Fix a bug with Yoga nodes whose position change and don't update. (#1408

)

Source/ASDisplayNode+Layout.mm

@@ -402,9 +402,19 @@ - (void)_u_measureNodeWithBoundsIfNecessary:(CGRect)bounds
     // Use the last known constrainedSize passed from a parent during layout (if never, use bounds).
     NSUInteger version = _layoutVersion;
     ASSizeRange constrainedSize = [self _locked_constrainedSizeForLayoutPass];
+#if YOGA
+    // This flag indicates to the Texture+Yoga code that this next layout is intended to be
+    // displayed (vs. just for measurement). This will cause it to call setNeedsLayout on any nodes
+    // whose layout changes as a result of the Yoga recalculation. This is necessary because a
+    // change in one Yoga node can change the layout for any other node in the tree.
+    self.willApplyNextYogaCalculatedLayout = YES;
+#endif
     ASLayout *layout = [self calculateLayoutThatFits:constrainedSize
                                     restrictedToSize:self.style.size
                                 relativeToParentSize:boundsSizeForLayout];
+#if YOGA
+    self.willApplyNextYogaCalculatedLayout = NO;
+#endif
     nextLayout = ASDisplayNodeLayout(layout, constrainedSize, boundsSizeForLayout, version);
     // Now that the constrained size of pending layout might have been reused, the layout is useless
     // Release it and any orphaned subnodes it retains

Source/ASDisplayNode+Yoga.h

@@ -29,6 +29,7 @@ AS_EXTERN void ASDisplayNodePerformBlockOnEveryYogaChild(ASDisplayNode * _Nullab
 @property BOOL yogaLayoutInProgress;
 // TODO: Make this atomic (lock).
 @property (nullable, nonatomic) ASLayout *yogaCalculatedLayout;
+@property (nonatomic) BOOL willApplyNextYogaCalculatedLayout;
 
 // Will walk up the Yoga tree and returns the root node
 - (ASDisplayNode *)yogaRoot;
@@ -54,7 +55,7 @@ AS_EXTERN void ASDisplayNodePerformBlockOnEveryYogaChild(ASDisplayNode * _Nullab
 /// For internal usage only
 - (ASLayout *)calculateLayoutYoga:(ASSizeRange)constrainedSize;
 /// For internal usage only
-- (void)calculateLayoutFromYogaRoot:(ASSizeRange)rootConstrainedSize;
+- (void)calculateLayoutFromYogaRoot:(ASSizeRange)rootConstrainedSize willApply:(BOOL)willApply;
 /// For internal usage only
 - (void)invalidateCalculatedYogaLayout;
 /**

Source/ASDisplayNode+Yoga.mm

@@ -166,6 +166,14 @@ - (ASLayout *)yogaCalculatedLayout
   return _yogaCalculatedLayout;
 }
 
+- (BOOL)willApplyNextYogaCalculatedLayout {
+  return _willApplyNextYogaCalculatedLayout;
+}
+
+- (void)setWillApplyNextYogaCalculatedLayout:(BOOL)willApplyNextYogaCalculatedLayout {
+  _willApplyNextYogaCalculatedLayout = willApplyNextYogaCalculatedLayout;
+}
+
 - (void)setYogaLayoutInProgress:(BOOL)yogaLayoutInProgress
 {
   setFlag(YogaLayoutInProgress, yogaLayoutInProgress);
@@ -194,7 +202,7 @@ - (ASLayout *)layoutForYogaNode
   return [ASLayout layoutWithLayoutElement:self size:size position:position sublayouts:nil];
 }
 
-- (void)setupYogaCalculatedLayout
+- (void)setupYogaCalculatedLayoutAndSetNeedsLayoutForChangedNodes:(BOOL)setNeedsLayoutForChangedNodes
 {
   ASScopedLockSelfOrToRoot();
 
@@ -231,6 +239,13 @@ - (void)setupYogaCalculatedLayout
   layout = [layout filteredNodeLayoutTree];
 
   if ([self.yogaCalculatedLayout isEqual:layout] == NO) {
+    if (setNeedsLayoutForChangedNodes && !self.willApplyNextYogaCalculatedLayout) {
+      // This flag will be set when this layout is intended for immediate display. In this case, we
+      // want to ensure that we call setNeedsLayout on any other nodes. Note that we skip any nodes
+      // whose willApplyNextYogaCalculatedLayout flags are set, as those are the nodes that are
+      // already being laid out.
+      [self setNeedsLayout];
+    }
     self.yogaCalculatedLayout = layout;
   } else {
     layout = self.yogaCalculatedLayout;
@@ -320,7 +335,7 @@ - (ASLayout *)calculateLayoutYoga:(ASSizeRange)constrainedSize
     if (self.yogaLayoutInProgress == NO) {
       ASYogaLog("Calculating yoga layout from root %@, %@", self,
               NSStringFromASSizeRange(constrainedSize));
-      [self calculateLayoutFromYogaRoot:constrainedSize];
+      [self calculateLayoutFromYogaRoot:constrainedSize willApply:self.willApplyNextYogaCalculatedLayout];
     } else {
       ASYogaLog("Reusing existing yoga layout %@", _yogaCalculatedLayout);
     }
@@ -337,15 +352,15 @@ - (ASLayout *)calculateLayoutYoga:(ASSizeRange)constrainedSize
   return [self calculateLayoutLayoutSpec:constrainedSize];
 }
 
-- (void)calculateLayoutFromYogaRoot:(ASSizeRange)rootConstrainedSize
+- (void)calculateLayoutFromYogaRoot:(ASSizeRange)rootConstrainedSize willApply:(BOOL)willApply
 {
   ASScopedLockSet lockSet = [self lockToRootIfNeededForLayout];
   ASDisplayNode *yogaRoot = self.yogaRoot;
 
   if (self != yogaRoot) {
     ASYogaLog("ESCALATING to Yoga root: %@", self);
     // TODO(appleguy): Consider how to get the constrainedSize for the yogaRoot when escalating manually.
-    [yogaRoot calculateLayoutFromYogaRoot:ASSizeRangeUnconstrained];
+    [yogaRoot calculateLayoutFromYogaRoot:ASSizeRangeUnconstrained willApply:willApply];
     return;
   }
 
@@ -398,7 +413,7 @@ - (void)calculateLayoutFromYogaRoot:(ASSizeRange)rootConstrainedSize
   });
 
   ASDisplayNodePerformBlockOnEveryYogaChild(self, ^(ASDisplayNode * _Nonnull node) {
-    [node setupYogaCalculatedLayout];
+    [node setupYogaCalculatedLayoutAndSetNeedsLayoutForChangedNodes:willApply];
     node.yogaLayoutInProgress = NO;
   });
 

Source/Private/ASDisplayNodeInternal.h

@@ -164,6 +164,7 @@ AS_EXTERN NSString * const ASRenderingEngineDidDisplayNodesScheduledBeforeTimest
   NSMutableArray<ASDisplayNode *> *_yogaChildren;
   __weak ASDisplayNode *_yogaParent;
   ASLayout *_yogaCalculatedLayout;
+  BOOL _willApplyNextYogaCalculatedLayout;
 #endif
 
   // Automatically manages subnodes