Improve idle timer and connection state log messages

Add connection ID, error codes, and actionable context to connection
lifecycle log messages. The idle timer expiry now explains what will
happen next (disconnect + reconnect) and includes the error
code 80003. A new LOG_MINOR message logs when the connection is
resumed or reestablished after disconnection, providing a bookend to
the idle expiry message. The connection state freshness check now
explains consequences (new connection, channel reattach) and includes
the connection state TTL and connection ID. Also replace "realtime"
with "Ably" in user-facing log messages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mattheworiordan

src/common/lib/transport/connectionmanager.ts

@@ -644,6 +644,7 @@ class ConnectionManager extends EventEmitter {
     this.activeProtocol = new Protocol(transport);
     this.host = transport.params.host;
 
+    const prevConnId = this.connectionId;
     const connectionKey = connectionDetails.connectionKey;
     if (connectionKey && this.connectionKey != connectionKey) {
       this.setConnection(connectionId, connectionDetails, !!error);
@@ -673,6 +674,19 @@ class ConnectionManager extends EventEmitter {
         this.emit('update', new ConnectionStateChange(connectedState, connectedState, null, error));
       }
     } else {
+      if (existingState.state === this.states.disconnected.state) {
+        const resumed = prevConnId === connectionId;
+        Logger.logAction(
+          this.logger,
+          Logger.LOG_MINOR,
+          'ConnectionManager.activateTransport()',
+          'Connection ' +
+            (resumed ? 'resumed' : 'reestablished') +
+            ' after disconnection; connectionId: ' +
+            connectionId +
+            (prevConnId && !resumed ? ' (previously: ' + prevConnId + ')' : ''),
+        );
+      }
       this.notifyState({ state: 'connected', error: error });
       this.errorReason = this.realtime.connection.errorReason = error || null;
     }
@@ -876,7 +890,13 @@ class ConnectionManager extends EventEmitter {
         this.logger,
         Logger.LOG_MINOR,
         'ConnectionManager.checkConnectionStateFreshness()',
-        'Last known activity from realtime was ' + sinceLast + 'ms ago; discarding connection state',
+        'Last known activity from Ably was ' +
+          sinceLast +
+          'ms ago (exceeds freshness threshold of ' +
+          (this.connectionStateTtl + (this.maxIdleInterval as number)) +
+          'ms); discarding connection state. ' +
+          'A new connection will be established and channels will reattach' +
+          (this.connectionId ? '; connectionId: ' + this.connectionId : ''),
       );
       this.clearConnection();
       this.states.connecting.failState = 'suspended';

src/common/lib/transport/transport.ts

@@ -290,7 +290,14 @@ abstract class Transport extends EventEmitter {
     const sinceLast = Date.now() - this.lastActivity;
     const timeRemaining = this.maxIdleInterval - sinceLast;
     if (timeRemaining <= 0) {
-      const msg = 'No activity seen from realtime in ' + sinceLast + 'ms; assuming connection has dropped';
+      const connId = this.connectionManager.connectionId;
+      const msg =
+        'No activity seen from Ably in ' +
+        sinceLast +
+        'ms; assuming connection has dropped. ' +
+        'Will disconnect and reconnect automatically (error code: 80003, status: 408' +
+        (connId ? ', connectionId: ' + connId : '') +
+        ')';
       Logger.logAction(this.logger, Logger.LOG_ERROR, 'Transport.onIdleTimerExpire()', msg);
       this.disconnect(new ErrorInfo(msg, 80003, 408));
     } else {