fix: improve channel options reattachment logic

This internal change makes the client more selective about which options
provided to `channels.get` will be interpreted as requiring
reattachment. More precisely, the channel params and modes will now be
shallow compared to existing params and modes, and only if they differ
will the call the `chnanels.get` throw an error (, provided of course
that the channel is already attached or attaching).

src/common/lib/client/realtimechannel.ts

@@ -185,7 +185,20 @@ class RealtimeChannel extends Channel {
   }
 
   _shouldReattachToSetOptions(options?: API.Types.ChannelOptions) {
-    return (this.state === 'attached' || this.state === 'attaching') && (options?.params || options?.modes);
+    if (!(this.state === 'attached' || this.state === 'attaching')) {
+      return false;
+    }
+    if (options?.params) {
+      if (!this.params || !Utils.shallowEquals(this.params, options.params)) {
+        return true;
+      }
+    }
+    if (options?.modes) {
+      if (!this.modes || !Utils.arrEquals(options.modes, this.modes)) {
+        return true;
+      }
+    }
+    return false;
   }
 
   publish(...args: any[]): void | Promise<void> {

test/realtime/channel.test.js

@@ -647,7 +647,9 @@ define(['ably', 'shared_helper', 'async', 'chai'], function (Ably, helper, async
 
             try {
               realtime.channels.get(testName, {
-                params: params,
+                params: {
+                  modes: 'subscribe',
+                },
               });
             } catch (err) {
               try {
@@ -714,7 +716,9 @@ define(['ably', 'shared_helper', 'async', 'chai'], function (Ably, helper, async
                   var setOptionsReturned = false;
                   channel.setOptions(
                     {
-                      params: params,
+                      params: {
+                        modes: 'publish',
+                      },
                     },
                     function () {
                       /* Wait a tick so we don' depend on whether the update event runs the
@@ -743,7 +747,7 @@ define(['ably', 'shared_helper', 'async', 'chai'], function (Ably, helper, async
                   var setOptionsReturned = false;
                   channel.setOptions(
                     {
-                      modes: modes,
+                      modes: ['subscribe'],
                     },
                     function () {
                       Ably.Realtime.Platform.Config.nextTick(function () {