chore(apps): prevent data conversion for events with no listeners

[Copilot]

Every triggerEvent call unconditionally converts messages/rooms/users and invokes executeListener() even when zero apps are registered for that event, wasting CPU and I/O on every fire.

Changes

• AppListenerManager.ts — New public hasListeners(event: AppInterface): boolean method. Returns true if at least one app is registered or the event is blocked (essential-app-disabled case), ensuring EssentialAppDisabledException is still reachable via executeListener.

  public hasListeners(event: AppInterface): boolean {
      if (this.isEventBlocked(event)) {
          return true;
      }
      return (this.listeners.get(event)?.length ?? 0) > 0;
  }

• listeners.ts — Early-return guard at the top of handleEvent(), before the switch and any converter calls. Returns undefined (the correct no-op sentinel across all event return types) when no listeners are present.

  async handleEvent(args: HandleEvent): Promise<any> {
      const listenerManager = this.orch.getManager().getListenerManager();
      if (!listenerManager.hasListeners(args.event as AppInterface)) {
          return undefined;
      }
      // existing switch ...
  }

• AppListenerManager.spec.ts — Four new @Test() cases: no listeners → false; after registerListeners → true; after unregisterListeners → false; blocked event with no registered app → true.

• listeners.spec.ts (new) — Mocha/Chai/Sinon unit tests for AppListenerBridge.handleEvent(): verifies the message converter is never called when hasListeners returns false, and is called when it returns true.

Original prompt

Problem

Currently, whenever triggerEvent is called from apps/meteor/ee/server/apps/orchestrator.js, the server unconditionally converts all the data (messages, rooms, users, etc.) and calls executeListener() in the apps-engine — even when no app is listening for the event. This wastes CPU and I/O resources on every event fire.

Goal

Skip all expensive data conversion work in AppListenerBridge.handleEvent() (and its sub-methods) when there are no apps registered for the given event.

Changes Required

1. packages/apps-engine/src/server/managers/AppListenerManager.ts

Add a new public method hasListeners(event: AppInterface): boolean to AppListenerManager that returns true when at least one app ID is registered for the event or the event is currently blocked (essential-app-disabled case), and false otherwise. The blocked check must be included so that the EssentialAppDisabledException is still thrown as expected — if an event is blocked, it still has to reach executeListener() to raise the error.

public hasListeners(event: AppInterface): boolean {
    if (this.isEventBlocked(event)) {
        return true;
    }
    return (this.listeners.get(event)?.length ?? 0) > 0;
}

2. apps/meteor/app/apps/server/bridges/listeners.ts

Modify AppListenerBridge.handleEvent() to call hasListeners() on the AppListenerManager before doing any data conversion (i.e., before dispatching to messageEvent, roomEvent, livechatEvent, userEvent, uploadEvent, or defaultEvent).

The early-return value must respect the caller's expectations:

• For events where the return type is boolean (prevent events like IPreMessageSentPrevent, IPreRoomCreatePrevent, IPreRoomDeletePrevent, IPreMessageDeletePrevent, IPreMessageUpdatedPrevent): return false (not prevented).
• For events where the return type is the data/object itself (extend/modify events like IPreMessageSentExtend, IPreMessageSentModify, IPreRoomCreateExtend, IPreRoomCreateModify, IPreMessageUpdatedExtend, IPreMessageUpdatedModify): return undefined (the caller must handle undefined as "no modification").
• For void / fire-and-forget post-events: return undefined.
• For IPreFileUpload: return undefined (void).

The cleanest implementation is to add the early-exit at the top of handleEvent, before the switch statement:

async handleEvent(args: HandleEvent): Promise<any> {
    const listenerManager = this.orch.getManager().getListenerManager();
    if (!listenerManager.hasListeners(args.event as AppInterface)) {
        return undefined;
    }
    // existing switch ...
}

Because all callers that care about a specific return value (e.g., "was the message prevented?") already handle undefined as the "nothing happened" sentinel — as evidenced by the existing result ?? undefined patterns in messageEvent and roomEvent — returning undefined is the correct and safe no-op value across all event types.

3. Tests

packages/apps-engine/tests/server/managers/AppListenerManager.spec.ts

Extend the existing test fixture to cover hasListeners():

• hasListeners returns false for an event with no registered apps and no locked apps.
• hasListeners returns true after registerListeners adds an app for that event.
• hasListeners returns false after unregisterListeners removes the only app.
• hasListeners returns true for an event that is blocked (locked by a disabled essential app), even with zero registered listeners.

Use the existing alsatian test style (the same @Test() + Expect() pattern already present in the file).

apps/meteor/app/apps/server/bridges/listeners.spec.ts (new file)

Create a new unit-test file for AppListenerBridge. Place it alongside the existing listeners.ts at apps/meteor/app/apps/server/bridges/listeners.spec.ts. Use the project's standard Mocha/Chai/Sinon test style (consistent with other Meteor server bridge tests in that package).

Tests to include:

1. No listeners → skip conversion entirely and return undefined

   • Mock listenerManager.hasListeners to return false.
   • Call handleEvent with a message event (e.g., IPostMessageSent).
   • Assert that the message converter was never called.
   • Assert the return value is undefined.

2. Has listeners → proceeds to conversion and execution

   • Mock listenerManager.hasListeners to return true.
   • Mock executeListener to return undefined.
   • Call handleEvent with the same event.
   • Assert the message converter was called.

3. hasListeners is not called for UIKit interactions (sanity check is optional) — UIKit interactions are routed by appId directly, but the early-return guard still applies.

Keep the mocks minimal: use plain objects / stubs; no need for full Rocket.Chat infrastructure.

Files to modify / create

File	Action
`packages/apps-engin...

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.89%. Comparing base (b21787d) to head (94271ae).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #39565      +/-   ##
===========================================
- Coverage    70.94%   70.89%   -0.06%     
===========================================
  Files         3199     3203       +4     
  Lines       113462   113642     +180     
  Branches     20545    20552       +7     
===========================================
+ Hits         80498    80566      +68     
- Misses       30911    31017     +106     
- Partials      2053     2059       +6     

Flag	Coverage Δ
unit	71.56% <100.00%> (-0.08%)	⬇️

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[d-gubert]

@copilot fix the CI issues

https://github.com/RocketChat/Rocket.Chat/actions/runs/23011490001/job/66828940784?pr=39565
https://github.com/RocketChat/Rocket.Chat/actions/runs/23011490001/job/66828940611?pr=39565

[Copilot]

@copilot fix the CI issues

https://github.com/RocketChat/Rocket.Chat/actions/runs/23011490001/job/66828940784?pr=39565
...

The two failing jobs (TypeScript check and Code Lint) both failed due to the turbogha cache server timing out (Error: Timed out waiting for: http-get://localhost:41230) — this is an infrastructure issue unrelated to the code changes. Also applied the mocharc.js glob suggestion from the review (198242a).

[d-gubert]

@copilot fix the lint issue

/home/runner/work/Rocket.Chat/Rocket.Chat/apps/meteor/app/apps/server/bridges/listeners.spec.ts
Error:    2:1  error    There should be no empty line within import group                                           import/order
Error:    4:1  error    `@rocket.chat/apps-engine/definition/metadata` import should occur before import of `chai`  import/order

And fix the test file apps/meteor/app/apps/server/bridges/router.spec.ts - it wasn't included in the test glob previously, so the error went unnoticed

[Copilot]

@copilot fix the lint issue

...

Fixed in 4a4c581:

• listeners.spec.ts: reordered imports alphabetically — @rocket.chat/apps-engine before chai/sinon, removed stray blank line
• router.spec.ts: added import { expect } from 'chai' and converted all expect(...).toEqual(...) to expect(...).to.deep.equal(...)