add more logs to ReactViewGroup dispatchDraw and onViewRemoved

Author: SzymczakJ

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/view/ReactViewGroup.java

@@ -141,6 +141,13 @@ public void shutdown() {
   private @Nullable Set<Integer> mChildrenRemovedWhileTransitioning;
   private boolean mPreventClipping;
 
+  // debug values that will allow us to track down the source of the NPEs, related task: https://app.asana.com/1/236888843494340/project/1211388770903360/task/1211036733309341
+  private static final String[] removalTrackedChildrenIDs = {
+          "native-freeze-screens-container",
+          "guilds-bar-fast-list",
+  };
+
+
   /**
    * Creates a new `ReactViewGroup` instance.
    *
@@ -641,6 +648,25 @@ public void onViewAdded(View child) {
 
   @Override
   public void onViewRemoved(View child) {
+    try {
+      Object childNativeId = child.getTag(R.id.view_tag_native_id);
+      if (nativeId instanceof String) {
+        String nativeID = (String) nativeId;
+        boolean matches = java.util.Arrays.stream(removalTrackedChildrenIDs)
+                .anyMatch(nativeID::equals);
+        if (matches) {
+          StringBuilder stackTraceBuilder = new StringBuilder();
+          for (StackTraceElement element : new Exception().getStackTrace()) {
+            stackTraceBuilder.append("\n    at ").append(element.toString());
+          }
+          String stackTrace = stackTraceBuilder.toString();
+          FLog.e(ReactConstants.TAG, "onViewRemoved of one of the tracked children: " + nativeID + " with stack trace: " + "\n" + stackTrace);
+        }
+      }
+    } catch (Exception e) {
+      FLog.e(ReactConstants.TAG, "Exception in getting onViewRemoved info: " + e.getMessage());
+    }
+
     UiThreadUtil.assertOnUiThread();
     checkViewClippingTag(child, Boolean.TRUE);
     if (!customDrawOrderDisabled()) {
@@ -999,17 +1025,20 @@ protected void dispatchDraw(Canvas canvas) {
     if (mOverflow != Overflow.VISIBLE || getTag(R.id.filter) != null) {
       BackgroundStyleApplicator.clipToPaddingBox(this, canvas);
     }
-    
+
     try {
       super.dispatchDraw(canvas);
     } catch (NullPointerException e) {
+      String childrenCountInfo = "children count info: mAllChildrenCount:" + mAllChildrenCount + " getChildCount: " + getChildCount();
+      String childrenViewInfo = describeChildren();
       String ancestry = null;
       try {
         ancestry = describeViewAncestry(this);
       } catch (Throwable ignore) {}
-      FLog.e(TAG, "NullPointerException in dispatchDraw of " + getClass().getName() + ": " + e.getMessage() + "\n" + ancestry);
+      FLog.e(TAG, "NullPointerException in dispatchDraw of " + e.getStackTrace() + getClass().getName() + ": " + e.getMessage() + "\n Failing view ancestry: " + ancestry);
+      FLog.e(TAG, "Child info: \n" + childrenCountInfo + "\n" + childrenViewInfo);
       throw new NullPointerException(
-          "NullPointerException in dispatchDraw of " + getClass().getName() + ": " + e.getMessage() + "\n" + ancestry);
+          "NullPointerException in dispatchDraw of " + getClass().getName() + ": " + e.getMessage() + "\n" + e.getStackTrace());
     }
   }
 
@@ -1038,6 +1067,60 @@ private static String describeViewAncestry(View start) {
     return sb.toString();
   }
 
+  // Helper function to describe children for debugging
+  private String describeChildren() {
+    final StringBuilder sb = new StringBuilder();
+
+    sb.append("  Attached children: ");
+    int childCount = getChildCount();
+    if (childCount == 0) {
+      sb.append("    (none)\n");
+    } else {
+      for (int i = 0; i < childCount; i++) {
+        try {
+          View child = getChildAt(i);
+          if (child == null) {
+            sb.append("    [").append(i).append("] NULL CHILD!\n");
+          } else {
+            Object childNativeId = child.getTag(R.id.view_tag_native_id);
+            Object childTestId = child.getTag(R.id.react_test_id);
+            sb.append("    [").append(i).append("] ")
+                .append(child.getClass().getSimpleName())
+                .append(" id=").append(child.getId());
+            if (childNativeId != null) sb.append(" nativeID=").append(childNativeId);
+            if (childTestId != null) sb.append(" testID=").append(childTestId);
+            sb.append(" parent=").append(child.getParent() != null ? "attached" : "DETACHED");
+            sb.append('\n');
+          }
+        } catch (Exception e) {
+          sb.append("    [").append(i).append("] ERROR: ").append(e.getMessage()).append('\n');
+        }
+      }
+    }
+
+ try {
+    // If removeClippedSubviews is enabled, show clipped children too
+    if (mRemoveClippedSubviews && mAllChildren != null && mAllChildrenCount > childCount) {
+      sb.append("  Clipped children:\n");
+      for (int i = 0; i < mAllChildrenCount; i++) {
+        View child = mAllChildren[i];
+        if (child != null && child.getParent() == null) {
+          Object childNativeId = child.getTag(R.id.view_tag_native_id);
+          sb.append("    [").append(i).append("] ")
+              .append(child.getClass().getSimpleName())
+              .append(" id=").append(child.getId());
+          if (childNativeId != null) sb.append(" nativeID=").append(childNativeId);
+          sb.append(" (CLIPPED)\n");
+        }
+      }
+    }
+ } catch (Exception e) {
+  sb.append("  Error describing clipped children: ").append(e.getMessage()).append('\n');
+ }
+
+    return sb.toString();
+  }
+
   @Override
   protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
     boolean drawWithZ = child.getElevation() > 0;