nullability annotation

src/objective-c/GRPCClient/GRPCCall.m

@@ -485,7 +485,7 @@ const char *kCFStreamVarName = "grpc_cfstream";
               requestsWriter:(GRXWriter *)requestWriter
                  callOptions:(GRPCCallOptions *)callOptions {
   // Purposely using pointer rather than length ([host length] == 0) for backwards compatibility.
-  NSAssert(host != nil && path != nil, @"Neither host nor path can be nil.");
+  NSAssert(host.length != 0 && path.length != 0, @"Neither host nor path can be nil.");
   NSAssert(safety <= GRPCCallSafetyCacheableRequest, @"Invalid call safety value.");
   NSAssert(requestWriter.state == GRXWriterStateNotStarted,
            @"The requests writer can't be already started.");

src/objective-c/ProtoRPC/ProtoRPC.h

@@ -70,11 +70,11 @@ NS_ASSUME_NONNULL_BEGIN
  * Users should not use this initializer directly. Call objects will be created, initialized, and
  * returned to users by methods of the generated service.
  */
-- (instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
-                               message:(GPBMessage *)message
-                       responseHandler:(id<GRPCProtoResponseHandler>)handler
-                           callOptions:(nullable GRPCCallOptions *)callOptions
-                         responseClass:(Class)responseClass NS_DESIGNATED_INITIALIZER;
+- (nullable instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
+                                        message:(GPBMessage *)message
+                                responseHandler:(id<GRPCProtoResponseHandler>)handler
+                                    callOptions:(nullable GRPCCallOptions *)callOptions
+                                  responseClass:(Class)responseClass NS_DESIGNATED_INITIALIZER;
 
 /**
  * Start the call. This function must only be called once for each instance.
@@ -101,10 +101,10 @@ NS_ASSUME_NONNULL_BEGIN
  * Users should not use this initializer directly. Call objects will be created, initialized, and
  * returned to users by methods of the generated service.
  */
-- (instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
-                       responseHandler:(id<GRPCProtoResponseHandler>)handler
-                           callOptions:(nullable GRPCCallOptions *)callOptions
-                         responseClass:(Class)responseClass NS_DESIGNATED_INITIALIZER;
+- (nullable instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
+                                responseHandler:(id<GRPCProtoResponseHandler>)handler
+                                    callOptions:(nullable GRPCCallOptions *)callOptions
+                                  responseClass:(Class)responseClass NS_DESIGNATED_INITIALIZER;
 
 /**
  * Start the call. This function must only be called once for each instance.

src/objective-c/ProtoRPC/ProtoRPC.m

@@ -57,6 +57,9 @@ static NSError *ErrorForBadProto(id proto, Class expectedClass, NSError *parsing
                          responseClass:(Class)responseClass {
   NSAssert(message != nil, @"message cannot be empty.");
   NSAssert(responseClass != nil, @"responseClass cannot be empty.");
+  if (message == nil || responseClass == nil) {
+    return nil;
+  }
   if ((self = [super init])) {
     _call = [[GRPCStreamingProtoCall alloc] initWithRequestOptions:requestOptions
                                                    responseHandler:handler

src/objective-c/ProtoRPC/ProtoService.h

@@ -27,33 +27,35 @@
 @class GRPCStreamingProtoCall;
 @protocol GRPCProtoResponseCallbacks;
 
+NS_ASSUME_NONNULL_BEGIN
+
 __attribute__((deprecated("Please use GRPCProtoService."))) @interface ProtoService
     : NSObject
 
       -
-      (instancetype)initWithHost : (NSString *)host packageName
+      (nullable instancetype)initWithHost : (NSString *)host packageName
     : (NSString *)packageName serviceName : (NSString *)serviceName callOptions
-    : (GRPCCallOptions *)callOptions NS_DESIGNATED_INITIALIZER;
+    : (nullable GRPCCallOptions *)callOptions NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)initWithHost:(NSString *)host
                  packageName:(NSString *)packageName
                  serviceName:(NSString *)serviceName;
 
-- (GRPCProtoCall *)RPCToMethod:(NSString *)method
-                requestsWriter:(GRXWriter *)requestsWriter
-                 responseClass:(Class)responseClass
-            responsesWriteable:(id<GRXWriteable>)responsesWriteable;
+- (nullable GRPCProtoCall *)RPCToMethod:(NSString *)method
+                         requestsWriter:(GRXWriter *)requestsWriter
+                          responseClass:(Class)responseClass
+                     responsesWriteable:(id<GRXWriteable>)responsesWriteable;
 
-- (GRPCUnaryProtoCall *)RPCToMethod:(NSString *)method
-                            message:(id)message
-                    responseHandler:(id<GRPCProtoResponseCallbacks>)handler
-                        callOptions:(GRPCCallOptions *)callOptions
-                      responseClass:(Class)responseClass;
+- (nullable GRPCUnaryProtoCall *)RPCToMethod:(NSString *)method
+                                     message:(id)message
+                             responseHandler:(id<GRPCProtoResponseCallbacks>)handler
+                                 callOptions:(nullable GRPCCallOptions *)callOptions
+                               responseClass:(Class)responseClass;
 
-- (GRPCStreamingProtoCall *)RPCToMethod:(NSString *)method
-                        responseHandler:(id<GRPCProtoResponseCallbacks>)handler
-                            callOptions:(GRPCCallOptions *)callOptions
-                          responseClass:(Class)responseClass;
+- (nullable GRPCStreamingProtoCall *)RPCToMethod:(NSString *)method
+                                 responseHandler:(id<GRPCProtoResponseCallbacks>)handler
+                                     callOptions:(nullable GRPCCallOptions *)callOptions
+                                   responseClass:(Class)responseClass;
 
 @end
 
@@ -67,3 +69,5 @@ __attribute__((deprecated("Please use GRPCProtoService."))) @interface ProtoServ
 #pragma clang diagnostic pop
 
                                   @end
+
+                                      NS_ASSUME_NONNULL_END

src/objective-c/ProtoRPC/ProtoService.m

@@ -44,9 +44,10 @@
                  packageName:(NSString *)packageName
                  serviceName:(NSString *)serviceName
                  callOptions:(GRPCCallOptions *)callOptions {
-  if (!host || !serviceName) {
-    [NSException raise:NSInvalidArgumentException
-                format:@"Neither host nor serviceName can be nil."];
+  NSAssert(host.length != 0 && packageName.length != 0 && serviceName.length != 0,
+           @"Invalid parameter.");
+  if (host.length == 0 || packageName.length == 0 || serviceName.length == 0) {
+    return nil;
   }
   if ((self = [super init])) {
     _host = [host copy];

src/objective-c/tests/GRPCClientTests.m

@@ -362,9 +362,10 @@ static GRPCProtoMethod *kFullDuplexCallMethod;
 
 // TODO(makarandd): Move to a different file that contains only unit tests
 - (void)testExceptions {
+  GRXWriter *writer = [GRXWriter writerWithValue:[NSData data]];
   // Try to set parameters to nil for GRPCCall. This should cause an exception
   @try {
-    (void)[[GRPCCall alloc] initWithHost:nil path:nil requestsWriter:nil];
+    (void)[[GRPCCall alloc] initWithHost:@"" path:@"" requestsWriter:writer];
     XCTFail(@"Did not receive an exception when parameters are nil");
   } @catch (NSException *theException) {
     NSLog(@"Received exception as expected: %@", theException.name);