Use the containing class name instead of the class object to improve robustness for linker dead code removal with extension registration and extension lookup in different frameworks (where the class could be removed in the registering framework)

PiperOrigin-RevId: 862228896

Author: stefanhaustein

protobuf/runtime/src/com/google/protobuf/Descriptors.m

@@ -30,6 +30,7 @@
 
 //  Hand written counterpart of com.google.protobuf.Descriptors.
 
+#import <Foundation/Foundation.h>
 #import "com/google/protobuf/Descriptors_PackagePrivate.h"
 
 #import "IOSClass.h"
@@ -90,8 +91,9 @@ size_t CGPGetTypeSize(CGPFieldJavaType type) {
       type:ComGoogleProtobufDescriptors_FieldDescriptor_class_()];
   CGPFieldDescriptor **fieldsBuf = fields->buffer_;
   for (jint i = 0; i < fieldCount; i++) {
-    fieldsBuf[i] = [[CGPFieldDescriptor alloc] initWithData:&fieldData[i]
-                                             containingType:containingType];
+    fieldsBuf[i] =
+        [[CGPFieldDescriptor alloc] initWithData:&fieldData[i]
+                                  containingType:NSStringFromClass([containingType class])];
   }
   return fields;
 }
@@ -354,8 +356,7 @@ static void CGPFieldFixDefaultValue(CGPFieldDescriptor *descriptor) {
   }
 }
 
-- (instancetype)initWithData:(CGPFieldData *)data
-              containingType:(CGPDescriptor *)containingType {
+- (instancetype)initWithData:(CGPFieldData *)data containingType:(NSString *)containingType {
   if (self = [self init]) {
     data_ = data;
     tag_ = TagFromData(data);

protobuf/runtime/src/com/google/protobuf/Descriptors_PackagePrivate.h

@@ -122,12 +122,11 @@ typedef struct CGPOneofData {
   // Either nil, a Descriptor or a EnumDescriptor depending on the field type.
   id valueType_;
   ComGoogleProtobufDescriptorProtos_FieldOptions *fieldOptions_;
-  CGPDescriptor *containingType_;
+  NSString *containingType_;
   CGPOneofDescriptor *containingOneof_;
 }
 
-- (instancetype)initWithData:(CGPFieldData *)data
-              containingType:(CGPDescriptor *)containingType;
+- (instancetype)initWithData:(CGPFieldData *)data containingType:(NSString *)containingType;
 
 @end
 

protobuf/runtime/src/com/google/protobuf/ExtensionLite.m

@@ -59,11 +59,9 @@ - (CGPFieldDescriptor *)getDescriptor {
 void ComGoogleProtobufExtensionLite_initWithFieldData_(CGPExtensionLite *self,
                                                        struct CGPFieldData *data) {
   NSObject_init(self);
-  Class msgClass = objc_getClass(data->containingType);
-  NSCAssert(msgClass != nil, @"Containing message type not found.");
-  CGPDescriptor *containingType = [msgClass performSelector:@selector(getDescriptor)];
-  self->fieldDescriptor_ =
-      [[CGPFieldDescriptor alloc] initWithData:data containingType:containingType];
+  self->fieldDescriptor_ = [[CGPFieldDescriptor alloc]
+        initWithData:data
+      containingType:[NSString stringWithUTF8String:data->containingType]];
 }
 
 J2OBJC_CLASS_TYPE_LITERAL_SOURCE(ComGoogleProtobufExtensionLite)

protobuf/runtime/src/com/google/protobuf/ExtensionRegistryLite.mm

@@ -37,7 +37,7 @@
 
 #include "J2ObjC_source.h"
 
-typedef std::pair<const CGPDescriptor *, jint> ExtensionRegistryKey;
+typedef std::pair<std::string, jint> ExtensionRegistryKey;
 typedef std::map<ExtensionRegistryKey, CGPFieldDescriptor *> ExtensionRegistryMap;
 
 @interface ComGoogleProtobufExtensionRegistryLite () {
@@ -90,8 +90,8 @@ + (void)initialize {
 
 void CGPExtensionRegistryAdd(CGPExtensionRegistryLite *registry, CGPExtensionLite *extension) {
   CGPFieldDescriptor *field = extension->fieldDescriptor_;
-  CGPDescriptor *containingType = field->containingType_;
-  registry->map_[ExtensionRegistryKey(containingType, CGPFieldGetNumber(field))] = field;
+  registry->map_[ExtensionRegistryKey(std::string(field->containingType_.UTF8String),
+                                      CGPFieldGetNumber(field))] = field;
 }
 
 void ComGoogleProtobufExtensionRegistryLite_initWithBoolean_(
@@ -109,7 +109,8 @@ void ComGoogleProtobufExtensionRegistryLite_initWithBoolean_(
 CGPFieldDescriptor *CGPExtensionRegistryFind(
     CGPExtensionRegistryLite *registry, CGPDescriptor *descriptor, jint fieldNumber) {
   ExtensionRegistryMap *map = &registry->map_;
-  ExtensionRegistryMap::iterator it = map->find(ExtensionRegistryKey(descriptor, fieldNumber));
+  ExtensionRegistryMap::iterator it = map->find(ExtensionRegistryKey(
+      std::string(NSStringFromClass([descriptor->messageClass_ class]).UTF8String), fieldNumber));
   if (it != map->end()) {
     return it->second;
   }