fix(settings): Skip pairing channel close once the socket is gone

packages/fxa-settings/src/lib/channels/pairing-channel.test.ts

@@ -21,6 +21,7 @@ let mockChannel: {
   removeEventListener: jest.Mock;
   _channelId?: string;
   _channelKey?: Uint8Array;
+  _connection?: unknown;
 };
 
 jest.mock(
@@ -250,6 +251,23 @@ describe('PairingChannelClient', () => {
       await expect(client.close()).resolves.toBeUndefined();
       expect(client.isConnected).toBe(false);
     });
+
+    // A socket error disconnects the channel without a matching `close` event,
+    // and the integrations tear down in response — so close() runs against a
+    // channel the package has already unwired.
+    it('skips the underlying close once the socket is gone', async () => {
+      await client.open(SERVER, CHAN, VALID_KEY);
+      getMockHandler('error')(
+        new CustomEvent('error', { detail: new Error('ws fail') })
+      );
+      mockChannel._connection = null;
+
+      await expect(client.close()).resolves.toBeUndefined();
+
+      expect(mockChannel.close).not.toHaveBeenCalled();
+      expect(mockChannel.removeEventListener).toHaveBeenCalled();
+      expect(client.isConnected).toBe(false);
+    });
   });
 
   describe('incoming messages', () => {

packages/fxa-settings/src/lib/channels/pairing-channel.ts

@@ -138,6 +138,11 @@ type PairingChannelSocket = {
   removeEventListener(type: string, listener: EventListener): void;
   _channelId?: string;
   _channelKey?: Uint8Array;
+  /**
+   * fxa-pairing-channel's own handle on the socket. It is nulled out when the
+   * socket goes away, and the package's `close()` dereferences it unguarded.
+   */
+  _connection?: unknown;
 };
 
 export class PairingChannelClient extends EventTarget {
@@ -275,6 +280,16 @@ export class PairingChannelClient extends EventTarget {
     const ch = this.channel;
     this.channel = null;
     this.removeChannelListeners(ch);
+
+    // An `error` from the socket leaves the channel disconnected without a
+    // matching `close`, so teardown still arrives here holding a dead channel.
+    // There is no socket left to shut down, and asking the package to close one
+    // throws. An absent `_connection` is not the same signal as a null one:
+    // only null means the package has torn the socket down.
+    if (ch._connection === null) {
+      return;
+    }
+
     try {
       console.info('Closing channel ', ch._channelId)
       await ch.close();