From d638d64572e1e0086c4e762aee95c6e7a5db1a9e Mon Sep 17 00:00:00 2001
From: Ben Luddy <bluddy@redhat.com>
Date: Wed, 16 Oct 2024 17:42:06 -0400
Subject: [PATCH] Add CBOR serializer option to disable JSON transcoding of raw
 types.

---
 .../pkg/runtime/serializer/cbor/cbor.go       | 25 ++++++++++++++---
 .../pkg/runtime/serializer/cbor/cbor_test.go  | 27 +++++++++++++++++++
 2 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor.go b/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor.go
index 46c1b009491..20fa7eb04cf 100644
--- a/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor.go
+++ b/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor.go
@@ -68,17 +68,30 @@ type Serializer interface {
 var _ Serializer = &serializer{}
 
 type options struct {
-	strict bool
+	strict    bool
+	transcode bool
 }
 
 type Option func(*options)
 
+// Strict configures a serializer to return a strict decoding error when it encounters map keys that
+// do not correspond to a field in the target object of a decode operation. This option is disabled
+// by default.
 func Strict(s bool) Option {
 	return func(opts *options) {
 		opts.strict = s
 	}
 }
 
+// Transcode configures a serializer to transcode the "raw" bytes of a decoded runtime.RawExtension
+// or metav1.FieldsV1 object to JSON. This is enabled by default to support existing programs that
+// depend on the assumption that objects of either type contain valid JSON.
+func Transcode(s bool) Option {
+	return func(opts *options) {
+		opts.transcode = s
+	}
+}
+
 type serializer struct {
 	metaFactory metaFactory
 	creater     runtime.ObjectCreater
@@ -88,6 +101,8 @@ type serializer struct {
 
 func (serializer) private() {}
 
+// NewSerializer creates and returns a serializer configured with the provided options. The default
+// options are equivalent to explicitly passing Strict(false) and Transcode(true).
 func NewSerializer(creater runtime.ObjectCreater, typer runtime.ObjectTyper, options ...Option) Serializer {
 	return newSerializer(&defaultMetaFactory{}, creater, typer, options...)
 }
@@ -98,6 +113,7 @@ func newSerializer(metaFactory metaFactory, creater runtime.ObjectCreater, typer
 		creater:     creater,
 		typer:       typer,
 	}
+	s.options.transcode = true
 	for _, o := range options {
 		o(&s.options)
 	}
@@ -337,9 +353,10 @@ func (s *serializer) Decode(data []byte, gvk *schema.GroupVersionKind, into runt
 		return nil, actual, err
 	}
 
-	// TODO: Make possible to disable this behavior.
-	if err := transcodeRawTypes(obj); err != nil {
-		return nil, actual, err
+	if s.options.transcode {
+		if err := transcodeRawTypes(obj); err != nil {
+			return nil, actual, err
+		}
 	}
 
 	return obj, actual, strict
diff --git a/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor_test.go b/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor_test.go
index a47858c6ad9..23894a06258 100644
--- a/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor_test.go
+++ b/staging/src/k8s.io/apimachinery/pkg/runtime/serializer/cbor/cbor_test.go
@@ -345,6 +345,33 @@ func TestDecode(t *testing.T) {
 				}
 			},
 		},
+		{
+			name:        "raw types not transcoded",
+			options:     []Option{Transcode(false)},
+			data:        []byte{0xa4, 0x41, 'f', 0xa1, 0x41, 'a', 0x01, 0x42, 'f', 'p', 0xa1, 0x41, 'z', 0x02, 0x41, 'r', 0xa1, 0x41, 'b', 0x03, 0x42, 'r', 'p', 0xa1, 0x41, 'y', 0x04},
+			gvk:         &schema.GroupVersionKind{},
+			metaFactory: stubMetaFactory{gvk: &schema.GroupVersionKind{}},
+			typer:       stubTyper{gvks: []schema.GroupVersionKind{{Group: "x", Version: "y", Kind: "z"}}},
+			into:        &structWithRawFields{},
+			expectedObj: &structWithRawFields{
+				FieldsV1:        metav1.FieldsV1{Raw: []byte{0xa1, 0x41, 'a', 0x01}},
+				FieldsV1Pointer: &metav1.FieldsV1{Raw: []byte{0xa1, 0x41, 'z', 0x02}},
+				// RawExtension's UnmarshalCBOR ensures the self-described CBOR tag
+				// is present in the result so that there is never any ambiguity in
+				// distinguishing CBOR from JSON or Protobuf. It is unnecessary for
+				// FieldsV1 to do the same because the initial byte is always
+				// sufficient to distinguish a valid JSON-encoded FieldsV1 from a
+				// valid CBOR-encoded FieldsV1.
+				RawExtension:        runtime.RawExtension{Raw: []byte{0xd9, 0xd9, 0xf7, 0xa1, 0x41, 'b', 0x03}},
+				RawExtensionPointer: &runtime.RawExtension{Raw: []byte{0xd9, 0xd9, 0xf7, 0xa1, 0x41, 'y', 0x04}},
+			},
+			expectedGVK: &schema.GroupVersionKind{Group: "x", Version: "y", Kind: "z"},
+			assertOnError: func(t *testing.T, err error) {
+				if err != nil {
+					t.Errorf("expected nil error, got: %v", err)
+				}
+			},
+		},
 		{
 			name:        "object with embedded typemeta and objectmeta",
 			data:        []byte("\xa2\x48metadata\xa1\x44name\x43foo\x44spec\xa0"), // {"metadata": {"name": "foo"}}