Don't panic if the feature-gate flag was not used

pkg/util/config/feature_gate.go

@@ -156,11 +156,10 @@ func (f *featureGate) Type() string {
 
 func (f *featureGate) lookup(key string) bool {
 	defaultValue := f.known[key].enabled
-	if f.enabled == nil {
-		panic(fmt.Sprintf("--%s has not been parsed", flagName))
-	}
-	if v, ok := f.enabled[key]; ok {
-		return v
+	if f.enabled != nil {
+		if v, ok := f.enabled[key]; ok {
+			return v
+		}
 	}
 	return defaultValue
 

pkg/util/config/feature_gate_test.go

@@ -139,3 +139,21 @@ func TestFeatureGateFlag(t *testing.T) {
 		}
 	}
 }
+
+func TestFeatureGateFlagDefaults(t *testing.T) {
+	// gates for testing
+	const testAlphaGate = "TestAlpha"
+	const testBetaGate = "TestBeta"
+
+	// Don't parse the flag, assert defaults are used.
+	f := DefaultFeatureGate
+	f.known[testAlphaGate] = featureSpec{false, alpha}
+	f.known[testBetaGate] = featureSpec{true, beta}
+
+	if f.lookup(testAlphaGate) != false {
+		t.Errorf("Expected false")
+	}
+	if f.lookup(testBetaGate) != true {
+		t.Errorf("Expected true")
+	}
+}