Add experimental feature of hierarchyDisplayDidFinish being recursive (#2123)

* Add experimental feature of hierarchyDisplayDidFinish being recursive

## Summary

`hierarchyDisplayDidFinish` is currently called when a node's immediate subnodes implement custom CALayer rendering. For example, ASNetworkImageNode and ASTextNode perform this sort of rendering. However, it can be useful -- and less fragile -- if `hierarchyDisplayDidFinish` is propagated further up the node hierarchy. That way, if a feature is refactored such that an extra node appears between the node implementing `hierarchyDisplayDidFinish` and the nodes doing CALayer rendering, we don't lose the callback.

## Test plan

Manually tested using a modified version of the Kittens example. Also ran `build.sh tests`.

* Revert SDK change since it's still Xcode 15

Author: andyfinnell

.ruby-version

@@ -1 +1 @@
-3.3.0
+3.3.8

Source/ASDisplayNode+Beta.h

@@ -122,6 +122,7 @@ typedef struct {
  * and other nodes that are ready to do their final display). Each render of every progressive jpeg network node would cause this to be called, so
  * this hook could be called up to 1 + (pJPEGcount * pJPEGrenderCount) times. The render count depends on how many times the downloader calls the
  * progressImage block.
+ * @note This is only called when immediate children implement custom CALayer rendering. To propagate beyond immediate supernode, turn on ASExperimentalHierarchyDisplayDidFinishIsRecursive
  */
 AS_CATEGORY_IMPLEMENTABLE
 - (void)hierarchyDisplayDidFinish NS_REQUIRES_SUPER;

Source/ASDisplayNode.mm

@@ -1318,21 +1318,22 @@ - (BOOL)_implementsDisplay
 
 // Track that a node will be displayed as part of the current node hierarchy.
 // The node sending the message should usually be passed as the parameter, similar to the delegation pattern.
-- (void)_pendingNodeWillDisplay:(ASDisplayNode *)node
+- (BOOL)_pendingNodeWillDisplay:(ASDisplayNode *)node
 {
   ASDisplayNodeAssertMainThread();
 
   // No lock needed as _pendingDisplayNodes is main thread only
   if (!_pendingDisplayNodes) {
     _pendingDisplayNodes = [[ASWeakSet alloc] init];
   }
-
+  BOOL wasEmpty = [_pendingDisplayNodes isEmpty];
   [_pendingDisplayNodes addObject:node];
+  return wasEmpty;
 }
 
 // Notify that a node that was pending display finished
 // The node sending the message should usually be passed as the parameter, similar to the delegation pattern.
-- (void)_pendingNodeDidDisplay:(ASDisplayNode *)node
+- (BOOL)_pendingNodeDidDisplay:(ASDisplayNode *)node
 {
   ASDisplayNodeAssertMainThread();
 
@@ -1367,6 +1368,10 @@ - (void)_pendingNodeDidDisplay:(ASDisplayNode *)node
       }
     }
     __instanceLock__.unlock();
+    
+    return YES;
+  } else {
+    return NO;
   }
 }
 
@@ -1768,13 +1773,29 @@ - (void)displayDidFinish
 - (void)subnodeDisplayWillStart:(ASDisplayNode *)subnode
 {
   // Subclass hook
-  [self _pendingNodeWillDisplay:subnode];
+  BOOL didAddFirstOne = [self _pendingNodeWillDisplay:subnode];
+  
+  if (didAddFirstOne && ASActivateExperimentalFeature(ASExperimentalHierarchyDisplayDidFinishIsRecursive)) {
+    __instanceLock__.lock();
+    ASDisplayNode *supernode = _supernode;
+    __instanceLock__.unlock();
+    
+    [supernode subnodeDisplayWillStart:self];
+  }
 }
 
 - (void)subnodeDisplayDidFinish:(ASDisplayNode *)subnode
 {
   // Subclass hook
-  [self _pendingNodeDidDisplay:subnode];
+  BOOL didRemoveLastOne = [self _pendingNodeDidDisplay:subnode];
+  
+  if (didRemoveLastOne && ASActivateExperimentalFeature(ASExperimentalHierarchyDisplayDidFinishIsRecursive)) {
+    __instanceLock__.lock();
+    ASDisplayNode *supernode = _supernode;
+    __instanceLock__.unlock();
+    
+    [supernode subnodeDisplayDidFinish:self];
+  }
 }
 
 #pragma mark <CALayerDelegate>

Source/ASExperimentalFeatures.h

@@ -33,6 +33,7 @@ typedef NS_OPTIONS(NSUInteger, ASExperimentalFeatures) {
   ASExperimentalRangeUpdateOnChangesetUpdate = 1 << 12,                     // exp_range_update_on_changeset_update
   ASExperimentalNoTextRendererCache = 1 << 13,                              // exp_no_text_renderer_cache
   ASExperimentalLockTextRendererCache = 1 << 14,                            // exp_lock_text_renderer_cache
+  ASExperimentalHierarchyDisplayDidFinishIsRecursive = 1 << 15,             // exp_hierarchy_display_did_finish_is_recursive
   ASExperimentalFeatureAll = 0xFFFFFFFF
 };
 

Source/ASExperimentalFeatures.mm

@@ -26,7 +26,8 @@
                                       @"exp_main_thread_only_data_controller",
                                       @"exp_range_update_on_changeset_update",
                                       @"exp_no_text_renderer_cache",
-                                      @"exp_lock_text_renderer_cache"]));
+                                      @"exp_lock_text_renderer_cache",
+                                      @"exp_hierarchy_display_did_finish_is_recursive"]));
 
   if (flags == ASExperimentalFeatureAll) {
     return allNames;