Support the -Wassign-enum compiler flag. (#2085)

Support the -Wassign-enum compiler flag.

objectivec/GPBArray.m

@@ -195,7 +195,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 //%}
 //%
 //%- (void)enumerate##ACCESSOR_NAME##ValuesWithBlock:(void (^)(TYPE value, NSUInteger idx, BOOL *stop))block {
-//%  [self enumerate##ACCESSOR_NAME##ValuesWithOptions:0 usingBlock:block];
+//%  [self enumerate##ACCESSOR_NAME##ValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 //%}
 //%
 //%- (void)enumerate##ACCESSOR_NAME##ValuesWithOptions:(NSEnumerationOptions)opts
@@ -406,7 +406,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(int32_t value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -654,7 +654,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(uint32_t value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -902,7 +902,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(int64_t value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -1150,7 +1150,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(uint64_t value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -1398,7 +1398,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(float value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -1646,7 +1646,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(double value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -1894,7 +1894,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(BOOL value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts
@@ -2166,7 +2166,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateRawValuesWithBlock:(void (^)(int32_t value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateRawValuesWithOptions:0 usingBlock:block];
+  [self enumerateRawValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateRawValuesWithOptions:(NSEnumerationOptions)opts
@@ -2218,7 +2218,7 @@ static BOOL ArrayDefault_IsValidValue(int32_t value) {
 }
 
 - (void)enumerateValuesWithBlock:(void (^)(int32_t value, NSUInteger idx, BOOL *stop))block {
-  [self enumerateValuesWithOptions:0 usingBlock:block];
+  [self enumerateValuesWithOptions:(NSEnumerationOptions)0 usingBlock:block];
 }
 
 - (void)enumerateValuesWithOptions:(NSEnumerationOptions)opts

objectivec/GPBCodedOutputStream.m

@@ -290,7 +290,7 @@ static void GPBWriteRawLittleEndian64(GPBOutputBufferState *state,
                      maxLength:bufferBytesLeft
                     usedLength:&usedBufferLength
                       encoding:NSUTF8StringEncoding
-                       options:0
+                       options:(NSStringEncodingConversionOptions)0
                          range:NSMakeRange(0, [value length])
                 remainingRange:NULL];
     }

objectivec/GPBDescriptor_PackagePrivate.h

@@ -37,6 +37,7 @@
 
 // Describes attributes of the field.
 typedef NS_OPTIONS(uint16_t, GPBFieldFlags) {
+  GPBFieldNone            = 0,
   // These map to standard protobuf concepts.
   GPBFieldRequired        = 1 << 0,
   GPBFieldRepeated        = 1 << 1,
@@ -111,6 +112,7 @@ typedef struct GPBMessageFieldDescriptionWithDefault {
 
 // Describes attributes of the extension.
 typedef NS_OPTIONS(uint8_t, GPBExtensionOptions) {
+  GPBExtensionNone          = 0,
   // These map to standard protobuf concepts.
   GPBExtensionRepeated      = 1 << 0,
   GPBExtensionPacked        = 1 << 1,
@@ -130,6 +132,7 @@ typedef struct GPBExtensionDescription {
 } GPBExtensionDescription;
 
 typedef NS_OPTIONS(uint32_t, GPBDescriptorInitializationFlags) {
+  GPBDescriptorInitializationFlag_None              = 0,
   GPBDescriptorInitializationFlag_FieldsWithDefault = 1 << 0,
   GPBDescriptorInitializationFlag_WireFormat        = 1 << 1,
 };

objectivec/ProtocolBuffers_OSX.xcodeproj/project.pbxproj

@@ -782,6 +782,7 @@
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_RAND = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_STRCPY = YES;
 				CLANG_STATIC_ANALYZER_MODE = deep;
+				CLANG_WARN_ASSIGN_ENUM = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_NULLABLE_TO_NONNULL_CONVERSION = YES;
@@ -842,6 +843,7 @@
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_RAND = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_STRCPY = YES;
 				CLANG_STATIC_ANALYZER_MODE = deep;
+				CLANG_WARN_ASSIGN_ENUM = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_NULLABLE_TO_NONNULL_CONVERSION = YES;

objectivec/ProtocolBuffers_iOS.xcodeproj/project.pbxproj

@@ -944,6 +944,7 @@
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_RAND = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_STRCPY = YES;
 				CLANG_STATIC_ANALYZER_MODE = deep;
+				CLANG_WARN_ASSIGN_ENUM = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_NULLABLE_TO_NONNULL_CONVERSION = YES;
@@ -1005,6 +1006,7 @@
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_RAND = YES;
 				CLANG_ANALYZER_SECURITY_INSECUREAPI_STRCPY = YES;
 				CLANG_STATIC_ANALYZER_MODE = deep;
+				CLANG_WARN_ASSIGN_ENUM = YES;
 				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
 				CLANG_WARN_NULLABLE_TO_NONNULL_CONVERSION = YES;

objectivec/google/protobuf/Any.pbobjc.m

@@ -71,7 +71,7 @@ typedef struct GPBAny__storage_ {
         .number = GPBAny_FieldNumber_TypeURL,
         .hasIndex = 0,
         .offset = (uint32_t)offsetof(GPBAny__storage_, typeURL),
-        .flags = GPBFieldOptional | GPBFieldTextFormatNameCustom,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldTextFormatNameCustom),
         .dataType = GPBDataTypeString,
       },
       {
@@ -91,7 +91,7 @@ typedef struct GPBAny__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBAny__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
 #if !GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS
     static const char *extraTextFormatInfo =
         "\001\001\004\241!!\000";

objectivec/google/protobuf/Api.pbobjc.m

@@ -139,7 +139,7 @@ typedef struct GPBApi__storage_ {
         .number = GPBApi_FieldNumber_Syntax,
         .hasIndex = 3,
         .offset = (uint32_t)offsetof(GPBApi__storage_, syntax),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
     };
@@ -150,7 +150,7 @@ typedef struct GPBApi__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBApi__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -213,7 +213,7 @@ typedef struct GPBMethod__storage_ {
         .number = GPBMethod_FieldNumber_RequestTypeURL,
         .hasIndex = 1,
         .offset = (uint32_t)offsetof(GPBMethod__storage_, requestTypeURL),
-        .flags = GPBFieldOptional | GPBFieldTextFormatNameCustom,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldTextFormatNameCustom),
         .dataType = GPBDataTypeString,
       },
       {
@@ -231,7 +231,7 @@ typedef struct GPBMethod__storage_ {
         .number = GPBMethod_FieldNumber_ResponseTypeURL,
         .hasIndex = 4,
         .offset = (uint32_t)offsetof(GPBMethod__storage_, responseTypeURL),
-        .flags = GPBFieldOptional | GPBFieldTextFormatNameCustom,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldTextFormatNameCustom),
         .dataType = GPBDataTypeString,
       },
       {
@@ -258,7 +258,7 @@ typedef struct GPBMethod__storage_ {
         .number = GPBMethod_FieldNumber_Syntax,
         .hasIndex = 7,
         .offset = (uint32_t)offsetof(GPBMethod__storage_, syntax),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
     };
@@ -269,7 +269,7 @@ typedef struct GPBMethod__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBMethod__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
 #if !GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS
     static const char *extraTextFormatInfo =
         "\002\002\007\244\241!!\000\004\010\244\241!!\000";
@@ -340,7 +340,7 @@ typedef struct GPBMixin__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBMixin__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/Duration.pbobjc.m

@@ -91,7 +91,7 @@ typedef struct GPBDuration__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBDuration__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/Empty.pbobjc.m

@@ -67,7 +67,7 @@ typedef struct GPBEmpty__storage_ {
                                         fields:NULL
                                     fieldCount:0
                                    storageSize:sizeof(GPBEmpty__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/FieldMask.pbobjc.m

@@ -80,7 +80,7 @@ typedef struct GPBFieldMask__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBFieldMask__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/SourceContext.pbobjc.m

@@ -80,7 +80,7 @@ typedef struct GPBSourceContext__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBSourceContext__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/Struct.pbobjc.m

@@ -113,7 +113,7 @@ typedef struct GPBStruct__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBStruct__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -155,7 +155,7 @@ typedef struct GPBValue__storage_ {
         .number = GPBValue_FieldNumber_NullValue,
         .hasIndex = -1,
         .offset = (uint32_t)offsetof(GPBValue__storage_, nullValue),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
       {
@@ -211,7 +211,7 @@ typedef struct GPBValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     static const char *oneofs[] = {
       "kind",
     };
@@ -277,7 +277,7 @@ typedef struct GPBListValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBListValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/Timestamp.pbobjc.m

@@ -91,7 +91,7 @@ typedef struct GPBTimestamp__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBTimestamp__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/Type.pbobjc.m

@@ -162,7 +162,7 @@ typedef struct GPBType__storage_ {
         .number = GPBType_FieldNumber_Syntax,
         .hasIndex = 2,
         .offset = (uint32_t)offsetof(GPBType__storage_, syntax),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
     };
@@ -173,7 +173,7 @@ typedef struct GPBType__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBType__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -234,7 +234,7 @@ typedef struct GPBField__storage_ {
         .number = GPBField_FieldNumber_Kind,
         .hasIndex = 0,
         .offset = (uint32_t)offsetof(GPBField__storage_, kind),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
       {
@@ -243,7 +243,7 @@ typedef struct GPBField__storage_ {
         .number = GPBField_FieldNumber_Cardinality,
         .hasIndex = 1,
         .offset = (uint32_t)offsetof(GPBField__storage_, cardinality),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
       {
@@ -270,7 +270,7 @@ typedef struct GPBField__storage_ {
         .number = GPBField_FieldNumber_TypeURL,
         .hasIndex = 4,
         .offset = (uint32_t)offsetof(GPBField__storage_, typeURL),
-        .flags = GPBFieldOptional | GPBFieldTextFormatNameCustom,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldTextFormatNameCustom),
         .dataType = GPBDataTypeString,
       },
       {
@@ -326,7 +326,7 @@ typedef struct GPBField__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBField__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
 #if !GPBOBJC_SKIP_MESSAGE_TEXTFORMAT_EXTRAS
     static const char *extraTextFormatInfo =
         "\001\006\004\241!!\000";
@@ -543,7 +543,7 @@ typedef struct GPBEnum__storage_ {
         .number = GPBEnum_FieldNumber_Syntax,
         .hasIndex = 2,
         .offset = (uint32_t)offsetof(GPBEnum__storage_, syntax),
-        .flags = GPBFieldOptional | GPBFieldHasEnumDescriptor,
+        .flags = (GPBFieldFlags)(GPBFieldOptional | GPBFieldHasEnumDescriptor),
         .dataType = GPBDataTypeEnum,
       },
     };
@@ -554,7 +554,7 @@ typedef struct GPBEnum__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBEnum__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -631,7 +631,7 @@ typedef struct GPBEnumValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBEnumValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -685,7 +685,7 @@ typedef struct GPBOption__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBOption__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

objectivec/google/protobuf/Wrappers.pbobjc.m

@@ -80,7 +80,7 @@ typedef struct GPBDoubleValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBDoubleValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -123,7 +123,7 @@ typedef struct GPBFloatValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBFloatValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -166,7 +166,7 @@ typedef struct GPBInt64Value__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBInt64Value__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -209,7 +209,7 @@ typedef struct GPBUInt64Value__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBUInt64Value__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -252,7 +252,7 @@ typedef struct GPBInt32Value__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBInt32Value__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -295,7 +295,7 @@ typedef struct GPBUInt32Value__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBUInt32Value__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -337,7 +337,7 @@ typedef struct GPBBoolValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBBoolValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -380,7 +380,7 @@ typedef struct GPBStringValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBStringValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }
@@ -423,7 +423,7 @@ typedef struct GPBBytesValue__storage_ {
                                         fields:fields
                                     fieldCount:(uint32_t)(sizeof(fields) / sizeof(GPBMessageFieldDescription))
                                    storageSize:sizeof(GPBBytesValue__storage_)
-                                         flags:0];
+                                         flags:GPBDescriptorInitializationFlag_None];
     NSAssert(descriptor == nil, @"Startup recursed!");
     descriptor = localDescriptor;
   }

src/google/protobuf/compiler/objectivec/objectivec_extension.cc

@@ -85,7 +85,7 @@ void ExtensionGenerator::GenerateStaticVariablesInitialization(
   if (descriptor_->containing_type()->options().message_set_wire_format())
     options.push_back("GPBExtensionSetWireFormat");
 
-  vars["options"] = BuildFlagsString(options);
+  vars["options"] = BuildFlagsString(FLAGTYPE_EXTENSION, options);
 
   ObjectiveCType objc_type = GetObjectiveCType(descriptor_);
   string singular_type;

src/google/protobuf/compiler/objectivec/objectivec_field.cc

@@ -93,7 +93,7 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
     field_flags.push_back("GPBFieldHasEnumDescriptor");
   }
 
-  (*variables)["fieldflags"] = BuildFlagsString(field_flags);
+  (*variables)["fieldflags"] = BuildFlagsString(FLAGTYPE_FIELD, field_flags);
 
   (*variables)["default"] = DefaultValue(descriptor);
   (*variables)["default_name"] = GPBGenericValueFieldName(descriptor);

src/google/protobuf/compiler/objectivec/objectivec_helpers.cc

@@ -262,6 +262,34 @@ bool IsSpecialName(const string& name, const string* special_names,
   return false;
 }
 
+string GetZeroEnumNameForFlagType(const FlagType flag_type) {
+  switch(flag_type) {
+    case FLAGTYPE_DESCRIPTOR_INITIALIZATION:
+      return "GPBDescriptorInitializationFlag_None";
+    case FLAGTYPE_EXTENSION:
+      return "GPBExtensionNone";
+    case FLAGTYPE_FIELD:
+      return "GPBFieldNone";
+    default:
+      GOOGLE_LOG(FATAL) << "Can't get here.";
+      return "0";
+  }
+}
+
+string GetEnumNameForFlagType(const FlagType flag_type) {
+  switch(flag_type) {
+    case FLAGTYPE_DESCRIPTOR_INITIALIZATION:
+      return "GPBDescriptorInitializationFlags";
+    case FLAGTYPE_EXTENSION:
+      return "GPBExtensionOptions";
+    case FLAGTYPE_FIELD:
+      return "GPBFieldFlags";
+    default:
+      GOOGLE_LOG(FATAL) << "Can't get here.";
+      return string();
+  }
+}
+
 }  // namespace
 
 // Escape C++ trigraphs by escaping question marks to \?
@@ -817,17 +845,21 @@ bool HasNonZeroDefaultValue(const FieldDescriptor* field) {
   return false;
 }
 
-string BuildFlagsString(const vector<string>& strings) {
+string BuildFlagsString(const FlagType flag_type,
+                        const vector<string>& strings) {
   if (strings.size() == 0) {
-    return "0";
+    return GetZeroEnumNameForFlagType(flag_type);
+  } else if (strings.size() == 1) {
+    return strings[0];
   }
-  string string;
+  string string("(" + GetEnumNameForFlagType(flag_type) + ")(");
   for (size_t i = 0; i != strings.size(); ++i) {
     if (i > 0) {
       string.append(" | ");
     }
     string.append(strings[i]);
   }
+  string.append(")");
   return string;
 }
 

src/google/protobuf/compiler/objectivec/objectivec_helpers.h

@@ -137,6 +137,12 @@ enum ObjectiveCType {
   OBJECTIVECTYPE_MESSAGE
 };
 
+enum FlagType {
+  FLAGTYPE_DESCRIPTOR_INITIALIZATION,
+  FLAGTYPE_EXTENSION,
+  FLAGTYPE_FIELD
+};
+
 template<class TDescriptor>
 string GetOptionalDeprecatedAttribute(const TDescriptor* descriptor, bool preSpace = true, bool postNewline = false) {
   if (descriptor->options().deprecated()) {
@@ -168,7 +174,7 @@ string GPBGenericValueFieldName(const FieldDescriptor* field);
 string DefaultValue(const FieldDescriptor* field);
 bool HasNonZeroDefaultValue(const FieldDescriptor* field);
 
-string BuildFlagsString(const vector<string>& strings);
+string BuildFlagsString(const FlagType type, const vector<string>& strings);
 
 // Builds HeaderDoc/appledoc style comments out of the comments in the .proto
 // file.

src/google/protobuf/compiler/objectivec/objectivec_map_field.cc

@@ -115,7 +115,7 @@ MapFieldGenerator::MapFieldGenerator(const FieldDescriptor* descriptor,
   if (value_field_flags.find("GPBFieldHasEnumDescriptor") != string::npos) {
     field_flags.push_back("GPBFieldHasEnumDescriptor");
   }
-  variables_["fieldflags"] = BuildFlagsString(field_flags);
+  variables_["fieldflags"] = BuildFlagsString(FLAGTYPE_FIELD, field_flags);
 
   ObjectiveCType value_objc_type = GetObjectiveCType(value_descriptor);
   const bool value_is_object_type =

src/google/protobuf/compiler/objectivec/objectivec_message.cc

@@ -521,7 +521,8 @@ void MessageGenerator::GenerateSource(io::Printer* printer) {
     if (descriptor_->options().message_set_wire_format()) {
       init_flags.push_back("GPBDescriptorInitializationFlag_WireFormat");
     }
-    vars["init_flags"] = BuildFlagsString(init_flags);
+    vars["init_flags"] = BuildFlagsString(FLAGTYPE_DESCRIPTOR_INITIALIZATION,
+                                          init_flags);
 
     printer->Print(
         vars,