fix: handle x-kubernetes-preserve-unknown-fields (#325)

* fix: handle missing type in schema when x-kubernetes-preserve-unknown-fields is present

---------

Co-authored-by: John Knutson <john.knutson@hennepin.us>

pkg/graph/emulator/emulator.go

@@ -81,6 +81,11 @@ func (e *Emulator) generateValue(schema *spec.Schema) (interface{}, error) {
 		return nil, fmt.Errorf("schema is nil")
 	}
 
+	if enabled, ok := schema.VendorExtensible.Extensions["x-kubernetes-preserve-unknown-fields"]; ok && enabled.(bool) {
+		// Handle x-kubernetes-preserve-unknown-fields
+		return e.generateObject(schema)
+	}
+
 	if enabled, ok := schema.VendorExtensible.Extensions["x-kubernetes-int-or-string"]; ok && enabled.(bool) {
 		// Default to integer for dummy CRs
 		return e.generateInteger(schema), nil

pkg/graph/emulator/emulator_test.go

@@ -501,6 +501,24 @@ func TestGenerateValueWithIntOrString(t *testing.T) {
 
 }
 
+func TestGenerateValueWithPreserveUnknownFields(t *testing.T) {
+	e := NewEmulator()
+
+	t.Run("x-kubernetes-preserve-unknown-fields present, does not produce error", func(t *testing.T) {
+		schema := &spec.Schema{
+			VendorExtensible: spec.VendorExtensible{
+				Extensions: map[string]interface{}{
+					"x-kubernetes-preserve-unknown-fields": true,
+				},
+			},
+		}
+
+		_, err := e.generateValue(schema)
+		require.NoError(t, err)
+	})
+
+}
+
 func ptr[T comparable](v T) *T {
 	return &v
 }