Only retry ViewCommand mount items if exception is marked as "Retryable"

Summary:
Instead of just blindly retrying all ViewCommands if they fail - which could be dangerous, since it's arbitrary imperative commands we'd be executing twice, potentially with bad app state - we only retry if the ViewCommand throws a "RetryableMountingLayerException".

Changelog: [Internal] Optimization to ViewCommands

Reviewed By: mdvacca

Differential Revision: D20529985

fbshipit-source-id: 0217b43f4bf92442bcc7ca48c8ae2b9a9e543dc9

ReactAndroid/src/main/java/com/facebook/react/bridge/ReactNoCrashSoftException.java

@@ -13,11 +13,15 @@ package com.facebook.react.bridge;
  * and not crash, no matter what.
  */
 public class ReactNoCrashSoftException extends RuntimeException {
-  public ReactNoCrashSoftException(String detailMessage) {
+  public ReactNoCrashSoftException(String m) {
-    super(detailMessage);
+    super(m);
   }
 
-  public ReactNoCrashSoftException(String detailMessage, Throwable ex) {
+  public ReactNoCrashSoftException(Throwable e) {
-    super(detailMessage, ex);
+    super(e);
+  }
+
+  public ReactNoCrashSoftException(String m, Throwable e) {
+    super(m, e);
   }
 }

ReactAndroid/src/main/java/com/facebook/react/bridge/RetryableMountingLayerException.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+package com.facebook.react.bridge;
+
+/**
+ * ViewCommands can throw this Exception. If this is caught during the execution of a ViewCommand
+ * mounting instruction, it indicates that the mount item can be safely retried.
+ */
+public class RetryableMountingLayerException extends RuntimeException {
+  public RetryableMountingLayerException(String msg, Throwable e) {
+    super(msg, e);
+  }
+
+  public RetryableMountingLayerException(Throwable e) {
+    super(e);
+  }
+
+  public RetryableMountingLayerException(String msg) {
+    super(msg);
+  }
+}

ReactAndroid/src/main/java/com/facebook/react/uimanager/NativeViewHierarchyManager.java

@@ -26,6 +26,7 @@ import com.facebook.react.bridge.JSApplicationIllegalArgumentException;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
+import com.facebook.react.bridge.RetryableMountingLayerException;
 import com.facebook.react.bridge.SoftAssertions;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.config.ReactFeatureFlags;
@@ -762,7 +763,7 @@ public class NativeViewHierarchyManager {
     UiThreadUtil.assertOnUiThread();
     View view = mTagsToViews.get(reactTag);
     if (view == null) {
-      throw new IllegalViewOperationException(
+      throw new RetryableMountingLayerException(
           "Trying to send command to a non-existing view with tag ["
               + reactTag
               + "] and command "
@@ -777,7 +778,7 @@ public class NativeViewHierarchyManager {
     UiThreadUtil.assertOnUiThread();
     View view = mTagsToViews.get(reactTag);
     if (view == null) {
-      throw new IllegalViewOperationException(
+      throw new RetryableMountingLayerException(
           "Trying to send command to a non-existing view with tag ["
               + reactTag
               + "] and command "

ReactAndroid/src/main/java/com/facebook/react/uimanager/UIViewOperationQueue.java

@@ -17,9 +17,11 @@ import com.facebook.react.bridge.Callback;
 import com.facebook.react.bridge.GuardedRunnable;
 import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
+import com.facebook.react.bridge.ReactNoCrashSoftException;
 import com.facebook.react.bridge.ReactSoftException;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
+import com.facebook.react.bridge.RetryableMountingLayerException;
 import com.facebook.react.bridge.SoftAssertions;
 import com.facebook.react.bridge.UiThreadUtil;
 import com.facebook.react.common.ReactConstants;
@@ -878,27 +880,26 @@ public class UIViewOperationQueue {
                   for (DispatchCommandViewOperation op : viewCommandOperations) {
                     try {
                       op.executeWithExceptions();
-                    } catch (Throwable e) {
+                    } catch (RetryableMountingLayerException e) {
                       // Catch errors in DispatchCommands. We allow all commands to be retried
-                      // exactly
+                      // exactly once, after the current batch of other mountitems. If the second
-                      // once, after the current batch of other mountitems. If the second attempt
+                      // attempt fails, then  we log a soft error. This will still crash only in
-                      // fails,
+                      // debug. We do this because it is a ~relatively common pattern to dispatch a
-                      // then  we log a soft error. This will still crash only in debug.
+                      // command during render, for example, to scroll to the bottom of a ScrollView
-                      // We do this because it is a ~relatively common pattern to dispatch a command
+                      // in render. This dispatches the command before that View is even mounted. By
-                      // during render, for example, to scroll to the bottom of a ScrollView in
+                      // retrying once, we can still dispatch the vast majority of commands faster,
-                      // render.
+                      // avoid errors, and still operate correctly for most commands even when
-                      // This dispatches the command before that View is even mounted. By retrying
+                      // they're executed too soon.
-                      // once,
-                      // we can still dispatch the vast majority of commands faster, avoid errors,
-                      // and
-                      // still operate correctly for most commands even when they're executed too
-                      // soon.
                       if (op.getRetries() == 0) {
                         op.incrementRetries();
                         mViewCommandOperations.add(op);
                       } else {
-                        ReactSoftException.logSoftException(TAG, e);
+                        // Retryable exceptions should be logged, but never crash in debug.
+                        ReactSoftException.logSoftException(TAG, new ReactNoCrashSoftException(e));
                       }
+                    } catch (Throwable e) {
+                      // Non-retryable exceptions should be logged in prod, and crash in Debug.
+                      ReactSoftException.logSoftException(TAG, e);
                     }
                   }
                 }

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java

@@ -9,9 +9,11 @@ package com.facebook.react.views.scroll;
 
 import android.graphics.Color;
 import android.util.DisplayMetrics;
+import android.view.View;
 import androidx.annotation.Nullable;
 import androidx.core.view.ViewCompat;
 import com.facebook.react.bridge.ReadableArray;
+import com.facebook.react.bridge.RetryableMountingLayerException;
 import com.facebook.react.common.MapBuilder;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
@@ -272,8 +274,13 @@ public class ReactScrollViewManager extends ViewGroupManager<ReactScrollView>
   @Override
   public void scrollToEnd(
       ReactScrollView scrollView, ReactScrollViewCommandHelper.ScrollToEndCommandData data) {
+    View child = scrollView.getChildAt(0);
+    if (child == null) {
+      throw new RetryableMountingLayerException("scrollToEnd called on ScrollView without child");
+    }
+
     // ScrollView always has one child - the scrollable area
-    int bottom = scrollView.getChildAt(0).getHeight() + scrollView.getPaddingBottom();
+    int bottom = child.getHeight() + scrollView.getPaddingBottom();
     if (data.mAnimated) {
       scrollView.reactSmoothScrollTo(scrollView.getScrollX(), bottom);
     } else {