[ECO-5117][RTL13a] Fixed channel ATTACHING event detach err

1. Updated `attachWithTimeout` and `attachImpl` method to accept msgError param
2. Updated test assertions for spec RTL13a accordingly

Author: sacOO7

lib/src/main/java/io/ably/lib/realtime/ChannelBase.java

@@ -194,7 +194,7 @@ public void attach(CompletionListener listener) throws  AblyException {
 
     void attach(boolean forceReattach, CompletionListener listener) {
         clearAttachTimers();
-        attachWithTimeout(forceReattach, listener);
+        attachWithTimeout(forceReattach, listener, null);
     }
 
     /**
@@ -217,7 +217,7 @@ synchronized void transferQueuedPresenceMessages(List<QueuedMessage> messagesToT
 
     private boolean attachResume;
 
-    private void attachImpl(final boolean forceReattach, final CompletionListener listener) throws AblyException {
+    private void attachImpl(final boolean forceReattach, final CompletionListener listener, ErrorInfo reattachmentReason) throws AblyException {
         Log.v(TAG, "attach(); channel = " + name);
         if(!forceReattach) {
             /* check preconditions */
@@ -249,7 +249,7 @@ private void attachImpl(final boolean forceReattach, final CompletionListener li
             if (listener != null) {
                 on(new ChannelStateCompletionListener(listener, ChannelState.attached, ChannelState.failed));
             }
-            setState(ChannelState.attaching, null);
+            setState(ChannelState.attaching, reattachmentReason);
             return;
         }
 
@@ -277,7 +277,7 @@ private void attachImpl(final boolean forceReattach, final CompletionListener li
                 attachMessage.setFlag(Flag.attach_resume);
             }
 
-            setState(ChannelState.attaching, null);
+            setState(ChannelState.attaching, reattachmentReason);
             connectionManager.send(attachMessage, true, null);
         } catch(AblyException e) {
             throw e;
@@ -470,14 +470,14 @@ synchronized private void clearAttachTimers() {
     }
 
     private void attachWithTimeout(final CompletionListener listener) throws AblyException {
-        this.attachWithTimeout(false, listener);
+        this.attachWithTimeout(false, listener, null);
     }
 
     /**
      * Attach channel, if not attached within timeout set state to suspended and
      * set up timer to reattach it later
      */
-    synchronized private void attachWithTimeout(final boolean forceReattach, final CompletionListener listener) {
+    synchronized private void attachWithTimeout(final boolean forceReattach, final CompletionListener listener, ErrorInfo reattachmentReason) {
         checkChannelIsNotReleased();
         Timer currentAttachTimer;
         try {
@@ -502,7 +502,7 @@ public void onError(ErrorInfo reason) {
                     clearAttachTimers();
                     callCompletionListenerError(listener, reason);
                 }
-            });
+            }, reattachmentReason);
         } catch(AblyException e) {
             attachTimer = null;
             callCompletionListenerError(listener, e.errorInfo);
@@ -1303,7 +1303,7 @@ void onChannelMessage(ProtocolMessage msg) {
                 case suspended:
                     /* Unexpected detach, reattach immediately as per RTL13a */
                     Log.v(TAG, String.format(Locale.ROOT, "Server initiated detach for channel %s; attempting reattach", name));
-                    attachWithTimeout(true, null);
+                    attachWithTimeout(true, null, msg.error);
                     break;
                 case attaching:
                     /* RTL13b says we need to be suspended, but continue to retry */

lib/src/test/java/io/ably/lib/test/realtime/RealtimeChannelTest.java

@@ -1813,11 +1813,16 @@ public void server_initiated_detach_for_attached_channel() throws AblyException
             ProtocolMessage detachedMessage = new ProtocolMessage() {{
                 action = Action.detached;
                 channel = channelName;
+                error = new ErrorInfo("Simulated detach", 40000);
             }};
             ably.connection.connectionManager.onMessage(null, detachedMessage);
 
             /* Channel should transition to attaching, then to attached */
-            channelWaiter.waitFor(ChannelState.attaching);
+            ErrorInfo detachErr = channelWaiter.waitFor(ChannelState.attaching);
+            Assert.assertNotNull(detachErr);
+            Assert.assertEquals(40000, detachErr.code);
+            Assert.assertEquals("Simulated detach", detachErr.message);
+
             channelWaiter.waitFor(ChannelState.attached);
 
             List<ChannelState> channelStates = channelWaiter.getRecordedStates();
@@ -1869,11 +1874,16 @@ public void server_initiated_detach_for_suspended_channel() throws AblyException
             ProtocolMessage detachedMessage = new ProtocolMessage() {{
                 action = Action.detached;
                 channel = channelName;
+                error = new ErrorInfo("Simulated detach", 40000);
             }};
             ably.connection.connectionManager.onMessage(null, detachedMessage);
 
             /* Channel should transition to attaching, then to attached */
-            channelWaiter.waitFor(ChannelState.attaching);
+            ErrorInfo detachError = channelWaiter.waitFor(ChannelState.attaching);
+            Assert.assertNotNull(detachError);
+            Assert.assertEquals(40000, detachError.code);
+            Assert.assertEquals("Simulated detach", detachError.message);
+
             channelWaiter.waitFor(ChannelState.attached);
 
             List<ChannelState> channelStates = channelWaiter.getRecordedStates();