Add nonnil markup to ObjC library.

Add the clang annotations to the objc library and generated code to help with Swift bridging and compiler checks.

11 files changed, 136 insertions, 103 deletions

diff --git a/objectivec/google/protobuf/Any.pbobjc.h b/objectivec/google/protobuf/Any.pbobjc.h
index 8154318e..e09f3a49 100644
--- a/objectivec/google/protobuf/Any.pbobjc.h
+++ b/objectivec/google/protobuf/Any.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBAnyRoot
 
@@ -88,13 +89,15 @@ typedef GPB_ENUM(GPBAny_FieldNumber) {
 // namespace should use `type.googleapis.com/full.type.name` (without
 // schema and path). A type service will eventually become available which
 // serves those URLs (projected Q2/15).
-@property(nonatomic, readwrite, copy) NSString *typeURL;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *typeURL;
 
 // Must be valid serialized data of the above specified type.
-@property(nonatomic, readwrite, copy) NSData *value;
+@property(nonatomic, readwrite, copy, null_resettable) NSData *value;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Api.pbobjc.h b/objectivec/google/protobuf/Api.pbobjc.h
index 061347be..021dac5f 100644
--- a/objectivec/google/protobuf/Api.pbobjc.h
+++ b/objectivec/google/protobuf/Api.pbobjc.h
@@ -13,6 +13,7 @@ CF_EXTERN_C_BEGIN
 
 @class GPBSourceContext;
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBApiRoot
 
@@ -40,16 +41,16 @@ typedef GPB_ENUM(GPBApi_FieldNumber) {
 
 // The fully qualified name of this api, including package name
 // followed by the api's simple name.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // The methods of this api, in unspecified order.
 // |methodsArray| contains |GPBMethod|
-@property(nonatomic, readwrite, strong) NSMutableArray *methodsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *methodsArray;
 @property(nonatomic, readonly) NSUInteger methodsArray_Count;
 
 // Any metadata attached to the API.
 // |optionsArray| contains |GPBOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *optionsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *optionsArray;
 @property(nonatomic, readonly) NSUInteger optionsArray_Count;
 
 // A version string for this api. If specified, must have the form
@@ -74,12 +75,12 @@ typedef GPB_ENUM(GPBApi_FieldNumber) {
 // experimental, none-GA apis.
 //
 // See also: [design doc](http://go/api-versioning).
-@property(nonatomic, readwrite, copy) NSString *version;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *version;
 
 // Source context for the protocol buffer service represented by this
 // message.
 @property(nonatomic, readwrite) BOOL hasSourceContext;
-@property(nonatomic, readwrite, strong) GPBSourceContext *sourceContext;
+@property(nonatomic, readwrite, strong, null_resettable) GPBSourceContext *sourceContext;
 
 @end
 
@@ -98,27 +99,29 @@ typedef GPB_ENUM(GPBMethod_FieldNumber) {
 @interface GPBMethod : GPBMessage
 
 // The simple name of this method.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // A URL of the input message type.
-@property(nonatomic, readwrite, copy) NSString *requestTypeURL;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *requestTypeURL;
 
 // If true, the request is streamed.
 @property(nonatomic, readwrite) BOOL requestStreaming;
 
 // The URL of the output message type.
-@property(nonatomic, readwrite, copy) NSString *responseTypeURL;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *responseTypeURL;
 
 // If true, the response is streamed.
 @property(nonatomic, readwrite) BOOL responseStreaming;
 
 // Any metadata attached to the method.
 // |optionsArray| contains |GPBOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *optionsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *optionsArray;
 @property(nonatomic, readonly) NSUInteger optionsArray_Count;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Descriptor.pbobjc.h b/objectivec/google/protobuf/Descriptor.pbobjc.h
index e0106534..bf0f51a6 100644
--- a/objectivec/google/protobuf/Descriptor.pbobjc.h
+++ b/objectivec/google/protobuf/Descriptor.pbobjc.h
@@ -20,6 +20,8 @@ CF_EXTERN_C_BEGIN
 @class GPBServiceOptions;
 @class GPBSourceCodeInfo;
 
+NS_ASSUME_NONNULL_BEGIN
+
 #pragma mark - Enum GPBFieldDescriptorProto_Type
 
 typedef GPB_ENUM(GPBFieldDescriptorProto_Type) {
@@ -128,7 +130,6 @@ GPBEnumDescriptor *GPBFieldOptions_JSType_EnumDescriptor(void);
 
 BOOL GPBFieldOptions_JSType_IsValidValue(int32_t value);
 
-
 #pragma mark - GPBDescriptorRoot
 
 @interface GPBDescriptorRoot : GPBRootObject
@@ -151,7 +152,7 @@ typedef GPB_ENUM(GPBFileDescriptorSet_FieldNumber) {
 @interface GPBFileDescriptorSet : GPBMessage
 
 // |fileArray| contains |GPBFileDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *fileArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *fileArray;
 @property(nonatomic, readonly) NSUInteger fileArray_Count;
 
 @end
@@ -178,57 +179,57 @@ typedef GPB_ENUM(GPBFileDescriptorProto_FieldNumber) {
 
 // file name, relative to root of source tree
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // e.g. "foo", "foo.bar", etc.
 @property(nonatomic, readwrite) BOOL hasPackage;
-@property(nonatomic, readwrite, copy) NSString *package;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *package;
 
 // Names of files imported by this file.
 // |dependencyArray| contains |NSString|
-@property(nonatomic, readwrite, strong) NSMutableArray *dependencyArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *dependencyArray;
 @property(nonatomic, readonly) NSUInteger dependencyArray_Count;
 
 // Indexes of the public imported files in the dependency list above.
-@property(nonatomic, readwrite, strong) GPBInt32Array *publicDependencyArray;
+@property(nonatomic, readwrite, strong, null_resettable) GPBInt32Array *publicDependencyArray;
 @property(nonatomic, readonly) NSUInteger publicDependencyArray_Count;
 
 // Indexes of the weak imported files in the dependency list.
 // For Google-internal migration only. Do not use.
-@property(nonatomic, readwrite, strong) GPBInt32Array *weakDependencyArray;
+@property(nonatomic, readwrite, strong, null_resettable) GPBInt32Array *weakDependencyArray;
 @property(nonatomic, readonly) NSUInteger weakDependencyArray_Count;
 
 // All top-level definitions in this file.
 // |messageTypeArray| contains |GPBDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *messageTypeArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *messageTypeArray;
 @property(nonatomic, readonly) NSUInteger messageTypeArray_Count;
 
 // |enumTypeArray| contains |GPBEnumDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *enumTypeArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *enumTypeArray;
 @property(nonatomic, readonly) NSUInteger enumTypeArray_Count;
 
 // |serviceArray| contains |GPBServiceDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *serviceArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *serviceArray;
 @property(nonatomic, readonly) NSUInteger serviceArray_Count;
 
 // |extensionArray| contains |GPBFieldDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *extensionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *extensionArray;
 @property(nonatomic, readonly) NSUInteger extensionArray_Count;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBFileOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBFileOptions *options;
 
 // This field contains optional information about the original source code.
 // You may safely remove this entire field without harming runtime
 // functionality of the descriptors -- the information is needed only by
 // development tools.
 @property(nonatomic, readwrite) BOOL hasSourceCodeInfo;
-@property(nonatomic, readwrite, strong) GPBSourceCodeInfo *sourceCodeInfo;
+@property(nonatomic, readwrite, strong, null_resettable) GPBSourceCodeInfo *sourceCodeInfo;
 
 // The syntax of the proto file.
 // The supported values are "proto2" and "proto3".
 @property(nonatomic, readwrite) BOOL hasSyntax;
-@property(nonatomic, readwrite, copy) NSString *syntax;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *syntax;
 
 @end
 
@@ -251,43 +252,43 @@ typedef GPB_ENUM(GPBDescriptorProto_FieldNumber) {
 @interface GPBDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // |fieldArray| contains |GPBFieldDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *fieldArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *fieldArray;
 @property(nonatomic, readonly) NSUInteger fieldArray_Count;
 
 // |extensionArray| contains |GPBFieldDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *extensionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *extensionArray;
 @property(nonatomic, readonly) NSUInteger extensionArray_Count;
 
 // |nestedTypeArray| contains |GPBDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *nestedTypeArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *nestedTypeArray;
 @property(nonatomic, readonly) NSUInteger nestedTypeArray_Count;
 
 // |enumTypeArray| contains |GPBEnumDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *enumTypeArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *enumTypeArray;
 @property(nonatomic, readonly) NSUInteger enumTypeArray_Count;
 
 // |extensionRangeArray| contains |GPBDescriptorProto_ExtensionRange|
-@property(nonatomic, readwrite, strong) NSMutableArray *extensionRangeArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *extensionRangeArray;
 @property(nonatomic, readonly) NSUInteger extensionRangeArray_Count;
 
 // |oneofDeclArray| contains |GPBOneofDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *oneofDeclArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *oneofDeclArray;
 @property(nonatomic, readonly) NSUInteger oneofDeclArray_Count;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBMessageOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBMessageOptions *options;
 
 // |reservedRangeArray| contains |GPBDescriptorProto_ReservedRange|
-@property(nonatomic, readwrite, strong) NSMutableArray *reservedRangeArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *reservedRangeArray;
 @property(nonatomic, readonly) NSUInteger reservedRangeArray_Count;
 
 // Reserved field names, which may not be used by fields in the same message.
 // A given name may only be reserved once.
 // |reservedNameArray| contains |NSString|
-@property(nonatomic, readwrite, strong) NSMutableArray *reservedNameArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *reservedNameArray;
 @property(nonatomic, readonly) NSUInteger reservedNameArray_Count;
 
 @end
@@ -349,7 +350,7 @@ typedef GPB_ENUM(GPBFieldDescriptorProto_FieldNumber) {
 @interface GPBFieldDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 @property(nonatomic, readwrite) BOOL hasNumber;
 @property(nonatomic, readwrite) int32_t number;
@@ -368,12 +369,12 @@ typedef GPB_ENUM(GPBFieldDescriptorProto_FieldNumber) {
 // message are searched, then within the parent, on up to the root
 // namespace).
 @property(nonatomic, readwrite) BOOL hasTypeName;
-@property(nonatomic, readwrite, copy) NSString *typeName;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *typeName;
 
 // For extensions, this is the name of the type being extended.  It is
 // resolved in the same manner as type_name.
 @property(nonatomic, readwrite) BOOL hasExtendee;
-@property(nonatomic, readwrite, copy) NSString *extendee;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *extendee;
 
 // For numeric types, contains the original text representation of the value.
 // For booleans, "true" or "false".
@@ -381,7 +382,7 @@ typedef GPB_ENUM(GPBFieldDescriptorProto_FieldNumber) {
 // For bytes, contains the C escaped value.  All bytes >= 128 are escaped.
 // TODO(kenton):  Base-64 encode?
 @property(nonatomic, readwrite) BOOL hasDefaultValue;
-@property(nonatomic, readwrite, copy) NSString *defaultValue;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *defaultValue;
 
 // If set, gives the index of a oneof in the containing type's oneof_decl
 // list.  This field is a member of that oneof.
@@ -389,7 +390,7 @@ typedef GPB_ENUM(GPBFieldDescriptorProto_FieldNumber) {
 @property(nonatomic, readwrite) int32_t oneofIndex;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBFieldOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBFieldOptions *options;
 
 @end
 
@@ -403,7 +404,7 @@ typedef GPB_ENUM(GPBOneofDescriptorProto_FieldNumber) {
 @interface GPBOneofDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 @end
 
@@ -419,14 +420,14 @@ typedef GPB_ENUM(GPBEnumDescriptorProto_FieldNumber) {
 @interface GPBEnumDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // |valueArray| contains |GPBEnumValueDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *valueArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *valueArray;
 @property(nonatomic, readonly) NSUInteger valueArray_Count;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBEnumOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBEnumOptions *options;
 
 @end
 
@@ -442,13 +443,13 @@ typedef GPB_ENUM(GPBEnumValueDescriptorProto_FieldNumber) {
 @interface GPBEnumValueDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 @property(nonatomic, readwrite) BOOL hasNumber;
 @property(nonatomic, readwrite) int32_t number;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBEnumValueOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBEnumValueOptions *options;
 
 @end
 
@@ -464,14 +465,14 @@ typedef GPB_ENUM(GPBServiceDescriptorProto_FieldNumber) {
 @interface GPBServiceDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // |methodArray| contains |GPBMethodDescriptorProto|
-@property(nonatomic, readwrite, strong) NSMutableArray *methodArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *methodArray;
 @property(nonatomic, readonly) NSUInteger methodArray_Count;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBServiceOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBServiceOptions *options;
 
 @end
 
@@ -490,18 +491,18 @@ typedef GPB_ENUM(GPBMethodDescriptorProto_FieldNumber) {
 @interface GPBMethodDescriptorProto : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasName;
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // Input and output type names.  These are resolved in the same way as
 // FieldDescriptorProto.type_name, but must refer to a message type.
 @property(nonatomic, readwrite) BOOL hasInputType;
-@property(nonatomic, readwrite, copy) NSString *inputType;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *inputType;
 
 @property(nonatomic, readwrite) BOOL hasOutputType;
-@property(nonatomic, readwrite, copy) NSString *outputType;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *outputType;
 
 @property(nonatomic, readwrite) BOOL hasOptions;
-@property(nonatomic, readwrite, strong) GPBMethodOptions *options;
+@property(nonatomic, readwrite, strong, null_resettable) GPBMethodOptions *options;
 
 // Identifies if client streams multiple client messages
 @property(nonatomic, readwrite) BOOL hasClientStreaming;
@@ -540,7 +541,7 @@ typedef GPB_ENUM(GPBFileOptions_FieldNumber) {
 // inappropriate because proto packages do not normally start with backwards
 // domain names.
 @property(nonatomic, readwrite) BOOL hasJavaPackage;
-@property(nonatomic, readwrite, copy) NSString *javaPackage;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *javaPackage;
 
 // If set, all the classes from the .proto file are wrapped in a single
 // outer class with the given name.  This applies to both Proto1
@@ -548,7 +549,7 @@ typedef GPB_ENUM(GPBFileOptions_FieldNumber) {
 // a .proto always translates to a single class, but you may want to
 // explicitly choose the class name).
 @property(nonatomic, readwrite) BOOL hasJavaOuterClassname;
-@property(nonatomic, readwrite, copy) NSString *javaOuterClassname;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *javaOuterClassname;
 
 // If set true, then the Java code generator will generate a separate .java
 // file for each top-level message, enum, and service defined in the .proto
@@ -590,7 +591,7 @@ typedef GPB_ENUM(GPBFileOptions_FieldNumber) {
 //   - Otherwise, the package statement in the .proto file, if present.
 //   - Otherwise, the basename of the .proto file, without extension.
 @property(nonatomic, readwrite) BOOL hasGoPackage;
-@property(nonatomic, readwrite, copy) NSString *goPackage;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *goPackage;
 
 // Should generic services be generated in each language?  "Generic" services
 // are not specific to any particular RPC system.  They are generated by the
@@ -626,15 +627,15 @@ typedef GPB_ENUM(GPBFileOptions_FieldNumber) {
 // Sets the objective c class prefix which is prepended to all objective c
 // generated classes from this .proto. There is no default.
 @property(nonatomic, readwrite) BOOL hasObjcClassPrefix;
-@property(nonatomic, readwrite, copy) NSString *objcClassPrefix;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *objcClassPrefix;
 
 // Namespace for generated classes; defaults to the package.
 @property(nonatomic, readwrite) BOOL hasCsharpNamespace;
-@property(nonatomic, readwrite, copy) NSString *csharpNamespace;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *csharpNamespace;
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -711,7 +712,7 @@ typedef GPB_ENUM(GPBMessageOptions_FieldNumber) {
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -801,7 +802,7 @@ typedef GPB_ENUM(GPBFieldOptions_FieldNumber) {
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -830,7 +831,7 @@ typedef GPB_ENUM(GPBEnumOptions_FieldNumber) {
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -853,7 +854,7 @@ typedef GPB_ENUM(GPBEnumValueOptions_FieldNumber) {
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -876,7 +877,7 @@ typedef GPB_ENUM(GPBServiceOptions_FieldNumber) {
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -899,7 +900,7 @@ typedef GPB_ENUM(GPBMethodOptions_FieldNumber) {
 
 // The parser stores options it doesn't recognize here. See above.
 // |uninterpretedOptionArray| contains |GPBUninterpretedOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *uninterpretedOptionArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *uninterpretedOptionArray;
 @property(nonatomic, readonly) NSUInteger uninterpretedOptionArray_Count;
 
 @end
@@ -925,13 +926,13 @@ typedef GPB_ENUM(GPBUninterpretedOption_FieldNumber) {
 @interface GPBUninterpretedOption : GPBMessage
 
 // |nameArray| contains |GPBUninterpretedOption_NamePart|
-@property(nonatomic, readwrite, strong) NSMutableArray *nameArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *nameArray;
 @property(nonatomic, readonly) NSUInteger nameArray_Count;
 
 // The value of the uninterpreted option, in whatever type the tokenizer
 // identified it as during parsing. Exactly one of these should be set.
 @property(nonatomic, readwrite) BOOL hasIdentifierValue;
-@property(nonatomic, readwrite, copy) NSString *identifierValue;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *identifierValue;
 
 @property(nonatomic, readwrite) BOOL hasPositiveIntValue;
 @property(nonatomic, readwrite) uint64_t positiveIntValue;
@@ -943,10 +944,10 @@ typedef GPB_ENUM(GPBUninterpretedOption_FieldNumber) {
 @property(nonatomic, readwrite) double doubleValue;
 
 @property(nonatomic, readwrite) BOOL hasStringValue;
-@property(nonatomic, readwrite, copy) NSData *stringValue;
+@property(nonatomic, readwrite, copy, null_resettable) NSData *stringValue;
 
 @property(nonatomic, readwrite) BOOL hasAggregateValue;
-@property(nonatomic, readwrite, copy) NSString *aggregateValue;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *aggregateValue;
 
 @end
 
@@ -965,7 +966,7 @@ typedef GPB_ENUM(GPBUninterpretedOption_NamePart_FieldNumber) {
 @interface GPBUninterpretedOption_NamePart : GPBMessage
 
 @property(nonatomic, readwrite) BOOL hasNamePart;
-@property(nonatomic, readwrite, copy) NSString *namePart;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *namePart;
 
 @property(nonatomic, readwrite) BOOL hasIsExtension;
 @property(nonatomic, readwrite) BOOL isExtension;
@@ -1026,7 +1027,7 @@ typedef GPB_ENUM(GPBSourceCodeInfo_FieldNumber) {
 //   ignore those that it doesn't understand, as more types of locations could
 //   be recorded in the future.
 // |locationArray| contains |GPBSourceCodeInfo_Location|
-@property(nonatomic, readwrite, strong) NSMutableArray *locationArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *locationArray;
 @property(nonatomic, readonly) NSUInteger locationArray_Count;
 
 @end
@@ -1066,7 +1067,7 @@ typedef GPB_ENUM(GPBSourceCodeInfo_Location_FieldNumber) {
 //   [ 4, 3, 2, 7 ]
 // this path refers to the whole field declaration (from the beginning
 // of the label to the terminating semicolon).
-@property(nonatomic, readwrite, strong) GPBInt32Array *pathArray;
+@property(nonatomic, readwrite, strong, null_resettable) GPBInt32Array *pathArray;
 @property(nonatomic, readonly) NSUInteger pathArray_Count;
 
 // Always has exactly three or four elements: start line, start column,
@@ -1074,7 +1075,7 @@ typedef GPB_ENUM(GPBSourceCodeInfo_Location_FieldNumber) {
 // These are packed into a single field for efficiency.  Note that line
 // and column numbers are zero-based -- typically you will want to add
 // 1 to each before displaying to a user.
-@property(nonatomic, readwrite, strong) GPBInt32Array *spanArray;
+@property(nonatomic, readwrite, strong, null_resettable) GPBInt32Array *spanArray;
 @property(nonatomic, readonly) NSUInteger spanArray_Count;
 
 // If this SourceCodeInfo represents a complete declaration, these are any
@@ -1125,17 +1126,19 @@ typedef GPB_ENUM(GPBSourceCodeInfo_Location_FieldNumber) {
 //
 //   // ignored detached comments.
 @property(nonatomic, readwrite) BOOL hasLeadingComments;
-@property(nonatomic, readwrite, copy) NSString *leadingComments;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *leadingComments;
 
 @property(nonatomic, readwrite) BOOL hasTrailingComments;
-@property(nonatomic, readwrite, copy) NSString *trailingComments;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *trailingComments;
 
 // |leadingDetachedCommentsArray| contains |NSString|
-@property(nonatomic, readwrite, strong) NSMutableArray *leadingDetachedCommentsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *leadingDetachedCommentsArray;
 @property(nonatomic, readonly) NSUInteger leadingDetachedCommentsArray_Count;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Duration.pbobjc.h b/objectivec/google/protobuf/Duration.pbobjc.h
index f65df6c9..9ecba197 100644
--- a/objectivec/google/protobuf/Duration.pbobjc.h
+++ b/objectivec/google/protobuf/Duration.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBDurationRoot
 
@@ -86,6 +87,8 @@ typedef GPB_ENUM(GPBDuration_FieldNumber) {
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Empty.pbobjc.h b/objectivec/google/protobuf/Empty.pbobjc.h
index 1356c3a7..17e2b19b 100644
--- a/objectivec/google/protobuf/Empty.pbobjc.h
+++ b/objectivec/google/protobuf/Empty.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBEmptyRoot
 
@@ -36,6 +37,8 @@ CF_EXTERN_C_BEGIN
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/FieldMask.pbobjc.h b/objectivec/google/protobuf/FieldMask.pbobjc.h
index f9b26fa2..de62c03b 100644
--- a/objectivec/google/protobuf/FieldMask.pbobjc.h
+++ b/objectivec/google/protobuf/FieldMask.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBFieldMaskRoot
 
@@ -151,11 +152,13 @@ typedef GPB_ENUM(GPBFieldMask_FieldNumber) {
 
 // The set of field mask paths.
 // |pathsArray| contains |NSString|
-@property(nonatomic, readwrite, strong) NSMutableArray *pathsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *pathsArray;
 @property(nonatomic, readonly) NSUInteger pathsArray_Count;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/SourceContext.pbobjc.h b/objectivec/google/protobuf/SourceContext.pbobjc.h
index bcbf1e3d..6bc57149 100644
--- a/objectivec/google/protobuf/SourceContext.pbobjc.h
+++ b/objectivec/google/protobuf/SourceContext.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBSourceContextRoot
 
@@ -35,10 +36,12 @@ typedef GPB_ENUM(GPBSourceContext_FieldNumber) {
 
 // The path-qualified name of the .proto file that contained the associated
 // protobuf element.  For example: `"google/protobuf/source.proto"`.
-@property(nonatomic, readwrite, copy) NSString *fileName;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *fileName;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Struct.pbobjc.h b/objectivec/google/protobuf/Struct.pbobjc.h
index 45456955..d72f9738 100644
--- a/objectivec/google/protobuf/Struct.pbobjc.h
+++ b/objectivec/google/protobuf/Struct.pbobjc.h
@@ -14,6 +14,8 @@ CF_EXTERN_C_BEGIN
 @class GPBListValue;
 @class GPBStruct;
 
+NS_ASSUME_NONNULL_BEGIN
+
 #pragma mark - Enum GPBNullValue
 
 // `NullValue` is a singleton enumeration to represent the null
@@ -28,7 +30,6 @@ GPBEnumDescriptor *GPBNullValue_EnumDescriptor(void);
 
 BOOL GPBNullValue_IsValidValue(int32_t value);
 
-
 #pragma mark - GPBStructRoot
 
 @interface GPBStructRoot : GPBRootObject
@@ -56,7 +57,7 @@ typedef GPB_ENUM(GPBStruct_FieldNumber) {
 
 // Map of dynamically typed values.
 // |fields| values are |GPBValue|
-@property(nonatomic, readwrite, strong) NSMutableDictionary *fields;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableDictionary *fields;
 @property(nonatomic, readonly) NSUInteger fields_Count;
 
 @end
@@ -97,16 +98,16 @@ typedef GPB_ENUM(GPBValue_Kind_OneOfCase) {
 @property(nonatomic, readwrite) double numberValue;
 
 // Represents a string value.
-@property(nonatomic, readwrite, copy) NSString *stringValue;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *stringValue;
 
 // Represents a boolean value.
 @property(nonatomic, readwrite) BOOL boolValue;
 
 // Represents a structured value.
-@property(nonatomic, readwrite, strong) GPBStruct *structValue;
+@property(nonatomic, readwrite, strong, null_resettable) GPBStruct *structValue;
 
 // Represents a repeated `Value`.
-@property(nonatomic, readwrite, strong) GPBListValue *listValue;
+@property(nonatomic, readwrite, strong, null_resettable) GPBListValue *listValue;
 
 @end
 
@@ -126,11 +127,13 @@ typedef GPB_ENUM(GPBListValue_FieldNumber) {
 
 // Repeated field of dynamically typed values.
 // |valuesArray| contains |GPBValue|
-@property(nonatomic, readwrite, strong) NSMutableArray *valuesArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *valuesArray;
 @property(nonatomic, readonly) NSUInteger valuesArray_Count;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Timestamp.pbobjc.h b/objectivec/google/protobuf/Timestamp.pbobjc.h
index a81321b4..0b342156 100644
--- a/objectivec/google/protobuf/Timestamp.pbobjc.h
+++ b/objectivec/google/protobuf/Timestamp.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBTimestampRoot
 
@@ -97,6 +98,8 @@ typedef GPB_ENUM(GPBTimestamp_FieldNumber) {
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Type.pbobjc.h b/objectivec/google/protobuf/Type.pbobjc.h
index e3b6229f..eb807ae5 100644
--- a/objectivec/google/protobuf/Type.pbobjc.h
+++ b/objectivec/google/protobuf/Type.pbobjc.h
@@ -14,6 +14,8 @@ CF_EXTERN_C_BEGIN
 @class GPBAny;
 @class GPBSourceContext;
 
+NS_ASSUME_NONNULL_BEGIN
+
 #pragma mark - Enum GPBField_Kind
 
 // Kind represents a basic field type.
@@ -101,7 +103,6 @@ GPBEnumDescriptor *GPBField_Cardinality_EnumDescriptor(void);
 
 BOOL GPBField_Cardinality_IsValidValue(int32_t value);
 
-
 #pragma mark - GPBTypeRoot
 
 @interface GPBTypeRoot : GPBRootObject
@@ -127,27 +128,27 @@ typedef GPB_ENUM(GPBType_FieldNumber) {
 @interface GPBType : GPBMessage
 
 // The fully qualified message name.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // The list of fields.
 // |fieldsArray| contains |GPBField|
-@property(nonatomic, readwrite, strong) NSMutableArray *fieldsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *fieldsArray;
 @property(nonatomic, readonly) NSUInteger fieldsArray_Count;
 
 // The list of oneof definitions.
 // The list of oneofs declared in this Type
 // |oneofsArray| contains |NSString|
-@property(nonatomic, readwrite, strong) NSMutableArray *oneofsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *oneofsArray;
 @property(nonatomic, readonly) NSUInteger oneofsArray_Count;
 
 // The proto options.
 // |optionsArray| contains |GPBOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *optionsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *optionsArray;
 @property(nonatomic, readonly) NSUInteger optionsArray_Count;
 
 // The source context.
 @property(nonatomic, readwrite) BOOL hasSourceContext;
-@property(nonatomic, readwrite, strong) GPBSourceContext *sourceContext;
+@property(nonatomic, readwrite, strong, null_resettable) GPBSourceContext *sourceContext;
 
 @end
 
@@ -177,11 +178,11 @@ typedef GPB_ENUM(GPBField_FieldNumber) {
 @property(nonatomic, readwrite) int32_t number;
 
 // The field name.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // The type URL (without the scheme) when the type is MESSAGE or ENUM,
 // such as `type.googleapis.com/google.protobuf.Empty`.
-@property(nonatomic, readwrite, copy) NSString *typeURL;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *typeURL;
 
 // Index in Type.oneofs. Starts at 1. Zero means no oneof mapping.
 @property(nonatomic, readwrite) int32_t oneofIndex;
@@ -191,7 +192,7 @@ typedef GPB_ENUM(GPBField_FieldNumber) {
 
 // The proto options.
 // |optionsArray| contains |GPBOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *optionsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *optionsArray;
 @property(nonatomic, readonly) NSUInteger optionsArray_Count;
 
 @end
@@ -215,21 +216,21 @@ typedef GPB_ENUM(GPBEnum_FieldNumber) {
 @interface GPBEnum : GPBMessage
 
 // Enum type name.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // Enum value definitions.
 // |enumvalueArray| contains |GPBEnumValue|
-@property(nonatomic, readwrite, strong) NSMutableArray *enumvalueArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *enumvalueArray;
 @property(nonatomic, readonly) NSUInteger enumvalueArray_Count;
 
 // Proto options for the enum type.
 // |optionsArray| contains |GPBOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *optionsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *optionsArray;
 @property(nonatomic, readonly) NSUInteger optionsArray_Count;
 
 // The source context.
 @property(nonatomic, readwrite) BOOL hasSourceContext;
-@property(nonatomic, readwrite, strong) GPBSourceContext *sourceContext;
+@property(nonatomic, readwrite, strong, null_resettable) GPBSourceContext *sourceContext;
 
 @end
 
@@ -245,14 +246,14 @@ typedef GPB_ENUM(GPBEnumValue_FieldNumber) {
 @interface GPBEnumValue : GPBMessage
 
 // Enum value name.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // Enum value number.
 @property(nonatomic, readwrite) int32_t number;
 
 // Proto options for the enum value.
 // |optionsArray| contains |GPBOption|
-@property(nonatomic, readwrite, strong) NSMutableArray *optionsArray;
+@property(nonatomic, readwrite, strong, null_resettable) NSMutableArray *optionsArray;
 @property(nonatomic, readonly) NSUInteger optionsArray_Count;
 
 @end
@@ -268,14 +269,16 @@ typedef GPB_ENUM(GPBOption_FieldNumber) {
 @interface GPBOption : GPBMessage
 
 // Proto option name.
-@property(nonatomic, readwrite, copy) NSString *name;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *name;
 
 // Proto option value.
 @property(nonatomic, readwrite) BOOL hasValue;
-@property(nonatomic, readwrite, strong) GPBAny *value;
+@property(nonatomic, readwrite, strong, null_resettable) GPBAny *value;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Wrappers.pbobjc.h b/objectivec/google/protobuf/Wrappers.pbobjc.h
index 227d958e..b4718d02 100644
--- a/objectivec/google/protobuf/Wrappers.pbobjc.h
+++ b/objectivec/google/protobuf/Wrappers.pbobjc.h
@@ -11,6 +11,7 @@
 
 CF_EXTERN_C_BEGIN
 
+NS_ASSUME_NONNULL_BEGIN
 
 #pragma mark - GPBWrappersRoot
 
@@ -131,7 +132,7 @@ typedef GPB_ENUM(GPBStringValue_FieldNumber) {
 @interface GPBStringValue : GPBMessage
 
 // The string value.
-@property(nonatomic, readwrite, copy) NSString *value;
+@property(nonatomic, readwrite, copy, null_resettable) NSString *value;
 
 @end
 
@@ -145,10 +146,12 @@ typedef GPB_ENUM(GPBBytesValue_FieldNumber) {
 @interface GPBBytesValue : GPBMessage
 
 // The bytes value.
-@property(nonatomic, readwrite, copy) NSData *value;
+@property(nonatomic, readwrite, copy, null_resettable) NSData *value;
 
 @end
 
+NS_ASSUME_NONNULL_END
+
 CF_EXTERN_C_END
 
 // @@protoc_insertion_point(global_scope)