Address review comments.

Author: bzbarsky-apple

src/darwin/Framework/CHIP/ServerEndpoint/MTRServerAttribute.h

@@ -24,6 +24,8 @@ NS_ASSUME_NONNULL_BEGIN
  * A representation of an attribute implemented on a server cluster by an
  * MTRDeviceController.  An attribute has an identifier and a value, and may or
  * may not be writable.
+ *
+ * MTRServerAttribute's API can be accessed from any thread.
  */
 NS_SWIFT_SENDABLE
 MTR_NEWLY_AVAILABLE
@@ -51,13 +53,13 @@ MTR_NEWLY_AVAILABLE
  */
 - (BOOL)setValue:(NSDictionary<NSString *, id> *)value;
 
-@property (nonatomic, copy, readonly) NSNumber * attributeID;
-@property (nonatomic, copy, readonly) NSDictionary<NSString *, id> * value;
+@property (atomic, copy, readonly) NSNumber * attributeID;
+@property (atomic, copy, readonly) NSDictionary<NSString *, id> * value;
 /**
  * The privilege level necessary to read this attribute.
  */
-@property (nonatomic, assign, readonly) MTRAccessControlEntryPrivilege requiredReadPrivilege;
-@property (nonatomic, assign, readonly, getter=isWritable) BOOL writable;
+@property (atomic, assign, readonly) MTRAccessControlEntryPrivilege requiredReadPrivilege;
+@property (atomic, assign, readonly, getter=isWritable) BOOL writable;
 
 @end
 

src/darwin/Framework/CHIP/ServerEndpoint/MTRServerCluster.h

@@ -23,6 +23,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 /**
  * A representation of a server cluster implemented by an MTRDeviceController.
+ *
+ * MTRServerCluster's API can be accessed from any thread.
  */
 NS_SWIFT_SENDABLE
 MTR_NEWLY_AVAILABLE
@@ -90,22 +92,22 @@ MTR_NEWLY_AVAILABLE
  */
 + (MTRServerCluster *)newDescriptorCluster;
 
-@property (nonatomic, copy, readonly) NSNumber * clusterID;
+@property (atomic, copy, readonly) NSNumber * clusterID;
 
-@property (nonatomic, copy, readonly) NSNumber * clusterRevision;
+@property (atomic, copy, readonly) NSNumber * clusterRevision;
 
 /**
  * The list of entities that are allowed to access this cluster instance.  This
  * list is in addition to any endpoint-wide access grants that exist.
  *
  * Defaults to empty list, which means no additional access grants.
  */
-@property (nonatomic, copy, readonly) NSArray<MTRAccessGrant *> * accessGrants;
+@property (atomic, copy, readonly) NSArray<MTRAccessGrant *> * accessGrants;
 
 /**
  * The list of attributes supported by the cluster.
  */
-@property (nonatomic, copy, readonly) NSArray<MTRServerAttribute *> * attributes;
+@property (atomic, copy, readonly) NSArray<MTRServerAttribute *> * attributes;
 
 @end
 

src/darwin/Framework/CHIP/ServerEndpoint/MTRServerCluster.mm

@@ -88,10 +88,8 @@ @implementation MTRServerCluster {
     NSArray<NSNumber *> * _generatedCommands;
 
     /**
-     * _lock always protects access to: _accessGrants, _attributes,
-     * _deviceController, _attributeAccessInterface, _matterAttributeMetadata,
-     * _matterAccessGrants, _parentEndpoint, _acceptedCommands,
-     * _generatedCommands, _matterAcceptedCommandList, _matterGeneratedCommandList.
+     * _lock always protects access to all our mutable ivars (the ones that are
+     * modified after init).
      */
     os_unfair_lock _lock;
 }

src/darwin/Framework/CHIP/ServerEndpoint/MTRServerCluster_Internal.h

@@ -66,37 +66,37 @@ NS_ASSUME_NONNULL_BEGIN
  * The access grants the Matter stack can observe.  Only modified while
  * associating with a controller or on the Matter queue.
  */
-@property (nonatomic, copy, readonly) NSArray<MTRAccessGrant *> * matterAccessGrants;
+@property (atomic, copy, readonly) NSArray<MTRAccessGrant *> * matterAccessGrants;
 
 /**
  * parentEndpoint will be kInvalidEndpointId until the cluster is added to an endpoint.
  */
-@property (nonatomic, assign, readonly) chip::EndpointId parentEndpoint;
+@property (atomic, assign, readonly) chip::EndpointId parentEndpoint;
 
 /**
  * The attribute metadata for the cluster.  Only valid after associateWithController: has succeeded.
  */
-@property (nonatomic, assign, readonly) chip::Span<const EmberAfAttributeMetadata> matterAttributeMetadata;
+@property (atomic, assign, readonly) chip::Span<const EmberAfAttributeMetadata> matterAttributeMetadata;
 
 /**
  * The list of accepted command IDs.
  */
-@property (nonatomic, copy, nullable) NSArray<NSNumber *> * acceptedCommands;
+@property (atomic, copy, nullable) NSArray<NSNumber *> * acceptedCommands;
 
 /**
  * The list of generated command IDs.
  */
-@property (nonatomic, copy, nullable) NSArray<NSNumber *> * generatedCommands;
+@property (atomic, copy, nullable) NSArray<NSNumber *> * generatedCommands;
 
 /**
  * The list of accepted commands IDs in the format the Matter stack needs.
  */
-@property (nonatomic, assign, nullable, readonly) chip::CommandId * matterAcceptedCommands;
+@property (atomic, assign, nullable, readonly) chip::CommandId * matterAcceptedCommands;
 
 /**
  * The list of generated commands IDs in the format the Matter stack needs.
  */
-@property (nonatomic, assign, nullable, readonly) chip::CommandId * matterGeneratedCommands;
+@property (atomic, assign, nullable, readonly) chip::CommandId * matterGeneratedCommands;
 
 @end