From 5bd0da8ddac527e265acc4243801fb348cf8df83 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Tue, 10 Jun 2025 19:57:03 -0400
Subject: [PATCH 1/9] Oneof rule

---
 .../validate/conformance/cases/messages.proto |  18 +
 .../protovalidate/buf/validate/validate.proto |  20 +
 .../validate/conformance/cases/messages.pb.go | 216 +++++++-
 .../internal/gen/buf/validate/validate.pb.go  | 488 ++++++++++--------
 .../internal/cases/cases_message.go           |  31 ++
 5 files changed, 550 insertions(+), 223 deletions(-)

diff --git a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
index cba86bf4..40e6ff64 100644
--- a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
+++ b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
@@ -58,3 +58,21 @@ message MessageRequiredOneof {
 }
 
 message MessageWith3dInside {}
+
+message MessageOneofSingleField {
+   option (buf.validate.message).oneof = { fields: ["str_field"] };
+   string str_field = 1;
+   bool bool_field = 2;
+}
+
+message MessageOneofMultipleFields {
+   option (buf.validate.message).oneof = { fields: ["str_field", "bool_field"] };
+   string str_field = 1;
+   bool bool_field = 2;
+}
+
+message MessageOneofMultipleFieldsRequired {
+   option (buf.validate.message).oneof = { fields: ["str_field", "bool_field"], required: true };
+   string str_field = 1;
+   bool bool_field = 2;
+}
diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index ef6029ab..5765396d 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -137,6 +137,26 @@ message MessageRules {
   // }
   // ```
   repeated Rule cel = 3;
+
+  // `oneof` is a repeated field of type MessageOneofRule that specifies a list of fields
+  // of which exactly one can be present. If `required` is also specified, then exactly one
+  // of the specified fields _must_ be present.
+  //
+  //
+  // ```proto
+  // message MyMessage {
+  //   // Only one of 'field1' or 'field2' _can_ be present in this message. 
+  //   option (buf.validate.message).oneof = { fields: ["field1", "field2"] };
+  //   // Only one of 'field3' or 'field4' _must_ be present in this message. 
+  //   option (buf.validate.message).oneof = { fields: ["field3", "field4"], required: true };
+  // }
+  // ```
+  repeated MessageOneofRule oneof = 4;
+}
+
+message MessageOneofRule {
+  repeated string fields = 1;
+  optional bool required = 2;
 }
 
 // The `OneofRules` message type enables you to manage rules for
diff --git a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
index a9ec2546..3e40533c 100644
--- a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
+++ b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
@@ -499,6 +499,162 @@ func (*MessageWith3DInside) Descriptor() ([]byte, []int) {
 	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{9}
 }
 
+type MessageOneofSingleField struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	StrField      string                 `protobuf:"bytes,1,opt,name=str_field,json=strField,proto3" json:"str_field,omitempty"`
+	BoolField     bool                   `protobuf:"varint,2,opt,name=bool_field,json=boolField,proto3" json:"bool_field,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *MessageOneofSingleField) Reset() {
+	*x = MessageOneofSingleField{}
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[10]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *MessageOneofSingleField) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageOneofSingleField) ProtoMessage() {}
+
+func (x *MessageOneofSingleField) ProtoReflect() protoreflect.Message {
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[10]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageOneofSingleField.ProtoReflect.Descriptor instead.
+func (*MessageOneofSingleField) Descriptor() ([]byte, []int) {
+	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{10}
+}
+
+func (x *MessageOneofSingleField) GetStrField() string {
+	if x != nil {
+		return x.StrField
+	}
+	return ""
+}
+
+func (x *MessageOneofSingleField) GetBoolField() bool {
+	if x != nil {
+		return x.BoolField
+	}
+	return false
+}
+
+type MessageOneofMultipleFields struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	StrField      string                 `protobuf:"bytes,1,opt,name=str_field,json=strField,proto3" json:"str_field,omitempty"`
+	BoolField     bool                   `protobuf:"varint,2,opt,name=bool_field,json=boolField,proto3" json:"bool_field,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *MessageOneofMultipleFields) Reset() {
+	*x = MessageOneofMultipleFields{}
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[11]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *MessageOneofMultipleFields) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageOneofMultipleFields) ProtoMessage() {}
+
+func (x *MessageOneofMultipleFields) ProtoReflect() protoreflect.Message {
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[11]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageOneofMultipleFields.ProtoReflect.Descriptor instead.
+func (*MessageOneofMultipleFields) Descriptor() ([]byte, []int) {
+	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{11}
+}
+
+func (x *MessageOneofMultipleFields) GetStrField() string {
+	if x != nil {
+		return x.StrField
+	}
+	return ""
+}
+
+func (x *MessageOneofMultipleFields) GetBoolField() bool {
+	if x != nil {
+		return x.BoolField
+	}
+	return false
+}
+
+type MessageOneofMultipleFieldsRequired struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	StrField      string                 `protobuf:"bytes,1,opt,name=str_field,json=strField,proto3" json:"str_field,omitempty"`
+	BoolField     bool                   `protobuf:"varint,2,opt,name=bool_field,json=boolField,proto3" json:"bool_field,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *MessageOneofMultipleFieldsRequired) Reset() {
+	*x = MessageOneofMultipleFieldsRequired{}
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[12]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *MessageOneofMultipleFieldsRequired) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageOneofMultipleFieldsRequired) ProtoMessage() {}
+
+func (x *MessageOneofMultipleFieldsRequired) ProtoReflect() protoreflect.Message {
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[12]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageOneofMultipleFieldsRequired.ProtoReflect.Descriptor instead.
+func (*MessageOneofMultipleFieldsRequired) Descriptor() ([]byte, []int) {
+	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{12}
+}
+
+func (x *MessageOneofMultipleFieldsRequired) GetStrField() string {
+	if x != nil {
+		return x.StrField
+	}
+	return ""
+}
+
+func (x *MessageOneofMultipleFieldsRequired) GetBoolField() bool {
+	if x != nil {
+		return x.BoolField
+	}
+	return false
+}
+
 type MessageNone_NoneMsg struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	unknownFields protoimpl.UnknownFields
@@ -507,7 +663,7 @@ type MessageNone_NoneMsg struct {
 
 func (x *MessageNone_NoneMsg) Reset() {
 	*x = MessageNone_NoneMsg{}
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[10]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[13]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -519,7 +675,7 @@ func (x *MessageNone_NoneMsg) String() string {
 func (*MessageNone_NoneMsg) ProtoMessage() {}
 
 func (x *MessageNone_NoneMsg) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[10]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[13]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -564,7 +720,26 @@ const file_buf_validate_conformance_cases_messages_proto_rawDesc = "" +
 	"\x14MessageRequiredOneof\x12C\n" +
 	"\x03val\x18\x01 \x01(\v2'.buf.validate.conformance.cases.TestMsgB\x06\xbaH\x03\xc8\x01\x01H\x00R\x03valB\f\n" +
 	"\x03one\x12\x05\xbaH\x02\b\x01\"\x15\n" +
-	"\x13MessageWith3dInsideB\xa4\x02\n" +
+	"\x13MessageWith3dInside\"g\n" +
+	"\x17MessageOneofSingleField\x12\x1b\n" +
+	"\tstr_field\x18\x01 \x01(\tR\bstrField\x12\x1d\n" +
+	"\n" +
+	"bool_field\x18\x02 \x01(\bR\tboolField:\x10\xbaH\r\"\v\n" +
+	"\tstr_field\"v\n" +
+	"\x1aMessageOneofMultipleFields\x12\x1b\n" +
+	"\tstr_field\x18\x01 \x01(\tR\bstrField\x12\x1d\n" +
+	"\n" +
+	"bool_field\x18\x02 \x01(\bR\tboolField:\x1c\xbaH\x19\"\x17\n" +
+	"\tstr_field\n" +
+	"\n" +
+	"bool_field\"\x80\x01\n" +
+	"\"MessageOneofMultipleFieldsRequired\x12\x1b\n" +
+	"\tstr_field\x18\x01 \x01(\tR\bstrField\x12\x1d\n" +
+	"\n" +
+	"bool_field\x18\x02 \x01(\bR\tboolField:\x1e\xbaH\x1b\"\x19\n" +
+	"\tstr_field\n" +
+	"\n" +
+	"bool_field\x10\x01B\xa4\x02\n" +
 	"\"com.buf.validate.conformance.casesB\rMessagesProtoP\x01ZSgithub.com/bufbuild/protovalidate/tools/internal/gen/buf/validate/conformance/cases\xa2\x02\x04BVCC\xaa\x02\x1eBuf.Validate.Conformance.Cases\xca\x02\x1eBuf\\Validate\\Conformance\\Cases\xe2\x02*Buf\\Validate\\Conformance\\Cases\\GPBMetadata\xea\x02!Buf::Validate::Conformance::Casesb\x06proto3"
 
 var (
@@ -579,26 +754,29 @@ func file_buf_validate_conformance_cases_messages_proto_rawDescGZIP() []byte {
 	return file_buf_validate_conformance_cases_messages_proto_rawDescData
 }
 
-var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 11)
+var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 14)
 var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
-	(*TestMsg)(nil),                    // 0: buf.validate.conformance.cases.TestMsg
-	(*MessageNone)(nil),                // 1: buf.validate.conformance.cases.MessageNone
-	(*MessageDisabled)(nil),            // 2: buf.validate.conformance.cases.MessageDisabled
-	(*Message)(nil),                    // 3: buf.validate.conformance.cases.Message
-	(*MessageCrossPackage)(nil),        // 4: buf.validate.conformance.cases.MessageCrossPackage
-	(*MessageSkip)(nil),                // 5: buf.validate.conformance.cases.MessageSkip
-	(*MessageRequired)(nil),            // 6: buf.validate.conformance.cases.MessageRequired
-	(*MessageRequiredButOptional)(nil), // 7: buf.validate.conformance.cases.MessageRequiredButOptional
-	(*MessageRequiredOneof)(nil),       // 8: buf.validate.conformance.cases.MessageRequiredOneof
-	(*MessageWith3DInside)(nil),        // 9: buf.validate.conformance.cases.MessageWith3dInside
-	(*MessageNone_NoneMsg)(nil),        // 10: buf.validate.conformance.cases.MessageNone.NoneMsg
-	(*other_package.Embed)(nil),        // 11: buf.validate.conformance.cases.other_package.Embed
+	(*TestMsg)(nil),                            // 0: buf.validate.conformance.cases.TestMsg
+	(*MessageNone)(nil),                        // 1: buf.validate.conformance.cases.MessageNone
+	(*MessageDisabled)(nil),                    // 2: buf.validate.conformance.cases.MessageDisabled
+	(*Message)(nil),                            // 3: buf.validate.conformance.cases.Message
+	(*MessageCrossPackage)(nil),                // 4: buf.validate.conformance.cases.MessageCrossPackage
+	(*MessageSkip)(nil),                        // 5: buf.validate.conformance.cases.MessageSkip
+	(*MessageRequired)(nil),                    // 6: buf.validate.conformance.cases.MessageRequired
+	(*MessageRequiredButOptional)(nil),         // 7: buf.validate.conformance.cases.MessageRequiredButOptional
+	(*MessageRequiredOneof)(nil),               // 8: buf.validate.conformance.cases.MessageRequiredOneof
+	(*MessageWith3DInside)(nil),                // 9: buf.validate.conformance.cases.MessageWith3dInside
+	(*MessageOneofSingleField)(nil),            // 10: buf.validate.conformance.cases.MessageOneofSingleField
+	(*MessageOneofMultipleFields)(nil),         // 11: buf.validate.conformance.cases.MessageOneofMultipleFields
+	(*MessageOneofMultipleFieldsRequired)(nil), // 12: buf.validate.conformance.cases.MessageOneofMultipleFieldsRequired
+	(*MessageNone_NoneMsg)(nil),                // 13: buf.validate.conformance.cases.MessageNone.NoneMsg
+	(*other_package.Embed)(nil),                // 14: buf.validate.conformance.cases.other_package.Embed
 }
 var file_buf_validate_conformance_cases_messages_proto_depIdxs = []int32{
 	0,  // 0: buf.validate.conformance.cases.TestMsg.nested:type_name -> buf.validate.conformance.cases.TestMsg
-	10, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
+	13, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
 	0,  // 2: buf.validate.conformance.cases.Message.val:type_name -> buf.validate.conformance.cases.TestMsg
-	11, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
+	14, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
 	0,  // 4: buf.validate.conformance.cases.MessageSkip.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 5: buf.validate.conformance.cases.MessageRequired.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 6: buf.validate.conformance.cases.MessageRequiredButOptional.val:type_name -> buf.validate.conformance.cases.TestMsg
@@ -625,7 +803,7 @@ func file_buf_validate_conformance_cases_messages_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_buf_validate_conformance_cases_messages_proto_rawDesc), len(file_buf_validate_conformance_cases_messages_proto_rawDesc)),
 			NumEnums:      0,
-			NumMessages:   11,
+			NumMessages:   14,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/tools/internal/gen/buf/validate/validate.pb.go b/tools/internal/gen/buf/validate/validate.pb.go
index bee4a016..e2368783 100644
--- a/tools/internal/gen/buf/validate/validate.pb.go
+++ b/tools/internal/gen/buf/validate/validate.pb.go
@@ -423,7 +423,22 @@ type MessageRules struct {
 	//	}
 	//
 	// ```
-	Cel           []*Rule `protobuf:"bytes,3,rep,name=cel" json:"cel,omitempty"`
+	Cel []*Rule `protobuf:"bytes,3,rep,name=cel" json:"cel,omitempty"`
+	// `oneof` is a repeated field of type MessageOneofRule that specifies a list of fields
+	// of which exactly one can be present. If `required` is also specified, then exactly one
+	// of the specified fields _must_ be present.
+	//
+	// ```proto
+	//
+	//	message MyMessage {
+	//	  // Only one of 'field1' or 'field2' _can_ be present in this message.
+	//	  option (buf.validate.message).oneof = { fields: ["field1", "field2"] };
+	//	  // Only one of 'field3' or 'field4' _must_ be present in this message.
+	//	  option (buf.validate.message).oneof = { fields: ["field3", "field4"], required: true };
+	//	}
+	//
+	// ```
+	Oneof         []*MessageOneofRule `protobuf:"bytes,4,rep,name=oneof" json:"oneof,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
@@ -472,6 +487,65 @@ func (x *MessageRules) GetCel() []*Rule {
 	return nil
 }
 
+func (x *MessageRules) GetOneof() []*MessageOneofRule {
+	if x != nil {
+		return x.Oneof
+	}
+	return nil
+}
+
+type MessageOneofRule struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Fields        []string               `protobuf:"bytes,1,rep,name=fields" json:"fields,omitempty"`
+	Required      *bool                  `protobuf:"varint,2,opt,name=required" json:"required,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *MessageOneofRule) Reset() {
+	*x = MessageOneofRule{}
+	mi := &file_buf_validate_validate_proto_msgTypes[2]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *MessageOneofRule) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageOneofRule) ProtoMessage() {}
+
+func (x *MessageOneofRule) ProtoReflect() protoreflect.Message {
+	mi := &file_buf_validate_validate_proto_msgTypes[2]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageOneofRule.ProtoReflect.Descriptor instead.
+func (*MessageOneofRule) Descriptor() ([]byte, []int) {
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{2}
+}
+
+func (x *MessageOneofRule) GetFields() []string {
+	if x != nil {
+		return x.Fields
+	}
+	return nil
+}
+
+func (x *MessageOneofRule) GetRequired() bool {
+	if x != nil && x.Required != nil {
+		return *x.Required
+	}
+	return false
+}
+
 // The `OneofRules` message type enables you to manage rules for
 // oneof fields in your protobuf messages.
 type OneofRules struct {
@@ -502,7 +576,7 @@ type OneofRules struct {
 
 func (x *OneofRules) Reset() {
 	*x = OneofRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[2]
+	mi := &file_buf_validate_validate_proto_msgTypes[3]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -514,7 +588,7 @@ func (x *OneofRules) String() string {
 func (*OneofRules) ProtoMessage() {}
 
 func (x *OneofRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[2]
+	mi := &file_buf_validate_validate_proto_msgTypes[3]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -527,7 +601,7 @@ func (x *OneofRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OneofRules.ProtoReflect.Descriptor instead.
 func (*OneofRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{2}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{3}
 }
 
 func (x *OneofRules) GetRequired() bool {
@@ -626,7 +700,7 @@ type FieldRules struct {
 
 func (x *FieldRules) Reset() {
 	*x = FieldRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[3]
+	mi := &file_buf_validate_validate_proto_msgTypes[4]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -638,7 +712,7 @@ func (x *FieldRules) String() string {
 func (*FieldRules) ProtoMessage() {}
 
 func (x *FieldRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[3]
+	mi := &file_buf_validate_validate_proto_msgTypes[4]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -651,7 +725,7 @@ func (x *FieldRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use FieldRules.ProtoReflect.Descriptor instead.
 func (*FieldRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{3}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{4}
 }
 
 func (x *FieldRules) GetCel() []*Rule {
@@ -1031,7 +1105,7 @@ type PredefinedRules struct {
 
 func (x *PredefinedRules) Reset() {
 	*x = PredefinedRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[4]
+	mi := &file_buf_validate_validate_proto_msgTypes[5]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1043,7 +1117,7 @@ func (x *PredefinedRules) String() string {
 func (*PredefinedRules) ProtoMessage() {}
 
 func (x *PredefinedRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[4]
+	mi := &file_buf_validate_validate_proto_msgTypes[5]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1056,7 +1130,7 @@ func (x *PredefinedRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use PredefinedRules.ProtoReflect.Descriptor instead.
 func (*PredefinedRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{4}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{5}
 }
 
 func (x *PredefinedRules) GetCel() []*Rule {
@@ -1143,7 +1217,7 @@ type FloatRules struct {
 
 func (x *FloatRules) Reset() {
 	*x = FloatRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[5]
+	mi := &file_buf_validate_validate_proto_msgTypes[6]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1155,7 +1229,7 @@ func (x *FloatRules) String() string {
 func (*FloatRules) ProtoMessage() {}
 
 func (x *FloatRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[5]
+	mi := &file_buf_validate_validate_proto_msgTypes[6]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1168,7 +1242,7 @@ func (x *FloatRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use FloatRules.ProtoReflect.Descriptor instead.
 func (*FloatRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{5}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{6}
 }
 
 func (x *FloatRules) GetConst() float32 {
@@ -1429,7 +1503,7 @@ type DoubleRules struct {
 
 func (x *DoubleRules) Reset() {
 	*x = DoubleRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[6]
+	mi := &file_buf_validate_validate_proto_msgTypes[7]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1441,7 +1515,7 @@ func (x *DoubleRules) String() string {
 func (*DoubleRules) ProtoMessage() {}
 
 func (x *DoubleRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[6]
+	mi := &file_buf_validate_validate_proto_msgTypes[7]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1454,7 +1528,7 @@ func (x *DoubleRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use DoubleRules.ProtoReflect.Descriptor instead.
 func (*DoubleRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{6}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{7}
 }
 
 func (x *DoubleRules) GetConst() float64 {
@@ -1712,7 +1786,7 @@ type Int32Rules struct {
 
 func (x *Int32Rules) Reset() {
 	*x = Int32Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[7]
+	mi := &file_buf_validate_validate_proto_msgTypes[8]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -1724,7 +1798,7 @@ func (x *Int32Rules) String() string {
 func (*Int32Rules) ProtoMessage() {}
 
 func (x *Int32Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[7]
+	mi := &file_buf_validate_validate_proto_msgTypes[8]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -1737,7 +1811,7 @@ func (x *Int32Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Int32Rules.ProtoReflect.Descriptor instead.
 func (*Int32Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{7}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{8}
 }
 
 func (x *Int32Rules) GetConst() int32 {
@@ -1988,7 +2062,7 @@ type Int64Rules struct {
 
 func (x *Int64Rules) Reset() {
 	*x = Int64Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[8]
+	mi := &file_buf_validate_validate_proto_msgTypes[9]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2000,7 +2074,7 @@ func (x *Int64Rules) String() string {
 func (*Int64Rules) ProtoMessage() {}
 
 func (x *Int64Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[8]
+	mi := &file_buf_validate_validate_proto_msgTypes[9]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2013,7 +2087,7 @@ func (x *Int64Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Int64Rules.ProtoReflect.Descriptor instead.
 func (*Int64Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{8}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{9}
 }
 
 func (x *Int64Rules) GetConst() int64 {
@@ -2264,7 +2338,7 @@ type UInt32Rules struct {
 
 func (x *UInt32Rules) Reset() {
 	*x = UInt32Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[9]
+	mi := &file_buf_validate_validate_proto_msgTypes[10]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2276,7 +2350,7 @@ func (x *UInt32Rules) String() string {
 func (*UInt32Rules) ProtoMessage() {}
 
 func (x *UInt32Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[9]
+	mi := &file_buf_validate_validate_proto_msgTypes[10]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2289,7 +2363,7 @@ func (x *UInt32Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use UInt32Rules.ProtoReflect.Descriptor instead.
 func (*UInt32Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{9}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{10}
 }
 
 func (x *UInt32Rules) GetConst() uint32 {
@@ -2540,7 +2614,7 @@ type UInt64Rules struct {
 
 func (x *UInt64Rules) Reset() {
 	*x = UInt64Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[10]
+	mi := &file_buf_validate_validate_proto_msgTypes[11]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2552,7 +2626,7 @@ func (x *UInt64Rules) String() string {
 func (*UInt64Rules) ProtoMessage() {}
 
 func (x *UInt64Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[10]
+	mi := &file_buf_validate_validate_proto_msgTypes[11]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2565,7 +2639,7 @@ func (x *UInt64Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use UInt64Rules.ProtoReflect.Descriptor instead.
 func (*UInt64Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{10}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{11}
 }
 
 func (x *UInt64Rules) GetConst() uint64 {
@@ -2815,7 +2889,7 @@ type SInt32Rules struct {
 
 func (x *SInt32Rules) Reset() {
 	*x = SInt32Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[11]
+	mi := &file_buf_validate_validate_proto_msgTypes[12]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -2827,7 +2901,7 @@ func (x *SInt32Rules) String() string {
 func (*SInt32Rules) ProtoMessage() {}
 
 func (x *SInt32Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[11]
+	mi := &file_buf_validate_validate_proto_msgTypes[12]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -2840,7 +2914,7 @@ func (x *SInt32Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use SInt32Rules.ProtoReflect.Descriptor instead.
 func (*SInt32Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{11}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{12}
 }
 
 func (x *SInt32Rules) GetConst() int32 {
@@ -3090,7 +3164,7 @@ type SInt64Rules struct {
 
 func (x *SInt64Rules) Reset() {
 	*x = SInt64Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[12]
+	mi := &file_buf_validate_validate_proto_msgTypes[13]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -3102,7 +3176,7 @@ func (x *SInt64Rules) String() string {
 func (*SInt64Rules) ProtoMessage() {}
 
 func (x *SInt64Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[12]
+	mi := &file_buf_validate_validate_proto_msgTypes[13]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -3115,7 +3189,7 @@ func (x *SInt64Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use SInt64Rules.ProtoReflect.Descriptor instead.
 func (*SInt64Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{12}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{13}
 }
 
 func (x *SInt64Rules) GetConst() int64 {
@@ -3365,7 +3439,7 @@ type Fixed32Rules struct {
 
 func (x *Fixed32Rules) Reset() {
 	*x = Fixed32Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[13]
+	mi := &file_buf_validate_validate_proto_msgTypes[14]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -3377,7 +3451,7 @@ func (x *Fixed32Rules) String() string {
 func (*Fixed32Rules) ProtoMessage() {}
 
 func (x *Fixed32Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[13]
+	mi := &file_buf_validate_validate_proto_msgTypes[14]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -3390,7 +3464,7 @@ func (x *Fixed32Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Fixed32Rules.ProtoReflect.Descriptor instead.
 func (*Fixed32Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{13}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{14}
 }
 
 func (x *Fixed32Rules) GetConst() uint32 {
@@ -3640,7 +3714,7 @@ type Fixed64Rules struct {
 
 func (x *Fixed64Rules) Reset() {
 	*x = Fixed64Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[14]
+	mi := &file_buf_validate_validate_proto_msgTypes[15]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -3652,7 +3726,7 @@ func (x *Fixed64Rules) String() string {
 func (*Fixed64Rules) ProtoMessage() {}
 
 func (x *Fixed64Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[14]
+	mi := &file_buf_validate_validate_proto_msgTypes[15]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -3665,7 +3739,7 @@ func (x *Fixed64Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Fixed64Rules.ProtoReflect.Descriptor instead.
 func (*Fixed64Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{14}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{15}
 }
 
 func (x *Fixed64Rules) GetConst() uint64 {
@@ -3915,7 +3989,7 @@ type SFixed32Rules struct {
 
 func (x *SFixed32Rules) Reset() {
 	*x = SFixed32Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[15]
+	mi := &file_buf_validate_validate_proto_msgTypes[16]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -3927,7 +4001,7 @@ func (x *SFixed32Rules) String() string {
 func (*SFixed32Rules) ProtoMessage() {}
 
 func (x *SFixed32Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[15]
+	mi := &file_buf_validate_validate_proto_msgTypes[16]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -3940,7 +4014,7 @@ func (x *SFixed32Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use SFixed32Rules.ProtoReflect.Descriptor instead.
 func (*SFixed32Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{15}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{16}
 }
 
 func (x *SFixed32Rules) GetConst() int32 {
@@ -4190,7 +4264,7 @@ type SFixed64Rules struct {
 
 func (x *SFixed64Rules) Reset() {
 	*x = SFixed64Rules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[16]
+	mi := &file_buf_validate_validate_proto_msgTypes[17]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -4202,7 +4276,7 @@ func (x *SFixed64Rules) String() string {
 func (*SFixed64Rules) ProtoMessage() {}
 
 func (x *SFixed64Rules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[16]
+	mi := &file_buf_validate_validate_proto_msgTypes[17]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -4215,7 +4289,7 @@ func (x *SFixed64Rules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use SFixed64Rules.ProtoReflect.Descriptor instead.
 func (*SFixed64Rules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{16}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{17}
 }
 
 func (x *SFixed64Rules) GetConst() int64 {
@@ -4430,7 +4504,7 @@ type BoolRules struct {
 
 func (x *BoolRules) Reset() {
 	*x = BoolRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[17]
+	mi := &file_buf_validate_validate_proto_msgTypes[18]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -4442,7 +4516,7 @@ func (x *BoolRules) String() string {
 func (*BoolRules) ProtoMessage() {}
 
 func (x *BoolRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[17]
+	mi := &file_buf_validate_validate_proto_msgTypes[18]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -4455,7 +4529,7 @@ func (x *BoolRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use BoolRules.ProtoReflect.Descriptor instead.
 func (*BoolRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{17}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{18}
 }
 
 func (x *BoolRules) GetConst() bool {
@@ -4722,7 +4796,7 @@ type StringRules struct {
 
 func (x *StringRules) Reset() {
 	*x = StringRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[18]
+	mi := &file_buf_validate_validate_proto_msgTypes[19]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -4734,7 +4808,7 @@ func (x *StringRules) String() string {
 func (*StringRules) ProtoMessage() {}
 
 func (x *StringRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[18]
+	mi := &file_buf_validate_validate_proto_msgTypes[19]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -4747,7 +4821,7 @@ func (x *StringRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use StringRules.ProtoReflect.Descriptor instead.
 func (*StringRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{18}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{19}
 }
 
 func (x *StringRules) GetConst() string {
@@ -5590,7 +5664,7 @@ type BytesRules struct {
 
 func (x *BytesRules) Reset() {
 	*x = BytesRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[19]
+	mi := &file_buf_validate_validate_proto_msgTypes[20]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -5602,7 +5676,7 @@ func (x *BytesRules) String() string {
 func (*BytesRules) ProtoMessage() {}
 
 func (x *BytesRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[19]
+	mi := &file_buf_validate_validate_proto_msgTypes[20]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -5615,7 +5689,7 @@ func (x *BytesRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use BytesRules.ProtoReflect.Descriptor instead.
 func (*BytesRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{19}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{20}
 }
 
 func (x *BytesRules) GetConst() []byte {
@@ -5886,7 +5960,7 @@ type EnumRules struct {
 
 func (x *EnumRules) Reset() {
 	*x = EnumRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[20]
+	mi := &file_buf_validate_validate_proto_msgTypes[21]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -5898,7 +5972,7 @@ func (x *EnumRules) String() string {
 func (*EnumRules) ProtoMessage() {}
 
 func (x *EnumRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[20]
+	mi := &file_buf_validate_validate_proto_msgTypes[21]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -5911,7 +5985,7 @@ func (x *EnumRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use EnumRules.ProtoReflect.Descriptor instead.
 func (*EnumRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{20}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{21}
 }
 
 func (x *EnumRules) GetConst() int32 {
@@ -6021,7 +6095,7 @@ type RepeatedRules struct {
 
 func (x *RepeatedRules) Reset() {
 	*x = RepeatedRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[21]
+	mi := &file_buf_validate_validate_proto_msgTypes[22]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -6033,7 +6107,7 @@ func (x *RepeatedRules) String() string {
 func (*RepeatedRules) ProtoMessage() {}
 
 func (x *RepeatedRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[21]
+	mi := &file_buf_validate_validate_proto_msgTypes[22]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -6046,7 +6120,7 @@ func (x *RepeatedRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RepeatedRules.ProtoReflect.Descriptor instead.
 func (*RepeatedRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{21}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{22}
 }
 
 func (x *RepeatedRules) GetMinItems() uint64 {
@@ -6151,7 +6225,7 @@ type MapRules struct {
 
 func (x *MapRules) Reset() {
 	*x = MapRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[22]
+	mi := &file_buf_validate_validate_proto_msgTypes[23]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -6163,7 +6237,7 @@ func (x *MapRules) String() string {
 func (*MapRules) ProtoMessage() {}
 
 func (x *MapRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[22]
+	mi := &file_buf_validate_validate_proto_msgTypes[23]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -6176,7 +6250,7 @@ func (x *MapRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use MapRules.ProtoReflect.Descriptor instead.
 func (*MapRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{22}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{23}
 }
 
 func (x *MapRules) GetMinPairs() uint64 {
@@ -6244,7 +6318,7 @@ type AnyRules struct {
 
 func (x *AnyRules) Reset() {
 	*x = AnyRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[23]
+	mi := &file_buf_validate_validate_proto_msgTypes[24]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -6256,7 +6330,7 @@ func (x *AnyRules) String() string {
 func (*AnyRules) ProtoMessage() {}
 
 func (x *AnyRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[23]
+	mi := &file_buf_validate_validate_proto_msgTypes[24]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -6269,7 +6343,7 @@ func (x *AnyRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use AnyRules.ProtoReflect.Descriptor instead.
 func (*AnyRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{23}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{24}
 }
 
 func (x *AnyRules) GetIn() []string {
@@ -6361,7 +6435,7 @@ type DurationRules struct {
 
 func (x *DurationRules) Reset() {
 	*x = DurationRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[24]
+	mi := &file_buf_validate_validate_proto_msgTypes[25]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -6373,7 +6447,7 @@ func (x *DurationRules) String() string {
 func (*DurationRules) ProtoMessage() {}
 
 func (x *DurationRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[24]
+	mi := &file_buf_validate_validate_proto_msgTypes[25]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -6386,7 +6460,7 @@ func (x *DurationRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use DurationRules.ProtoReflect.Descriptor instead.
 func (*DurationRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{24}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{25}
 }
 
 func (x *DurationRules) GetConst() *durationpb.Duration {
@@ -6622,7 +6696,7 @@ type TimestampRules struct {
 
 func (x *TimestampRules) Reset() {
 	*x = TimestampRules{}
-	mi := &file_buf_validate_validate_proto_msgTypes[25]
+	mi := &file_buf_validate_validate_proto_msgTypes[26]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -6634,7 +6708,7 @@ func (x *TimestampRules) String() string {
 func (*TimestampRules) ProtoMessage() {}
 
 func (x *TimestampRules) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[25]
+	mi := &file_buf_validate_validate_proto_msgTypes[26]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -6647,7 +6721,7 @@ func (x *TimestampRules) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use TimestampRules.ProtoReflect.Descriptor instead.
 func (*TimestampRules) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{25}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{26}
 }
 
 func (x *TimestampRules) GetConst() *timestamppb.Timestamp {
@@ -6876,7 +6950,7 @@ type Violations struct {
 
 func (x *Violations) Reset() {
 	*x = Violations{}
-	mi := &file_buf_validate_validate_proto_msgTypes[26]
+	mi := &file_buf_validate_validate_proto_msgTypes[27]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -6888,7 +6962,7 @@ func (x *Violations) String() string {
 func (*Violations) ProtoMessage() {}
 
 func (x *Violations) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[26]
+	mi := &file_buf_validate_validate_proto_msgTypes[27]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -6901,7 +6975,7 @@ func (x *Violations) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Violations.ProtoReflect.Descriptor instead.
 func (*Violations) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{26}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{27}
 }
 
 func (x *Violations) GetViolations() []*Violation {
@@ -7032,7 +7106,7 @@ type Violation struct {
 
 func (x *Violation) Reset() {
 	*x = Violation{}
-	mi := &file_buf_validate_validate_proto_msgTypes[27]
+	mi := &file_buf_validate_validate_proto_msgTypes[28]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -7044,7 +7118,7 @@ func (x *Violation) String() string {
 func (*Violation) ProtoMessage() {}
 
 func (x *Violation) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[27]
+	mi := &file_buf_validate_validate_proto_msgTypes[28]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -7057,7 +7131,7 @@ func (x *Violation) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Violation.ProtoReflect.Descriptor instead.
 func (*Violation) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{27}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{28}
 }
 
 func (x *Violation) GetField() *FieldPath {
@@ -7109,7 +7183,7 @@ type FieldPath struct {
 
 func (x *FieldPath) Reset() {
 	*x = FieldPath{}
-	mi := &file_buf_validate_validate_proto_msgTypes[28]
+	mi := &file_buf_validate_validate_proto_msgTypes[29]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -7121,7 +7195,7 @@ func (x *FieldPath) String() string {
 func (*FieldPath) ProtoMessage() {}
 
 func (x *FieldPath) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[28]
+	mi := &file_buf_validate_validate_proto_msgTypes[29]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -7134,7 +7208,7 @@ func (x *FieldPath) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use FieldPath.ProtoReflect.Descriptor instead.
 func (*FieldPath) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{28}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{29}
 }
 
 func (x *FieldPath) GetElements() []*FieldPathElement {
@@ -7190,7 +7264,7 @@ type FieldPathElement struct {
 
 func (x *FieldPathElement) Reset() {
 	*x = FieldPathElement{}
-	mi := &file_buf_validate_validate_proto_msgTypes[29]
+	mi := &file_buf_validate_validate_proto_msgTypes[30]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -7202,7 +7276,7 @@ func (x *FieldPathElement) String() string {
 func (*FieldPathElement) ProtoMessage() {}
 
 func (x *FieldPathElement) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_validate_proto_msgTypes[29]
+	mi := &file_buf_validate_validate_proto_msgTypes[30]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -7215,7 +7289,7 @@ func (x *FieldPathElement) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use FieldPathElement.ProtoReflect.Descriptor instead.
 func (*FieldPathElement) Descriptor() ([]byte, []int) {
-	return file_buf_validate_validate_proto_rawDescGZIP(), []int{29}
+	return file_buf_validate_validate_proto_rawDescGZIP(), []int{30}
 }
 
 func (x *FieldPathElement) GetFieldNumber() int32 {
@@ -7437,10 +7511,14 @@ const file_buf_validate_validate_proto_rawDesc = "" +
 	"\amessage\x18\x02 \x01(\tR\amessage\x12\x1e\n" +
 	"\n" +
 	"expression\x18\x03 \x01(\tR\n" +
-	"expression\"P\n" +
+	"expression\"\x86\x01\n" +
 	"\fMessageRules\x12\x1a\n" +
 	"\bdisabled\x18\x01 \x01(\bR\bdisabled\x12$\n" +
-	"\x03cel\x18\x03 \x03(\v2\x12.buf.validate.RuleR\x03cel\"(\n" +
+	"\x03cel\x18\x03 \x03(\v2\x12.buf.validate.RuleR\x03cel\x124\n" +
+	"\x05oneof\x18\x04 \x03(\v2\x1e.buf.validate.MessageOneofRuleR\x05oneof\"F\n" +
+	"\x10MessageOneofRule\x12\x16\n" +
+	"\x06fields\x18\x01 \x03(\tR\x06fields\x12\x1a\n" +
+	"\brequired\x18\x02 \x01(\bR\brequired\"(\n" +
 	"\n" +
 	"OneofRules\x12\x1a\n" +
 	"\brequired\x18\x01 \x01(\bR\brequired\"\xfd\t\n" +
@@ -8412,112 +8490,114 @@ func file_buf_validate_validate_proto_rawDescGZIP() []byte {
 }
 
 var file_buf_validate_validate_proto_enumTypes = make([]protoimpl.EnumInfo, 2)
-var file_buf_validate_validate_proto_msgTypes = make([]protoimpl.MessageInfo, 30)
+var file_buf_validate_validate_proto_msgTypes = make([]protoimpl.MessageInfo, 31)
 var file_buf_validate_validate_proto_goTypes = []any{
 	(Ignore)(0),                                 // 0: buf.validate.Ignore
 	(KnownRegex)(0),                             // 1: buf.validate.KnownRegex
 	(*Rule)(nil),                                // 2: buf.validate.Rule
 	(*MessageRules)(nil),                        // 3: buf.validate.MessageRules
-	(*OneofRules)(nil),                          // 4: buf.validate.OneofRules
-	(*FieldRules)(nil),                          // 5: buf.validate.FieldRules
-	(*PredefinedRules)(nil),                     // 6: buf.validate.PredefinedRules
-	(*FloatRules)(nil),                          // 7: buf.validate.FloatRules
-	(*DoubleRules)(nil),                         // 8: buf.validate.DoubleRules
-	(*Int32Rules)(nil),                          // 9: buf.validate.Int32Rules
-	(*Int64Rules)(nil),                          // 10: buf.validate.Int64Rules
-	(*UInt32Rules)(nil),                         // 11: buf.validate.UInt32Rules
-	(*UInt64Rules)(nil),                         // 12: buf.validate.UInt64Rules
-	(*SInt32Rules)(nil),                         // 13: buf.validate.SInt32Rules
-	(*SInt64Rules)(nil),                         // 14: buf.validate.SInt64Rules
-	(*Fixed32Rules)(nil),                        // 15: buf.validate.Fixed32Rules
-	(*Fixed64Rules)(nil),                        // 16: buf.validate.Fixed64Rules
-	(*SFixed32Rules)(nil),                       // 17: buf.validate.SFixed32Rules
-	(*SFixed64Rules)(nil),                       // 18: buf.validate.SFixed64Rules
-	(*BoolRules)(nil),                           // 19: buf.validate.BoolRules
-	(*StringRules)(nil),                         // 20: buf.validate.StringRules
-	(*BytesRules)(nil),                          // 21: buf.validate.BytesRules
-	(*EnumRules)(nil),                           // 22: buf.validate.EnumRules
-	(*RepeatedRules)(nil),                       // 23: buf.validate.RepeatedRules
-	(*MapRules)(nil),                            // 24: buf.validate.MapRules
-	(*AnyRules)(nil),                            // 25: buf.validate.AnyRules
-	(*DurationRules)(nil),                       // 26: buf.validate.DurationRules
-	(*TimestampRules)(nil),                      // 27: buf.validate.TimestampRules
-	(*Violations)(nil),                          // 28: buf.validate.Violations
-	(*Violation)(nil),                           // 29: buf.validate.Violation
-	(*FieldPath)(nil),                           // 30: buf.validate.FieldPath
-	(*FieldPathElement)(nil),                    // 31: buf.validate.FieldPathElement
-	(*durationpb.Duration)(nil),                 // 32: google.protobuf.Duration
-	(*timestamppb.Timestamp)(nil),               // 33: google.protobuf.Timestamp
-	(descriptorpb.FieldDescriptorProto_Type)(0), // 34: google.protobuf.FieldDescriptorProto.Type
-	(*descriptorpb.MessageOptions)(nil),         // 35: google.protobuf.MessageOptions
-	(*descriptorpb.OneofOptions)(nil),           // 36: google.protobuf.OneofOptions
-	(*descriptorpb.FieldOptions)(nil),           // 37: google.protobuf.FieldOptions
+	(*MessageOneofRule)(nil),                    // 4: buf.validate.MessageOneofRule
+	(*OneofRules)(nil),                          // 5: buf.validate.OneofRules
+	(*FieldRules)(nil),                          // 6: buf.validate.FieldRules
+	(*PredefinedRules)(nil),                     // 7: buf.validate.PredefinedRules
+	(*FloatRules)(nil),                          // 8: buf.validate.FloatRules
+	(*DoubleRules)(nil),                         // 9: buf.validate.DoubleRules
+	(*Int32Rules)(nil),                          // 10: buf.validate.Int32Rules
+	(*Int64Rules)(nil),                          // 11: buf.validate.Int64Rules
+	(*UInt32Rules)(nil),                         // 12: buf.validate.UInt32Rules
+	(*UInt64Rules)(nil),                         // 13: buf.validate.UInt64Rules
+	(*SInt32Rules)(nil),                         // 14: buf.validate.SInt32Rules
+	(*SInt64Rules)(nil),                         // 15: buf.validate.SInt64Rules
+	(*Fixed32Rules)(nil),                        // 16: buf.validate.Fixed32Rules
+	(*Fixed64Rules)(nil),                        // 17: buf.validate.Fixed64Rules
+	(*SFixed32Rules)(nil),                       // 18: buf.validate.SFixed32Rules
+	(*SFixed64Rules)(nil),                       // 19: buf.validate.SFixed64Rules
+	(*BoolRules)(nil),                           // 20: buf.validate.BoolRules
+	(*StringRules)(nil),                         // 21: buf.validate.StringRules
+	(*BytesRules)(nil),                          // 22: buf.validate.BytesRules
+	(*EnumRules)(nil),                           // 23: buf.validate.EnumRules
+	(*RepeatedRules)(nil),                       // 24: buf.validate.RepeatedRules
+	(*MapRules)(nil),                            // 25: buf.validate.MapRules
+	(*AnyRules)(nil),                            // 26: buf.validate.AnyRules
+	(*DurationRules)(nil),                       // 27: buf.validate.DurationRules
+	(*TimestampRules)(nil),                      // 28: buf.validate.TimestampRules
+	(*Violations)(nil),                          // 29: buf.validate.Violations
+	(*Violation)(nil),                           // 30: buf.validate.Violation
+	(*FieldPath)(nil),                           // 31: buf.validate.FieldPath
+	(*FieldPathElement)(nil),                    // 32: buf.validate.FieldPathElement
+	(*durationpb.Duration)(nil),                 // 33: google.protobuf.Duration
+	(*timestamppb.Timestamp)(nil),               // 34: google.protobuf.Timestamp
+	(descriptorpb.FieldDescriptorProto_Type)(0), // 35: google.protobuf.FieldDescriptorProto.Type
+	(*descriptorpb.MessageOptions)(nil),         // 36: google.protobuf.MessageOptions
+	(*descriptorpb.OneofOptions)(nil),           // 37: google.protobuf.OneofOptions
+	(*descriptorpb.FieldOptions)(nil),           // 38: google.protobuf.FieldOptions
 }
 var file_buf_validate_validate_proto_depIdxs = []int32{
 	2,  // 0: buf.validate.MessageRules.cel:type_name -> buf.validate.Rule
-	2,  // 1: buf.validate.FieldRules.cel:type_name -> buf.validate.Rule
-	0,  // 2: buf.validate.FieldRules.ignore:type_name -> buf.validate.Ignore
-	7,  // 3: buf.validate.FieldRules.float:type_name -> buf.validate.FloatRules
-	8,  // 4: buf.validate.FieldRules.double:type_name -> buf.validate.DoubleRules
-	9,  // 5: buf.validate.FieldRules.int32:type_name -> buf.validate.Int32Rules
-	10, // 6: buf.validate.FieldRules.int64:type_name -> buf.validate.Int64Rules
-	11, // 7: buf.validate.FieldRules.uint32:type_name -> buf.validate.UInt32Rules
-	12, // 8: buf.validate.FieldRules.uint64:type_name -> buf.validate.UInt64Rules
-	13, // 9: buf.validate.FieldRules.sint32:type_name -> buf.validate.SInt32Rules
-	14, // 10: buf.validate.FieldRules.sint64:type_name -> buf.validate.SInt64Rules
-	15, // 11: buf.validate.FieldRules.fixed32:type_name -> buf.validate.Fixed32Rules
-	16, // 12: buf.validate.FieldRules.fixed64:type_name -> buf.validate.Fixed64Rules
-	17, // 13: buf.validate.FieldRules.sfixed32:type_name -> buf.validate.SFixed32Rules
-	18, // 14: buf.validate.FieldRules.sfixed64:type_name -> buf.validate.SFixed64Rules
-	19, // 15: buf.validate.FieldRules.bool:type_name -> buf.validate.BoolRules
-	20, // 16: buf.validate.FieldRules.string:type_name -> buf.validate.StringRules
-	21, // 17: buf.validate.FieldRules.bytes:type_name -> buf.validate.BytesRules
-	22, // 18: buf.validate.FieldRules.enum:type_name -> buf.validate.EnumRules
-	23, // 19: buf.validate.FieldRules.repeated:type_name -> buf.validate.RepeatedRules
-	24, // 20: buf.validate.FieldRules.map:type_name -> buf.validate.MapRules
-	25, // 21: buf.validate.FieldRules.any:type_name -> buf.validate.AnyRules
-	26, // 22: buf.validate.FieldRules.duration:type_name -> buf.validate.DurationRules
-	27, // 23: buf.validate.FieldRules.timestamp:type_name -> buf.validate.TimestampRules
-	2,  // 24: buf.validate.PredefinedRules.cel:type_name -> buf.validate.Rule
-	1,  // 25: buf.validate.StringRules.well_known_regex:type_name -> buf.validate.KnownRegex
-	5,  // 26: buf.validate.RepeatedRules.items:type_name -> buf.validate.FieldRules
-	5,  // 27: buf.validate.MapRules.keys:type_name -> buf.validate.FieldRules
-	5,  // 28: buf.validate.MapRules.values:type_name -> buf.validate.FieldRules
-	32, // 29: buf.validate.DurationRules.const:type_name -> google.protobuf.Duration
-	32, // 30: buf.validate.DurationRules.lt:type_name -> google.protobuf.Duration
-	32, // 31: buf.validate.DurationRules.lte:type_name -> google.protobuf.Duration
-	32, // 32: buf.validate.DurationRules.gt:type_name -> google.protobuf.Duration
-	32, // 33: buf.validate.DurationRules.gte:type_name -> google.protobuf.Duration
-	32, // 34: buf.validate.DurationRules.in:type_name -> google.protobuf.Duration
-	32, // 35: buf.validate.DurationRules.not_in:type_name -> google.protobuf.Duration
-	32, // 36: buf.validate.DurationRules.example:type_name -> google.protobuf.Duration
-	33, // 37: buf.validate.TimestampRules.const:type_name -> google.protobuf.Timestamp
-	33, // 38: buf.validate.TimestampRules.lt:type_name -> google.protobuf.Timestamp
-	33, // 39: buf.validate.TimestampRules.lte:type_name -> google.protobuf.Timestamp
-	33, // 40: buf.validate.TimestampRules.gt:type_name -> google.protobuf.Timestamp
-	33, // 41: buf.validate.TimestampRules.gte:type_name -> google.protobuf.Timestamp
-	32, // 42: buf.validate.TimestampRules.within:type_name -> google.protobuf.Duration
-	33, // 43: buf.validate.TimestampRules.example:type_name -> google.protobuf.Timestamp
-	29, // 44: buf.validate.Violations.violations:type_name -> buf.validate.Violation
-	30, // 45: buf.validate.Violation.field:type_name -> buf.validate.FieldPath
-	30, // 46: buf.validate.Violation.rule:type_name -> buf.validate.FieldPath
-	31, // 47: buf.validate.FieldPath.elements:type_name -> buf.validate.FieldPathElement
-	34, // 48: buf.validate.FieldPathElement.field_type:type_name -> google.protobuf.FieldDescriptorProto.Type
-	34, // 49: buf.validate.FieldPathElement.key_type:type_name -> google.protobuf.FieldDescriptorProto.Type
-	34, // 50: buf.validate.FieldPathElement.value_type:type_name -> google.protobuf.FieldDescriptorProto.Type
-	35, // 51: buf.validate.message:extendee -> google.protobuf.MessageOptions
-	36, // 52: buf.validate.oneof:extendee -> google.protobuf.OneofOptions
-	37, // 53: buf.validate.field:extendee -> google.protobuf.FieldOptions
-	37, // 54: buf.validate.predefined:extendee -> google.protobuf.FieldOptions
-	3,  // 55: buf.validate.message:type_name -> buf.validate.MessageRules
-	4,  // 56: buf.validate.oneof:type_name -> buf.validate.OneofRules
-	5,  // 57: buf.validate.field:type_name -> buf.validate.FieldRules
-	6,  // 58: buf.validate.predefined:type_name -> buf.validate.PredefinedRules
-	59, // [59:59] is the sub-list for method output_type
-	59, // [59:59] is the sub-list for method input_type
-	55, // [55:59] is the sub-list for extension type_name
-	51, // [51:55] is the sub-list for extension extendee
-	0,  // [0:51] is the sub-list for field type_name
+	4,  // 1: buf.validate.MessageRules.oneof:type_name -> buf.validate.MessageOneofRule
+	2,  // 2: buf.validate.FieldRules.cel:type_name -> buf.validate.Rule
+	0,  // 3: buf.validate.FieldRules.ignore:type_name -> buf.validate.Ignore
+	8,  // 4: buf.validate.FieldRules.float:type_name -> buf.validate.FloatRules
+	9,  // 5: buf.validate.FieldRules.double:type_name -> buf.validate.DoubleRules
+	10, // 6: buf.validate.FieldRules.int32:type_name -> buf.validate.Int32Rules
+	11, // 7: buf.validate.FieldRules.int64:type_name -> buf.validate.Int64Rules
+	12, // 8: buf.validate.FieldRules.uint32:type_name -> buf.validate.UInt32Rules
+	13, // 9: buf.validate.FieldRules.uint64:type_name -> buf.validate.UInt64Rules
+	14, // 10: buf.validate.FieldRules.sint32:type_name -> buf.validate.SInt32Rules
+	15, // 11: buf.validate.FieldRules.sint64:type_name -> buf.validate.SInt64Rules
+	16, // 12: buf.validate.FieldRules.fixed32:type_name -> buf.validate.Fixed32Rules
+	17, // 13: buf.validate.FieldRules.fixed64:type_name -> buf.validate.Fixed64Rules
+	18, // 14: buf.validate.FieldRules.sfixed32:type_name -> buf.validate.SFixed32Rules
+	19, // 15: buf.validate.FieldRules.sfixed64:type_name -> buf.validate.SFixed64Rules
+	20, // 16: buf.validate.FieldRules.bool:type_name -> buf.validate.BoolRules
+	21, // 17: buf.validate.FieldRules.string:type_name -> buf.validate.StringRules
+	22, // 18: buf.validate.FieldRules.bytes:type_name -> buf.validate.BytesRules
+	23, // 19: buf.validate.FieldRules.enum:type_name -> buf.validate.EnumRules
+	24, // 20: buf.validate.FieldRules.repeated:type_name -> buf.validate.RepeatedRules
+	25, // 21: buf.validate.FieldRules.map:type_name -> buf.validate.MapRules
+	26, // 22: buf.validate.FieldRules.any:type_name -> buf.validate.AnyRules
+	27, // 23: buf.validate.FieldRules.duration:type_name -> buf.validate.DurationRules
+	28, // 24: buf.validate.FieldRules.timestamp:type_name -> buf.validate.TimestampRules
+	2,  // 25: buf.validate.PredefinedRules.cel:type_name -> buf.validate.Rule
+	1,  // 26: buf.validate.StringRules.well_known_regex:type_name -> buf.validate.KnownRegex
+	6,  // 27: buf.validate.RepeatedRules.items:type_name -> buf.validate.FieldRules
+	6,  // 28: buf.validate.MapRules.keys:type_name -> buf.validate.FieldRules
+	6,  // 29: buf.validate.MapRules.values:type_name -> buf.validate.FieldRules
+	33, // 30: buf.validate.DurationRules.const:type_name -> google.protobuf.Duration
+	33, // 31: buf.validate.DurationRules.lt:type_name -> google.protobuf.Duration
+	33, // 32: buf.validate.DurationRules.lte:type_name -> google.protobuf.Duration
+	33, // 33: buf.validate.DurationRules.gt:type_name -> google.protobuf.Duration
+	33, // 34: buf.validate.DurationRules.gte:type_name -> google.protobuf.Duration
+	33, // 35: buf.validate.DurationRules.in:type_name -> google.protobuf.Duration
+	33, // 36: buf.validate.DurationRules.not_in:type_name -> google.protobuf.Duration
+	33, // 37: buf.validate.DurationRules.example:type_name -> google.protobuf.Duration
+	34, // 38: buf.validate.TimestampRules.const:type_name -> google.protobuf.Timestamp
+	34, // 39: buf.validate.TimestampRules.lt:type_name -> google.protobuf.Timestamp
+	34, // 40: buf.validate.TimestampRules.lte:type_name -> google.protobuf.Timestamp
+	34, // 41: buf.validate.TimestampRules.gt:type_name -> google.protobuf.Timestamp
+	34, // 42: buf.validate.TimestampRules.gte:type_name -> google.protobuf.Timestamp
+	33, // 43: buf.validate.TimestampRules.within:type_name -> google.protobuf.Duration
+	34, // 44: buf.validate.TimestampRules.example:type_name -> google.protobuf.Timestamp
+	30, // 45: buf.validate.Violations.violations:type_name -> buf.validate.Violation
+	31, // 46: buf.validate.Violation.field:type_name -> buf.validate.FieldPath
+	31, // 47: buf.validate.Violation.rule:type_name -> buf.validate.FieldPath
+	32, // 48: buf.validate.FieldPath.elements:type_name -> buf.validate.FieldPathElement
+	35, // 49: buf.validate.FieldPathElement.field_type:type_name -> google.protobuf.FieldDescriptorProto.Type
+	35, // 50: buf.validate.FieldPathElement.key_type:type_name -> google.protobuf.FieldDescriptorProto.Type
+	35, // 51: buf.validate.FieldPathElement.value_type:type_name -> google.protobuf.FieldDescriptorProto.Type
+	36, // 52: buf.validate.message:extendee -> google.protobuf.MessageOptions
+	37, // 53: buf.validate.oneof:extendee -> google.protobuf.OneofOptions
+	38, // 54: buf.validate.field:extendee -> google.protobuf.FieldOptions
+	38, // 55: buf.validate.predefined:extendee -> google.protobuf.FieldOptions
+	3,  // 56: buf.validate.message:type_name -> buf.validate.MessageRules
+	5,  // 57: buf.validate.oneof:type_name -> buf.validate.OneofRules
+	6,  // 58: buf.validate.field:type_name -> buf.validate.FieldRules
+	7,  // 59: buf.validate.predefined:type_name -> buf.validate.PredefinedRules
+	60, // [60:60] is the sub-list for method output_type
+	60, // [60:60] is the sub-list for method input_type
+	56, // [56:60] is the sub-list for extension type_name
+	52, // [52:56] is the sub-list for extension extendee
+	0,  // [0:52] is the sub-list for field type_name
 }
 
 func init() { file_buf_validate_validate_proto_init() }
@@ -8525,7 +8605,7 @@ func file_buf_validate_validate_proto_init() {
 	if File_buf_validate_validate_proto != nil {
 		return
 	}
-	file_buf_validate_validate_proto_msgTypes[3].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[4].OneofWrappers = []any{
 		(*FieldRules_Float)(nil),
 		(*FieldRules_Double)(nil),
 		(*FieldRules_Int32)(nil),
@@ -8548,79 +8628,79 @@ func file_buf_validate_validate_proto_init() {
 		(*FieldRules_Duration)(nil),
 		(*FieldRules_Timestamp)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[5].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[6].OneofWrappers = []any{
 		(*FloatRules_Lt)(nil),
 		(*FloatRules_Lte)(nil),
 		(*FloatRules_Gt)(nil),
 		(*FloatRules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[6].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[7].OneofWrappers = []any{
 		(*DoubleRules_Lt)(nil),
 		(*DoubleRules_Lte)(nil),
 		(*DoubleRules_Gt)(nil),
 		(*DoubleRules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[7].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[8].OneofWrappers = []any{
 		(*Int32Rules_Lt)(nil),
 		(*Int32Rules_Lte)(nil),
 		(*Int32Rules_Gt)(nil),
 		(*Int32Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[8].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[9].OneofWrappers = []any{
 		(*Int64Rules_Lt)(nil),
 		(*Int64Rules_Lte)(nil),
 		(*Int64Rules_Gt)(nil),
 		(*Int64Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[9].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[10].OneofWrappers = []any{
 		(*UInt32Rules_Lt)(nil),
 		(*UInt32Rules_Lte)(nil),
 		(*UInt32Rules_Gt)(nil),
 		(*UInt32Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[10].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[11].OneofWrappers = []any{
 		(*UInt64Rules_Lt)(nil),
 		(*UInt64Rules_Lte)(nil),
 		(*UInt64Rules_Gt)(nil),
 		(*UInt64Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[11].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[12].OneofWrappers = []any{
 		(*SInt32Rules_Lt)(nil),
 		(*SInt32Rules_Lte)(nil),
 		(*SInt32Rules_Gt)(nil),
 		(*SInt32Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[12].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[13].OneofWrappers = []any{
 		(*SInt64Rules_Lt)(nil),
 		(*SInt64Rules_Lte)(nil),
 		(*SInt64Rules_Gt)(nil),
 		(*SInt64Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[13].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[14].OneofWrappers = []any{
 		(*Fixed32Rules_Lt)(nil),
 		(*Fixed32Rules_Lte)(nil),
 		(*Fixed32Rules_Gt)(nil),
 		(*Fixed32Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[14].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[15].OneofWrappers = []any{
 		(*Fixed64Rules_Lt)(nil),
 		(*Fixed64Rules_Lte)(nil),
 		(*Fixed64Rules_Gt)(nil),
 		(*Fixed64Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[15].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[16].OneofWrappers = []any{
 		(*SFixed32Rules_Lt)(nil),
 		(*SFixed32Rules_Lte)(nil),
 		(*SFixed32Rules_Gt)(nil),
 		(*SFixed32Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[16].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[17].OneofWrappers = []any{
 		(*SFixed64Rules_Lt)(nil),
 		(*SFixed64Rules_Lte)(nil),
 		(*SFixed64Rules_Gt)(nil),
 		(*SFixed64Rules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[18].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[19].OneofWrappers = []any{
 		(*StringRules_Email)(nil),
 		(*StringRules_Hostname)(nil),
 		(*StringRules_Ip)(nil),
@@ -8640,18 +8720,18 @@ func file_buf_validate_validate_proto_init() {
 		(*StringRules_HostAndPort)(nil),
 		(*StringRules_WellKnownRegex)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[19].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[20].OneofWrappers = []any{
 		(*BytesRules_Ip)(nil),
 		(*BytesRules_Ipv4)(nil),
 		(*BytesRules_Ipv6)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[24].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[25].OneofWrappers = []any{
 		(*DurationRules_Lt)(nil),
 		(*DurationRules_Lte)(nil),
 		(*DurationRules_Gt)(nil),
 		(*DurationRules_Gte)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[25].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[26].OneofWrappers = []any{
 		(*TimestampRules_Lt)(nil),
 		(*TimestampRules_Lte)(nil),
 		(*TimestampRules_LtNow)(nil),
@@ -8659,7 +8739,7 @@ func file_buf_validate_validate_proto_init() {
 		(*TimestampRules_Gte)(nil),
 		(*TimestampRules_GtNow)(nil),
 	}
-	file_buf_validate_validate_proto_msgTypes[29].OneofWrappers = []any{
+	file_buf_validate_validate_proto_msgTypes[30].OneofWrappers = []any{
 		(*FieldPathElement_Index)(nil),
 		(*FieldPathElement_BoolKey)(nil),
 		(*FieldPathElement_IntKey)(nil),
@@ -8672,7 +8752,7 @@ func file_buf_validate_validate_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_buf_validate_validate_proto_rawDesc), len(file_buf_validate_validate_proto_rawDesc)),
 			NumEnums:      2,
-			NumMessages:   30,
+			NumMessages:   31,
 			NumExtensions: 4,
 			NumServices:   0,
 		},
diff --git a/tools/protovalidate-conformance/internal/cases/cases_message.go b/tools/protovalidate-conformance/internal/cases/cases_message.go
index 62ae1924..0d5ae0c6 100644
--- a/tools/protovalidate-conformance/internal/cases/cases_message.go
+++ b/tools/protovalidate-conformance/internal/cases/cases_message.go
@@ -155,5 +155,36 @@ func messageSuite() suites.Suite {
 				},
 			),
 		},
+		"oneof/single-field/valid": {
+			// BoolField is not part of the oneof, so it can be set on this message
+			Message:  &cases.MessageOneofSingleField{StrField: "test", BoolField: true},
+			Expected: results.Success(true),
+		},
+		"oneof/two-fields/valid": {
+			Message:  &cases.MessageOneofMultipleFields{StrField: "test"},
+			Expected: results.Success(true),
+		},
+		"oneof/two-fields/invalid": {
+			Message: &cases.MessageOneofMultipleFields{StrField: "test", BoolField: true},
+			Expected: results.Violations(
+				&validate.Violation{
+					RuleId:  proto.String("message.oneof"),
+					Message: proto.String("only one of ['str_field', 'bool_field'] can be set"),
+				},
+			),
+		},
+		"oneof/multiple-fields/required/valid": {
+			Message:  &cases.MessageOneofMultipleFieldsRequired{StrField: "test"},
+			Expected: results.Success(true),
+		},
+		"oneof/multiple-fields/required/invalid": {
+			Message: &cases.MessageOneofMultipleFieldsRequired{},
+			Expected: results.Violations(
+				&validate.Violation{
+					RuleId:  proto.String("message.oneof"),
+					Message: proto.String("one of ['str_field', 'bool_field'] must be set"),
+				},
+			),
+		},
 	}
 }

From 4e0ef3549e6b0921e444cdda5a999d73e07178bf Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Tue, 10 Jun 2025 20:05:47 -0400
Subject: [PATCH 2/9] Format

---
 .../validate/conformance/cases/messages.proto | 31 +++++++++++++------
 .../protovalidate/buf/validate/validate.proto |  4 +--
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
index 40e6ff64..e4f96ef0 100644
--- a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
+++ b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
@@ -60,19 +60,32 @@ message MessageRequiredOneof {
 message MessageWith3dInside {}
 
 message MessageOneofSingleField {
-   option (buf.validate.message).oneof = { fields: ["str_field"] };
-   string str_field = 1;
-   bool bool_field = 2;
+  option (buf.validate.message).oneof = {
+    fields: ["str_field"]
+  };
+  string str_field = 1;
+  bool bool_field = 2;
 }
 
 message MessageOneofMultipleFields {
-   option (buf.validate.message).oneof = { fields: ["str_field", "bool_field"] };
-   string str_field = 1;
-   bool bool_field = 2;
+  option (buf.validate.message).oneof = {
+    fields: [
+      "str_field",
+      "bool_field"
+    ]
+  };
+  string str_field = 1;
+  bool bool_field = 2;
 }
 
 message MessageOneofMultipleFieldsRequired {
-   option (buf.validate.message).oneof = { fields: ["str_field", "bool_field"], required: true };
-   string str_field = 1;
-   bool bool_field = 2;
+  option (buf.validate.message).oneof = {
+    fields: [
+      "str_field",
+      "bool_field"
+    ]
+    required: true
+  };
+  string str_field = 1;
+  bool bool_field = 2;
 }
diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index 5765396d..0d819c1c 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -145,9 +145,9 @@ message MessageRules {
   //
   // ```proto
   // message MyMessage {
-  //   // Only one of 'field1' or 'field2' _can_ be present in this message. 
+  //   // Only one of 'field1' or 'field2' _can_ be present in this message.
   //   option (buf.validate.message).oneof = { fields: ["field1", "field2"] };
-  //   // Only one of 'field3' or 'field4' _must_ be present in this message. 
+  //   // Only one of 'field3' or 'field4' _must_ be present in this message.
   //   option (buf.validate.message).oneof = { fields: ["field3", "field4"], required: true };
   // }
   // ```

From 74982402fc59c9cd06cc743c619c4e66b913649f Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 09:19:32 -0400
Subject: [PATCH 3/9] Feedback

---
 .../validate/conformance/cases/messages.proto |  7 ++
 .../validate/conformance/cases/messages.pb.go | 67 ++++++++++++++++---
 .../internal/cases/cases_message.go           |  8 ++-
 3 files changed, 71 insertions(+), 11 deletions(-)

diff --git a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
index e4f96ef0..d04671ad 100644
--- a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
+++ b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
@@ -89,3 +89,10 @@ message MessageOneofMultipleFieldsRequired {
   string str_field = 1;
   bool bool_field = 2;
 }
+
+message MessageOneofUnknownFieldName {
+  option (buf.validate.message).oneof = {
+    fields: ["xxx"]
+  };
+  string str_field = 1;
+}
diff --git a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
index 3e40533c..8eff7fd0 100644
--- a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
+++ b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
@@ -655,6 +655,50 @@ func (x *MessageOneofMultipleFieldsRequired) GetBoolField() bool {
 	return false
 }
 
+type MessageOneofUnknownFieldName struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	StrField      string                 `protobuf:"bytes,1,opt,name=str_field,json=strField,proto3" json:"str_field,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *MessageOneofUnknownFieldName) Reset() {
+	*x = MessageOneofUnknownFieldName{}
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[13]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *MessageOneofUnknownFieldName) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageOneofUnknownFieldName) ProtoMessage() {}
+
+func (x *MessageOneofUnknownFieldName) ProtoReflect() protoreflect.Message {
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[13]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageOneofUnknownFieldName.ProtoReflect.Descriptor instead.
+func (*MessageOneofUnknownFieldName) Descriptor() ([]byte, []int) {
+	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{13}
+}
+
+func (x *MessageOneofUnknownFieldName) GetStrField() string {
+	if x != nil {
+		return x.StrField
+	}
+	return ""
+}
+
 type MessageNone_NoneMsg struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	unknownFields protoimpl.UnknownFields
@@ -663,7 +707,7 @@ type MessageNone_NoneMsg struct {
 
 func (x *MessageNone_NoneMsg) Reset() {
 	*x = MessageNone_NoneMsg{}
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[13]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -675,7 +719,7 @@ func (x *MessageNone_NoneMsg) String() string {
 func (*MessageNone_NoneMsg) ProtoMessage() {}
 
 func (x *MessageNone_NoneMsg) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[13]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -739,7 +783,11 @@ const file_buf_validate_conformance_cases_messages_proto_rawDesc = "" +
 	"bool_field\x18\x02 \x01(\bR\tboolField:\x1e\xbaH\x1b\"\x19\n" +
 	"\tstr_field\n" +
 	"\n" +
-	"bool_field\x10\x01B\xa4\x02\n" +
+	"bool_field\x10\x01\"G\n" +
+	"\x1cMessageOneofUnknownFieldName\x12\x1b\n" +
+	"\tstr_field\x18\x01 \x01(\tR\bstrField:\n" +
+	"\xbaH\a\"\x05\n" +
+	"\x03xxxB\xa4\x02\n" +
 	"\"com.buf.validate.conformance.casesB\rMessagesProtoP\x01ZSgithub.com/bufbuild/protovalidate/tools/internal/gen/buf/validate/conformance/cases\xa2\x02\x04BVCC\xaa\x02\x1eBuf.Validate.Conformance.Cases\xca\x02\x1eBuf\\Validate\\Conformance\\Cases\xe2\x02*Buf\\Validate\\Conformance\\Cases\\GPBMetadata\xea\x02!Buf::Validate::Conformance::Casesb\x06proto3"
 
 var (
@@ -754,7 +802,7 @@ func file_buf_validate_conformance_cases_messages_proto_rawDescGZIP() []byte {
 	return file_buf_validate_conformance_cases_messages_proto_rawDescData
 }
 
-var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 14)
+var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 15)
 var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
 	(*TestMsg)(nil),                            // 0: buf.validate.conformance.cases.TestMsg
 	(*MessageNone)(nil),                        // 1: buf.validate.conformance.cases.MessageNone
@@ -769,14 +817,15 @@ var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
 	(*MessageOneofSingleField)(nil),            // 10: buf.validate.conformance.cases.MessageOneofSingleField
 	(*MessageOneofMultipleFields)(nil),         // 11: buf.validate.conformance.cases.MessageOneofMultipleFields
 	(*MessageOneofMultipleFieldsRequired)(nil), // 12: buf.validate.conformance.cases.MessageOneofMultipleFieldsRequired
-	(*MessageNone_NoneMsg)(nil),                // 13: buf.validate.conformance.cases.MessageNone.NoneMsg
-	(*other_package.Embed)(nil),                // 14: buf.validate.conformance.cases.other_package.Embed
+	(*MessageOneofUnknownFieldName)(nil),       // 13: buf.validate.conformance.cases.MessageOneofUnknownFieldName
+	(*MessageNone_NoneMsg)(nil),                // 14: buf.validate.conformance.cases.MessageNone.NoneMsg
+	(*other_package.Embed)(nil),                // 15: buf.validate.conformance.cases.other_package.Embed
 }
 var file_buf_validate_conformance_cases_messages_proto_depIdxs = []int32{
 	0,  // 0: buf.validate.conformance.cases.TestMsg.nested:type_name -> buf.validate.conformance.cases.TestMsg
-	13, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
+	14, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
 	0,  // 2: buf.validate.conformance.cases.Message.val:type_name -> buf.validate.conformance.cases.TestMsg
-	14, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
+	15, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
 	0,  // 4: buf.validate.conformance.cases.MessageSkip.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 5: buf.validate.conformance.cases.MessageRequired.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 6: buf.validate.conformance.cases.MessageRequiredButOptional.val:type_name -> buf.validate.conformance.cases.TestMsg
@@ -803,7 +852,7 @@ func file_buf_validate_conformance_cases_messages_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_buf_validate_conformance_cases_messages_proto_rawDesc), len(file_buf_validate_conformance_cases_messages_proto_rawDesc)),
 			NumEnums:      0,
-			NumMessages:   14,
+			NumMessages:   15,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/tools/protovalidate-conformance/internal/cases/cases_message.go b/tools/protovalidate-conformance/internal/cases/cases_message.go
index 0d5ae0c6..1e962f54 100644
--- a/tools/protovalidate-conformance/internal/cases/cases_message.go
+++ b/tools/protovalidate-conformance/internal/cases/cases_message.go
@@ -169,7 +169,7 @@ func messageSuite() suites.Suite {
 			Expected: results.Violations(
 				&validate.Violation{
 					RuleId:  proto.String("message.oneof"),
-					Message: proto.String("only one of ['str_field', 'bool_field'] can be set"),
+					Message: proto.String("only one of str_field, bool_field can be set"),
 				},
 			),
 		},
@@ -182,9 +182,13 @@ func messageSuite() suites.Suite {
 			Expected: results.Violations(
 				&validate.Violation{
 					RuleId:  proto.String("message.oneof"),
-					Message: proto.String("one of ['str_field', 'bool_field'] must be set"),
+					Message: proto.String("one of str_field, bool_field must be set"),
 				},
 			),
 		},
+		"oneof/unknown-field/invalid": {
+			Message:  &cases.MessageOneofUnknownFieldName{},
+			Expected: results.CompilationError("field not found in message"),
+		},
 	}
 }

From 1b4d5d422956f0d0cdfd50980920c1d2b8e4dbc9 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 09:52:57 -0400
Subject: [PATCH 4/9] Feedback

---
 proto/protovalidate/buf/validate/validate.proto           | 8 ++++++--
 tools/internal/gen/buf/validate/validate.pb.go            | 8 ++++++--
 .../internal/cases/cases_message.go                       | 2 +-
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index 0d819c1c..511c5fad 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -145,10 +145,14 @@ message MessageRules {
   //
   // ```proto
   // message MyMessage {
-  //   // Only one of 'field1' or 'field2' _can_ be present in this message.
+  //   // Only one of `field1` or `field2` _can_ be present in this message.
   //   option (buf.validate.message).oneof = { fields: ["field1", "field2"] };
-  //   // Only one of 'field3' or 'field4' _must_ be present in this message.
+  //   // Only one of `field3` or `field4` _must_ be present in this message.
   //   option (buf.validate.message).oneof = { fields: ["field3", "field4"], required: true };
+  //   string field1 = 1;
+  //   bytes field2 = 2;
+  //   bool field3 = 3;
+  //   int32 field4 = 4;
   // }
   // ```
   repeated MessageOneofRule oneof = 4;
diff --git a/tools/internal/gen/buf/validate/validate.pb.go b/tools/internal/gen/buf/validate/validate.pb.go
index e2368783..1b7b315b 100644
--- a/tools/internal/gen/buf/validate/validate.pb.go
+++ b/tools/internal/gen/buf/validate/validate.pb.go
@@ -431,10 +431,14 @@ type MessageRules struct {
 	// ```proto
 	//
 	//	message MyMessage {
-	//	  // Only one of 'field1' or 'field2' _can_ be present in this message.
+	//	  // Only one of `field1` or `field2` _can_ be present in this message.
 	//	  option (buf.validate.message).oneof = { fields: ["field1", "field2"] };
-	//	  // Only one of 'field3' or 'field4' _must_ be present in this message.
+	//	  // Only one of `field3` or `field4` _must_ be present in this message.
 	//	  option (buf.validate.message).oneof = { fields: ["field3", "field4"], required: true };
+	//	  string field1 = 1;
+	//	  bytes field2 = 2;
+	//	  bool field3 = 3;
+	//	  int32 field4 = 4;
 	//	}
 	//
 	// ```
diff --git a/tools/protovalidate-conformance/internal/cases/cases_message.go b/tools/protovalidate-conformance/internal/cases/cases_message.go
index 1e962f54..1d7faad7 100644
--- a/tools/protovalidate-conformance/internal/cases/cases_message.go
+++ b/tools/protovalidate-conformance/internal/cases/cases_message.go
@@ -188,7 +188,7 @@ func messageSuite() suites.Suite {
 		},
 		"oneof/unknown-field/invalid": {
 			Message:  &cases.MessageOneofUnknownFieldName{},
-			Expected: results.CompilationError("field not found in message"),
+			Expected: results.CompilationError("field xxx not found in message buf.validate.conformance.cases.MessageOneofUnknownFieldName"),
 		},
 	}
 }

From 57e344bea389d9effddb0f36157399de2b664d5f Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 12:17:17 -0400
Subject: [PATCH 5/9] Feedback

---
 .../validate/conformance/cases/messages.proto |  7 ++
 .../protovalidate/buf/validate/validate.proto |  3 +
 .../validate/conformance/cases/messages.pb.go | 65 ++++++++++++++++---
 .../internal/gen/buf/validate/validate.pb.go  |  9 ++-
 .../internal/cases/cases_message.go           |  4 ++
 5 files changed, 76 insertions(+), 12 deletions(-)

diff --git a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
index d04671ad..d04a495b 100644
--- a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
+++ b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
@@ -96,3 +96,10 @@ message MessageOneofUnknownFieldName {
   };
   string str_field = 1;
 }
+
+message MessageOneofNoFields {
+  option (buf.validate.message).oneof = {
+    fields: []
+  };
+  string str_field = 1;
+}
diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index 511c5fad..0b306763 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -159,7 +159,10 @@ message MessageRules {
 }
 
 message MessageOneofRule {
+  // A list of field names to include in the oneof. All field names must be 
+  // defined in the message.
   repeated string fields = 1;
+  // If true, one of the fields specified _must_ be set.
   optional bool required = 2;
 }
 
diff --git a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
index 8eff7fd0..8be04cff 100644
--- a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
+++ b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
@@ -699,6 +699,50 @@ func (x *MessageOneofUnknownFieldName) GetStrField() string {
 	return ""
 }
 
+type MessageOneofNoFields struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	StrField      string                 `protobuf:"bytes,1,opt,name=str_field,json=strField,proto3" json:"str_field,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *MessageOneofNoFields) Reset() {
+	*x = MessageOneofNoFields{}
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *MessageOneofNoFields) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*MessageOneofNoFields) ProtoMessage() {}
+
+func (x *MessageOneofNoFields) ProtoReflect() protoreflect.Message {
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use MessageOneofNoFields.ProtoReflect.Descriptor instead.
+func (*MessageOneofNoFields) Descriptor() ([]byte, []int) {
+	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{14}
+}
+
+func (x *MessageOneofNoFields) GetStrField() string {
+	if x != nil {
+		return x.StrField
+	}
+	return ""
+}
+
 type MessageNone_NoneMsg struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	unknownFields protoimpl.UnknownFields
@@ -707,7 +751,7 @@ type MessageNone_NoneMsg struct {
 
 func (x *MessageNone_NoneMsg) Reset() {
 	*x = MessageNone_NoneMsg{}
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[15]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -719,7 +763,7 @@ func (x *MessageNone_NoneMsg) String() string {
 func (*MessageNone_NoneMsg) ProtoMessage() {}
 
 func (x *MessageNone_NoneMsg) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[15]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -787,7 +831,9 @@ const file_buf_validate_conformance_cases_messages_proto_rawDesc = "" +
 	"\x1cMessageOneofUnknownFieldName\x12\x1b\n" +
 	"\tstr_field\x18\x01 \x01(\tR\bstrField:\n" +
 	"\xbaH\a\"\x05\n" +
-	"\x03xxxB\xa4\x02\n" +
+	"\x03xxx\":\n" +
+	"\x14MessageOneofNoFields\x12\x1b\n" +
+	"\tstr_field\x18\x01 \x01(\tR\bstrField:\x05\xbaH\x02\"\x00B\xa4\x02\n" +
 	"\"com.buf.validate.conformance.casesB\rMessagesProtoP\x01ZSgithub.com/bufbuild/protovalidate/tools/internal/gen/buf/validate/conformance/cases\xa2\x02\x04BVCC\xaa\x02\x1eBuf.Validate.Conformance.Cases\xca\x02\x1eBuf\\Validate\\Conformance\\Cases\xe2\x02*Buf\\Validate\\Conformance\\Cases\\GPBMetadata\xea\x02!Buf::Validate::Conformance::Casesb\x06proto3"
 
 var (
@@ -802,7 +848,7 @@ func file_buf_validate_conformance_cases_messages_proto_rawDescGZIP() []byte {
 	return file_buf_validate_conformance_cases_messages_proto_rawDescData
 }
 
-var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 15)
+var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 16)
 var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
 	(*TestMsg)(nil),                            // 0: buf.validate.conformance.cases.TestMsg
 	(*MessageNone)(nil),                        // 1: buf.validate.conformance.cases.MessageNone
@@ -818,14 +864,15 @@ var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
 	(*MessageOneofMultipleFields)(nil),         // 11: buf.validate.conformance.cases.MessageOneofMultipleFields
 	(*MessageOneofMultipleFieldsRequired)(nil), // 12: buf.validate.conformance.cases.MessageOneofMultipleFieldsRequired
 	(*MessageOneofUnknownFieldName)(nil),       // 13: buf.validate.conformance.cases.MessageOneofUnknownFieldName
-	(*MessageNone_NoneMsg)(nil),                // 14: buf.validate.conformance.cases.MessageNone.NoneMsg
-	(*other_package.Embed)(nil),                // 15: buf.validate.conformance.cases.other_package.Embed
+	(*MessageOneofNoFields)(nil),               // 14: buf.validate.conformance.cases.MessageOneofNoFields
+	(*MessageNone_NoneMsg)(nil),                // 15: buf.validate.conformance.cases.MessageNone.NoneMsg
+	(*other_package.Embed)(nil),                // 16: buf.validate.conformance.cases.other_package.Embed
 }
 var file_buf_validate_conformance_cases_messages_proto_depIdxs = []int32{
 	0,  // 0: buf.validate.conformance.cases.TestMsg.nested:type_name -> buf.validate.conformance.cases.TestMsg
-	14, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
+	15, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
 	0,  // 2: buf.validate.conformance.cases.Message.val:type_name -> buf.validate.conformance.cases.TestMsg
-	15, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
+	16, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
 	0,  // 4: buf.validate.conformance.cases.MessageSkip.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 5: buf.validate.conformance.cases.MessageRequired.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 6: buf.validate.conformance.cases.MessageRequiredButOptional.val:type_name -> buf.validate.conformance.cases.TestMsg
@@ -852,7 +899,7 @@ func file_buf_validate_conformance_cases_messages_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_buf_validate_conformance_cases_messages_proto_rawDesc), len(file_buf_validate_conformance_cases_messages_proto_rawDesc)),
 			NumEnums:      0,
-			NumMessages:   15,
+			NumMessages:   16,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/tools/internal/gen/buf/validate/validate.pb.go b/tools/internal/gen/buf/validate/validate.pb.go
index 1b7b315b..c4cd3c85 100644
--- a/tools/internal/gen/buf/validate/validate.pb.go
+++ b/tools/internal/gen/buf/validate/validate.pb.go
@@ -499,9 +499,12 @@ func (x *MessageRules) GetOneof() []*MessageOneofRule {
 }
 
 type MessageOneofRule struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	Fields        []string               `protobuf:"bytes,1,rep,name=fields" json:"fields,omitempty"`
-	Required      *bool                  `protobuf:"varint,2,opt,name=required" json:"required,omitempty"`
+	state protoimpl.MessageState `protogen:"open.v1"`
+	// A list of field names to include in the oneof. All field names must be
+	// defined in the message.
+	Fields []string `protobuf:"bytes,1,rep,name=fields" json:"fields,omitempty"`
+	// If true, one of the fields specified _must_ be set.
+	Required      *bool `protobuf:"varint,2,opt,name=required" json:"required,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
diff --git a/tools/protovalidate-conformance/internal/cases/cases_message.go b/tools/protovalidate-conformance/internal/cases/cases_message.go
index 1d7faad7..e30c9c45 100644
--- a/tools/protovalidate-conformance/internal/cases/cases_message.go
+++ b/tools/protovalidate-conformance/internal/cases/cases_message.go
@@ -190,5 +190,9 @@ func messageSuite() suites.Suite {
 			Message:  &cases.MessageOneofUnknownFieldName{},
 			Expected: results.CompilationError("field xxx not found in message buf.validate.conformance.cases.MessageOneofUnknownFieldName"),
 		},
+		"oneof/no-fields/invalid": {
+			Message:  &cases.MessageOneofNoFields{},
+			Expected: results.CompilationError("at least one field must be specified in the oneof in message buf.validate.conformance.cases.MessageOneofNoFields"),
+		},
 	}
 }

From 34eac5b55e92c8eaac4b3283f192fff52caa416a Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 12:18:36 -0400
Subject: [PATCH 6/9] Format

---
 proto/protovalidate/buf/validate/validate.proto | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index 0b306763..d2902339 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -159,7 +159,7 @@ message MessageRules {
 }
 
 message MessageOneofRule {
-  // A list of field names to include in the oneof. All field names must be 
+  // A list of field names to include in the oneof. All field names must be
   // defined in the message.
   repeated string fields = 1;
   // If true, one of the fields specified _must_ be set.

From 57ee667226206500596b9e4a0d09898e91493709 Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 12:35:15 -0400
Subject: [PATCH 7/9] Feedback

---
 proto/protovalidate/buf/validate/validate.proto | 15 ++++++++++++++-
 tools/internal/gen/buf/validate/validate.pb.go  | 15 ++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index d2902339..461a04aa 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -139,9 +139,22 @@ message MessageRules {
   repeated Rule cel = 3;
 
   // `oneof` is a repeated field of type MessageOneofRule that specifies a list of fields
-  // of which exactly one can be present. If `required` is also specified, then exactly one
+  // of which at most one can be present. If `required` is also specified, then exactly one
   // of the specified fields _must_ be present.
   //
+  // This will enforce oneof-like constraints with a few features not provided by
+  // actual oneof declarations:
+  //   1. Repeated and map fields are allowed in this validation. In a oneof
+  //      declaration in the language, only scalar fields are allowed.
+  //   2. Fields with implicit presence are allowed. In a oneof definition, all member
+  //      fields have explicit presence. This means that, for the purpose of determining
+  //      how many fields are set, explicitly setting such a field to its zero value is
+  //      effectively the same as not setting it at all.
+  //   3. This will generate validation errors when unmarshalling, even from the binary
+  //      format. With oneof definitions, if multiple fields are present in the serialized
+  //      form, earlier values are usually silently ignored when unmarshalling, with only
+  //      the last field being present when unmarshalling completes.
+  //
   //
   // ```proto
   // message MyMessage {
diff --git a/tools/internal/gen/buf/validate/validate.pb.go b/tools/internal/gen/buf/validate/validate.pb.go
index c4cd3c85..a5b22052 100644
--- a/tools/internal/gen/buf/validate/validate.pb.go
+++ b/tools/internal/gen/buf/validate/validate.pb.go
@@ -425,9 +425,22 @@ type MessageRules struct {
 	// ```
 	Cel []*Rule `protobuf:"bytes,3,rep,name=cel" json:"cel,omitempty"`
 	// `oneof` is a repeated field of type MessageOneofRule that specifies a list of fields
-	// of which exactly one can be present. If `required` is also specified, then exactly one
+	// of which at most one can be present. If `required` is also specified, then exactly one
 	// of the specified fields _must_ be present.
 	//
+	// This will enforce oneof-like constraints with a few features not provided by
+	// actual oneof declarations:
+	//  1. Repeated and map fields are allowed in this validation. In a oneof
+	//     declaration in the language, only scalar fields are allowed.
+	//  2. Fields with implicit presence are allowed. In a oneof definition, all member
+	//     fields have explicit presence. This means that, for the purpose of determining
+	//     how many fields are set, explicitly setting such a field to its zero value is
+	//     effectively the same as not setting it at all.
+	//  3. This will generate validation errors when unmarshalling, even from the binary
+	//     format. With oneof definitions, if multiple fields are present in the serialized
+	//     form, earlier values are usually silently ignored when unmarshalling, with only
+	//     the last field being present when unmarshalling completes.
+	//
 	// ```proto
 	//
 	//	message MyMessage {

From fd2217b1abc85bbf5beb55bc5ec0596bc0e4981f Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 13:11:29 -0400
Subject: [PATCH 8/9] Remove no fields test case (for now)

---
 .../validate/conformance/cases/messages.proto |  7 --
 .../validate/conformance/cases/messages.pb.go | 65 +++----------------
 .../internal/cases/cases_message.go           |  4 --
 3 files changed, 9 insertions(+), 67 deletions(-)

diff --git a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
index d04a495b..d04671ad 100644
--- a/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
+++ b/proto/protovalidate-testing/buf/validate/conformance/cases/messages.proto
@@ -96,10 +96,3 @@ message MessageOneofUnknownFieldName {
   };
   string str_field = 1;
 }
-
-message MessageOneofNoFields {
-  option (buf.validate.message).oneof = {
-    fields: []
-  };
-  string str_field = 1;
-}
diff --git a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
index 8be04cff..8eff7fd0 100644
--- a/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
+++ b/tools/internal/gen/buf/validate/conformance/cases/messages.pb.go
@@ -699,50 +699,6 @@ func (x *MessageOneofUnknownFieldName) GetStrField() string {
 	return ""
 }
 
-type MessageOneofNoFields struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	StrField      string                 `protobuf:"bytes,1,opt,name=str_field,json=strField,proto3" json:"str_field,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *MessageOneofNoFields) Reset() {
-	*x = MessageOneofNoFields{}
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *MessageOneofNoFields) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*MessageOneofNoFields) ProtoMessage() {}
-
-func (x *MessageOneofNoFields) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use MessageOneofNoFields.ProtoReflect.Descriptor instead.
-func (*MessageOneofNoFields) Descriptor() ([]byte, []int) {
-	return file_buf_validate_conformance_cases_messages_proto_rawDescGZIP(), []int{14}
-}
-
-func (x *MessageOneofNoFields) GetStrField() string {
-	if x != nil {
-		return x.StrField
-	}
-	return ""
-}
-
 type MessageNone_NoneMsg struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	unknownFields protoimpl.UnknownFields
@@ -751,7 +707,7 @@ type MessageNone_NoneMsg struct {
 
 func (x *MessageNone_NoneMsg) Reset() {
 	*x = MessageNone_NoneMsg{}
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[15]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -763,7 +719,7 @@ func (x *MessageNone_NoneMsg) String() string {
 func (*MessageNone_NoneMsg) ProtoMessage() {}
 
 func (x *MessageNone_NoneMsg) ProtoReflect() protoreflect.Message {
-	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[15]
+	mi := &file_buf_validate_conformance_cases_messages_proto_msgTypes[14]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -831,9 +787,7 @@ const file_buf_validate_conformance_cases_messages_proto_rawDesc = "" +
 	"\x1cMessageOneofUnknownFieldName\x12\x1b\n" +
 	"\tstr_field\x18\x01 \x01(\tR\bstrField:\n" +
 	"\xbaH\a\"\x05\n" +
-	"\x03xxx\":\n" +
-	"\x14MessageOneofNoFields\x12\x1b\n" +
-	"\tstr_field\x18\x01 \x01(\tR\bstrField:\x05\xbaH\x02\"\x00B\xa4\x02\n" +
+	"\x03xxxB\xa4\x02\n" +
 	"\"com.buf.validate.conformance.casesB\rMessagesProtoP\x01ZSgithub.com/bufbuild/protovalidate/tools/internal/gen/buf/validate/conformance/cases\xa2\x02\x04BVCC\xaa\x02\x1eBuf.Validate.Conformance.Cases\xca\x02\x1eBuf\\Validate\\Conformance\\Cases\xe2\x02*Buf\\Validate\\Conformance\\Cases\\GPBMetadata\xea\x02!Buf::Validate::Conformance::Casesb\x06proto3"
 
 var (
@@ -848,7 +802,7 @@ func file_buf_validate_conformance_cases_messages_proto_rawDescGZIP() []byte {
 	return file_buf_validate_conformance_cases_messages_proto_rawDescData
 }
 
-var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 16)
+var file_buf_validate_conformance_cases_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 15)
 var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
 	(*TestMsg)(nil),                            // 0: buf.validate.conformance.cases.TestMsg
 	(*MessageNone)(nil),                        // 1: buf.validate.conformance.cases.MessageNone
@@ -864,15 +818,14 @@ var file_buf_validate_conformance_cases_messages_proto_goTypes = []any{
 	(*MessageOneofMultipleFields)(nil),         // 11: buf.validate.conformance.cases.MessageOneofMultipleFields
 	(*MessageOneofMultipleFieldsRequired)(nil), // 12: buf.validate.conformance.cases.MessageOneofMultipleFieldsRequired
 	(*MessageOneofUnknownFieldName)(nil),       // 13: buf.validate.conformance.cases.MessageOneofUnknownFieldName
-	(*MessageOneofNoFields)(nil),               // 14: buf.validate.conformance.cases.MessageOneofNoFields
-	(*MessageNone_NoneMsg)(nil),                // 15: buf.validate.conformance.cases.MessageNone.NoneMsg
-	(*other_package.Embed)(nil),                // 16: buf.validate.conformance.cases.other_package.Embed
+	(*MessageNone_NoneMsg)(nil),                // 14: buf.validate.conformance.cases.MessageNone.NoneMsg
+	(*other_package.Embed)(nil),                // 15: buf.validate.conformance.cases.other_package.Embed
 }
 var file_buf_validate_conformance_cases_messages_proto_depIdxs = []int32{
 	0,  // 0: buf.validate.conformance.cases.TestMsg.nested:type_name -> buf.validate.conformance.cases.TestMsg
-	15, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
+	14, // 1: buf.validate.conformance.cases.MessageNone.val:type_name -> buf.validate.conformance.cases.MessageNone.NoneMsg
 	0,  // 2: buf.validate.conformance.cases.Message.val:type_name -> buf.validate.conformance.cases.TestMsg
-	16, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
+	15, // 3: buf.validate.conformance.cases.MessageCrossPackage.val:type_name -> buf.validate.conformance.cases.other_package.Embed
 	0,  // 4: buf.validate.conformance.cases.MessageSkip.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 5: buf.validate.conformance.cases.MessageRequired.val:type_name -> buf.validate.conformance.cases.TestMsg
 	0,  // 6: buf.validate.conformance.cases.MessageRequiredButOptional.val:type_name -> buf.validate.conformance.cases.TestMsg
@@ -899,7 +852,7 @@ func file_buf_validate_conformance_cases_messages_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_buf_validate_conformance_cases_messages_proto_rawDesc), len(file_buf_validate_conformance_cases_messages_proto_rawDesc)),
 			NumEnums:      0,
-			NumMessages:   16,
+			NumMessages:   15,
 			NumExtensions: 0,
 			NumServices:   0,
 		},
diff --git a/tools/protovalidate-conformance/internal/cases/cases_message.go b/tools/protovalidate-conformance/internal/cases/cases_message.go
index e30c9c45..1d7faad7 100644
--- a/tools/protovalidate-conformance/internal/cases/cases_message.go
+++ b/tools/protovalidate-conformance/internal/cases/cases_message.go
@@ -190,9 +190,5 @@ func messageSuite() suites.Suite {
 			Message:  &cases.MessageOneofUnknownFieldName{},
 			Expected: results.CompilationError("field xxx not found in message buf.validate.conformance.cases.MessageOneofUnknownFieldName"),
 		},
-		"oneof/no-fields/invalid": {
-			Message:  &cases.MessageOneofNoFields{},
-			Expected: results.CompilationError("at least one field must be specified in the oneof in message buf.validate.conformance.cases.MessageOneofNoFields"),
-		},
 	}
 }

From f5211e7c1a9eda9ac0851c598367eb566221edfd Mon Sep 17 00:00:00 2001
From: Steve Ayers <sayers@buf.build>
Date: Wed, 11 Jun 2025 13:17:03 -0400
Subject: [PATCH 9/9] Feedback re: oneof phrasing

---
 proto/protovalidate/buf/validate/validate.proto | 10 +++++-----
 tools/internal/gen/buf/validate/validate.pb.go  | 10 +++++-----
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/proto/protovalidate/buf/validate/validate.proto b/proto/protovalidate/buf/validate/validate.proto
index 461a04aa..424f63b6 100644
--- a/proto/protovalidate/buf/validate/validate.proto
+++ b/proto/protovalidate/buf/validate/validate.proto
@@ -143,15 +143,15 @@ message MessageRules {
   // of the specified fields _must_ be present.
   //
   // This will enforce oneof-like constraints with a few features not provided by
-  // actual oneof declarations:
-  //   1. Repeated and map fields are allowed in this validation. In a oneof
-  //      declaration in the language, only scalar fields are allowed.
-  //   2. Fields with implicit presence are allowed. In a oneof definition, all member
+  // actual Protobuf oneof declarations:
+  //   1. Repeated and map fields are allowed in this validation. In a Protobuf oneof,
+  //      only scalar fields are allowed.
+  //   2. Fields with implicit presence are allowed. In a Protobuf oneof, all member
   //      fields have explicit presence. This means that, for the purpose of determining
   //      how many fields are set, explicitly setting such a field to its zero value is
   //      effectively the same as not setting it at all.
   //   3. This will generate validation errors when unmarshalling, even from the binary
-  //      format. With oneof definitions, if multiple fields are present in the serialized
+  //      format. With a Protobuf oneof, if multiple fields are present in the serialized
   //      form, earlier values are usually silently ignored when unmarshalling, with only
   //      the last field being present when unmarshalling completes.
   //
diff --git a/tools/internal/gen/buf/validate/validate.pb.go b/tools/internal/gen/buf/validate/validate.pb.go
index a5b22052..654ff1c7 100644
--- a/tools/internal/gen/buf/validate/validate.pb.go
+++ b/tools/internal/gen/buf/validate/validate.pb.go
@@ -429,15 +429,15 @@ type MessageRules struct {
 	// of the specified fields _must_ be present.
 	//
 	// This will enforce oneof-like constraints with a few features not provided by
-	// actual oneof declarations:
-	//  1. Repeated and map fields are allowed in this validation. In a oneof
-	//     declaration in the language, only scalar fields are allowed.
-	//  2. Fields with implicit presence are allowed. In a oneof definition, all member
+	// actual Protobuf oneof declarations:
+	//  1. Repeated and map fields are allowed in this validation. In a Protobuf oneof,
+	//     only scalar fields are allowed.
+	//  2. Fields with implicit presence are allowed. In a Protobuf oneof, all member
 	//     fields have explicit presence. This means that, for the purpose of determining
 	//     how many fields are set, explicitly setting such a field to its zero value is
 	//     effectively the same as not setting it at all.
 	//  3. This will generate validation errors when unmarshalling, even from the binary
-	//     format. With oneof definitions, if multiple fields are present in the serialized
+	//     format. With a Protobuf oneof, if multiple fields are present in the serialized
 	//     form, earlier values are usually silently ignored when unmarshalling, with only
 	//     the last field being present when unmarshalling completes.
 	//