Fix for play issue (#1223)

See https://github.com/jambonz/jambonz-feature-server/issues/1222

lib/session/call-session.js

@@ -83,6 +83,7 @@ class CallSession extends Emitter {
     this.stickyEventEmitter = new StickyEventEmitter();
     this.stickyEventEmitter.onSuccess = () => {
       this.taskInProgress = null;
+      this.stickyEventEmitter.destroy();
     };
     this.backgroundTaskManager = new BackgroundTaskManager({
       cs: this,
@@ -1927,10 +1928,12 @@ Duration=${duration} `
     this.stackIdx++;
     this.logger.debug({tasks: listTaskNames(tasks)},
       `CallSession:replaceApplication reset with ${tasks.length} new tasks, stack depth is ${this.stackIdx}`);
+    let curTaskKilled = false;
     if (this.currentTask) {
       this.logger.debug('CallSession:replaceApplication - killing current task ' +
         this.currentTask?.name + ', taskId: ' + this.currentTask.taskId);
       this.currentTask.kill(this, KillReason.Replaced);
+      curTaskKilled = true;
       this.currentTask = null;
     }
     else if (this.wakeupResolver) {
@@ -1938,7 +1941,8 @@ Duration=${duration} `
       this.wakeupResolver({reason: 'new tasks'});
       this.wakeupResolver = null;
     }
-    if ((!this.currentTask || this.currentTask === undefined) && this.isCurTaskPlay) {
+    // if currentTask which is play, already got killed, no need to call uuid_break
+    if (!curTaskKilled && (!this.currentTask || this.currentTask === undefined) && this.isCurTaskPlay) {
       this.logger.debug(`CallSession:replaceApplication - emitting uuid_break, taskId: ${this.taskInProgress?.taskId}`);
       this.stickyEventEmitter.emit('uuid_break', this.taskInProgress);
     }

lib/utils/sticky-event-emitter.js

@@ -37,6 +37,10 @@ class StickyEventEmitter extends EventEmitter {
         this.onSuccess();
       }
       this._onceListeners.delete(event);
+      // return from here as the event listener is already called
+      // this is to avoid calling the native emit method which
+      // will call the event listener again
+      return true;
     }
 
     return super.emit(event, ...args);