Ignore stale replies

Summary: Changelog: ignore stale replies

Reviewed By: lblasa

Differential Revision: D32829739

fbshipit-source-id: 267f43f8e8f3dea60ee86187f7a7709fea09e5af

desktop/flipper-server-core/src/comms/BrowserServerWebSocket.tsx

@@ -97,6 +97,11 @@ class BrowserServerWebSocket extends SecureServerWebSocket {
           // Upon initialization it sent a `getPlugins` request.
           // We find that request and resolve it with the list of plugins we received from the `connect` message
           const getPluginsCallbacks = clientConnection.matchPendingRequest(0);
+
+          if (!getPluginsCallbacks) {
+            return;
+          }
+
           getPluginsCallbacks.resolve({
             success: {plugins},
             length: rawMessage.length,

desktop/flipper-server-core/src/comms/SecureServerWebSocket.tsx

@@ -86,6 +86,10 @@ class SecureServerWebSocket extends ServerWebSocket {
     if (isWsResponseMessage(parsedMessage)) {
       const callbacks = clientConnection.matchPendingRequest(parsedMessage.id);
 
+      if (!callbacks) {
+        return;
+      }
+
       if (parsedMessage.success !== undefined) {
         callbacks.resolve({
           ...parsedMessage,

desktop/flipper-server-core/src/comms/WebSocketClientConnection.tsx

@@ -37,11 +37,14 @@ export default class WebSocketClientConnection implements ClientConnection {
     });
   }
 
-  matchPendingRequest(id: number): PendingRequestResolvers {
+  matchPendingRequest(id: number): PendingRequestResolvers | undefined {
     const callbacks = this.pendingRequests.get(id);
 
     if (!callbacks) {
-      throw new Error('Pending request was not found');
+      console.debug(`[conn] Pending request ${id} is not found. Ignore.`);
+      // It must be a response for a message from the older connection. Ignore.
+      // TODO: When we decide to bump sdk_version, make `id` a string equal to `connectionId:messageId`. Ignore messages only from other conections. Raise an error for missing mesages from this connection.
+      return;
     }
 
     this.pendingRequests.delete(id);