) {
 		t.Errorf("for %q: expected %q got %q", input, expect, buf.String())
 	}
 }
+
+func TestHTMLFormatterWithByte(t *testing.T) {
+	s := "Test string."
+	b := []byte(s)
+	var buf bytes.Buffer
+	HTMLFormatter(&buf, b, "")
+	bs := buf.String()
+	if bs != s {
+		t.Errorf("munged []byte, expected: %s got: %s", s, bs)
+	}
+}