variable shadowing of token (#503)

* Added test for $INCLUDE statement parser in zone files

* FIX: localized l to switch statement, shadowed later call to os.Open(l.token)

scan.go

@@ -278,8 +278,7 @@ func parseZone(r io.Reader, origin, f string, t chan *Token, include int) {
 				return
 			}
 			neworigin := origin // There may be optionally a new origin set after the filename, if not use current one
-			l := <-c
-			switch l.value {
+			switch l := <-c; l.value {
 			case zBlank:
 				l := <-c
 				if l.value == zString {

scan_test.go

@@ -0,0 +1,45 @@
+package dns
+
+import (
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestParseZoneInclude(t *testing.T) {
+
+	tmpfile, err := ioutil.TempFile("", "dns")
+	if err != nil {
+		t.Fatalf("could not create tmpfile for test: %s", err)
+	}
+
+	if _, err := tmpfile.WriteString("foo\tIN\tA\t127.0.0.1"); err != nil {
+		t.Fatalf("unable to write content to tmpfile %q: %s", tmpfile.Name(), err)
+	}
+	if err := tmpfile.Close(); err != nil {
+		t.Fatalf("could not close tmpfile %q: %s", tmpfile.Name(), err)
+	}
+
+	zone := "$INCLUDE " + tmpfile.Name()
+
+	tok := ParseZone(strings.NewReader(zone), "", "")
+	for x := range tok {
+		if x.Error != nil {
+			t.Fatalf("expected no error, but got %s", x.Error)
+		}
+	}
+
+	os.Remove(tmpfile.Name())
+
+	tok = ParseZone(strings.NewReader(zone), "", "")
+	for x := range tok {
+		if x.Error == nil {
+			t.Fatalf("expected first token to contain an error but it didn't")
+		}
+		if !strings.Contains(x.Error.Error(), "failed to open") ||
+			!strings.Contains(x.Error.Error(), tmpfile.Name()) {
+			t.Fatalf(`expected error to contain: "failed to open" and %q but got: %s`, tmpfile.Name(), x.Error)
+		}
+	}
+}