From 9ddc038e547eafc48b71195634dad210882149f6 Mon Sep 17 00:00:00 2001
From: Joshua Gross <joshuagross@fb.com>
Date: Sat, 19 Oct 2019 02:27:35 -0700
Subject: [PATCH] WebSocketModule should verify that Catalyst is alive before
 getting a JS module

Summary:
WebSocketModule can be called asynchronously while the ReactContext/CatalystInstance is being torn down. Trying to get a JS module at this time will result in a crash if the ReactContext has already torn down Catalyst. Check explicitly that Catalyst is still alive before trying to emit an event to JS via some JS module.

Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D18020359

fbshipit-source-id: 1b77abd457c7d97bd241389251890bb682b6fde3
---
 .../modules/websocket/WebSocketModule.java    | 21 ++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.java b/ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.java
index 4ab4d2e99db..6684d9e33b5 100644
--- a/ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.java
+++ b/ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.java
@@ -7,6 +7,7 @@
 
 package com.facebook.react.modules.websocket;
 
+import android.util.Log;
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
 import com.facebook.react.bridge.Arguments;
@@ -14,12 +15,14 @@ import com.facebook.react.bridge.ReactApplicationContext;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.ReactContextBaseJavaModule;
 import com.facebook.react.bridge.ReactMethod;
+import com.facebook.react.bridge.ReactSoftException;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.ReadableMapKeySetIterator;
 import com.facebook.react.bridge.ReadableType;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.common.ReactConstants;
+import com.facebook.react.common.build.ReactBuildConfig;
 import com.facebook.react.module.annotations.ReactModule;
 import com.facebook.react.modules.core.DeviceEventManagerModule;
 import com.facebook.react.modules.network.ForwardingCookieHandler;
@@ -61,9 +64,21 @@ public final class WebSocketModule extends ReactContextBaseJavaModule {
   }
 
   private void sendEvent(String eventName, WritableMap params) {
-    mReactContext
-        .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
-        .emit(eventName, params);
+    if (mReactContext.hasActiveCatalystInstance()) {
+      mReactContext
+          .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
+          .emit(eventName, params);
+    } else {
+      // We want to collect data about how often this happens, but raising a SoftException in Debug
+      // will cause a crash, which isn't desirable.
+      String msg =
+          "sendEvent: trying to update app state when Catalyst Instance has already disappeared";
+      if (ReactBuildConfig.DEBUG) {
+        Log.e(NAME, msg);
+      } else {
+        ReactSoftException.logSoftException(NAME, new IllegalStateException(msg));
+      }
+    }
   }
 
   @Override