GODRIVER-2866 Update method signatures of bson.ValueMarshaler/`bson…

….ValueUnmarshaler` to only use basic types.

bson/default_value_decoders.go

@@ -1280,7 +1280,7 @@ func (dvd DefaultValueDecoders) ValueUnmarshalerDecodeValue(_ DecodeContext, vr
 		// NB: this error should be unreachable due to the above checks
 		return ValueDecoderError{Name: "ValueUnmarshalerDecodeValue", Types: []reflect.Type{tValueUnmarshaler}, Received: val}
 	}
-	return m.UnmarshalBSONValue(t, src)
+	return m.UnmarshalBSONValue(byte(t), src)
 }
 
 // UnmarshalerDecodeValue is the ValueDecoderFunc for Unmarshaler implementations.

bson/default_value_encoders.go

@@ -569,7 +569,7 @@ func (dve DefaultValueEncoders) ValueMarshalerEncodeValue(_ EncodeContext, vw Va
 	if err != nil {
 		return err
 	}
-	return copyValueFromBytes(vw, t, data)
+	return copyValueFromBytes(vw, Type(t), data)
 }
 
 // MarshalerEncodeValue is the ValueEncoderFunc for Marshaler implementations.

bson/marshal.go

@@ -34,7 +34,7 @@ type Marshaler interface {
 // create custom BSON marshaling behavior for an entire BSON document, implement
 // the Marshaler interface instead.
 type ValueMarshaler interface {
-	MarshalBSONValue() (Type, []byte, error)
+	MarshalBSONValue() (byte, []byte, error)
 }
 
 // Pool of buffers for marshalling BSON.

bson/marshal_value_cases_test.go

@@ -37,13 +37,13 @@ type marshalValueMarshaler struct {
 
 var _ ValueMarshaler = marshalValueMarshaler{}
 
-func (mvi marshalValueMarshaler) MarshalBSONValue() (Type, []byte, error) {
-	return TypeInt32, bsoncore.AppendInt32(nil, int32(mvi.Foo)), nil
+func (mvi marshalValueMarshaler) MarshalBSONValue() (byte, []byte, error) {
+	return byte(TypeInt32), bsoncore.AppendInt32(nil, int32(mvi.Foo)), nil
 }
 
 var _ ValueUnmarshaler = &marshalValueMarshaler{}
 
-func (mvi *marshalValueMarshaler) UnmarshalBSONValue(_ Type, b []byte) error {
+func (mvi *marshalValueMarshaler) UnmarshalBSONValue(_ byte, b []byte) error {
 	v, _, _ := bsoncore.ReadInt32(b)
 	mvi.Foo = int(v)
 	return nil

bson/unmarshal.go

@@ -31,7 +31,7 @@ type Unmarshaler interface {
 // document. To create custom BSON unmarshaling behavior for an entire BSON
 // document, implement the Unmarshaler interface instead.
 type ValueUnmarshaler interface {
-	UnmarshalBSONValue(Type, []byte) error
+	UnmarshalBSONValue(byte, []byte) error
 }
 
 // Unmarshal parses the BSON-encoded data and stores the result in the value

mongo/mongo.go

@@ -229,8 +229,8 @@ func marshalAggregatePipeline(
 		if err != nil {
 			return nil, false, err
 		}
-		if btype != bson.TypeArray {
-			return nil, false, fmt.Errorf("ValueMarshaler returned a %v, but was expecting %v", btype, bson.TypeArray)
+		if typ := bson.Type(btype); typ != bson.TypeArray {
+			return nil, false, fmt.Errorf("ValueMarshaler returned a %v, but was expecting %v", typ, bson.TypeArray)
 		}
 
 		var hasOutputStage bool

mongo/mongo_test.go

@@ -616,6 +616,6 @@ type bvMarsh struct {
 	err  error
 }
 
-func (b bvMarsh) MarshalBSONValue() (bson.Type, []byte, error) {
-	return b.t, b.data, b.err
+func (b bvMarsh) MarshalBSONValue() (byte, []byte, error) {
+	return byte(b.t), b.data, b.err
 }