fix: missing "user left" system message after omnichannel room forward

[KevLehman]

Proposed changes (including videos or screenshots)

When an omnichannel room is forwarded (agent, department, or department fallback), RoutingManager.removeAllRoomSubscriptions removed each agent subscription with a fire-and-forget void removeAgentFromSubscription(...) inside a forEach. The ul (user left) system message written inside that call was never awaited by any caller, so it raced the rest of the transfer flow: the message could be persisted only after the transfer had already completed and the endpoint had responded. Anything reading the room history right after the transfer — like the LIVECHAT - rooms livechat/room.forward system messages sent on transfer should be properly generated API test — could intermittently see 0 ul messages, making that test flaky. It also allowed the message to land out of order relative to the transfer system messages.

Changes:

• Await each removeAgentFromSubscription call (iterating the cursor directly) so the ul message is persisted before the transfer flow returns, and failures surface instead of being swallowed by the floating promise
• Project only u from the subscriptions query, which is all the removal needs

Issue(s)

Steps to test or reproduce

1. Create two departments with online agents, forward a livechat room from one to the other (livechat/room.forward)
2. Fetch the room message history immediately — the previous agent's ul system message is now always already present

Further comments

The fire-and-forget dates back to the Fibers-era JS, where the call was effectively synchronous; the TS conversion added void to silence lint, making the race explicit but unhandled.

Task: CORE-2449

Summary by CodeRabbit

• Bug Fixes
  • Fixed conversation forwarding so the “user left” system message appears in the correct order within conversation history.
  • Improved subscription removal handling to ensure agent removals complete reliably during room cleanup.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 56dcabe

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@rocket.chat/meteor	Patch
@rocket.chat/core-typings	Patch
@rocket.chat/rest-typings	Patch

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[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 02302924-f1ac-41a1-af16-2b55c8fa28c7

📥 Commits

Reviewing files that changed from the base of the PR and between 8d8cd01 and 56dcabe.

📒 Files selected for processing (2)

• .changeset/livechat-forward-ul-message.md
• apps/meteor/server/lib/omnichannel/RoutingManager.ts

📜 Recent review details

⏰ Context from checks skipped due to timeout. (7)

• GitHub Check: cubic · AI code reviewer
• GitHub Check: Hacktron Security Check
• GitHub Check: 🔨 Test UI (EE) / MongoDB 8.0 coverage (5/5)
• GitHub Check: 🔨 Test UI (CE) / MongoDB 8.0 (4/4)
• GitHub Check: 🔨 Test UI (CE) / MongoDB 8.0 (1/4)
• GitHub Check: 🔨 Test UI (EE) / MongoDB 8.0 coverage (3/5)
• GitHub Check: 🔨 Test UI (EE) / MongoDB 8.0 coverage (4/5)

🧰 Additional context used

📓 Path-based instructions (1)

**/*.{ts,tsx,js}

📄 CodeRabbit inference engine (.cursor/rules/playwright.mdc)

**/*.{ts,tsx,js}: Write concise, technical TypeScript/JavaScript with accurate typing in Playwright tests
Avoid code comments in the implementation

Files:

• apps/meteor/server/lib/omnichannel/RoutingManager.ts

🧠 Learnings (4)

📚 Learning: 2026-03-16T21:50:37.589Z

Learnt from: amitb0ra
Repo: RocketChat/Rocket.Chat PR: 39676
File: .changeset/migrate-users-register-openapi.md:3-3
Timestamp: 2026-03-16T21:50:37.589Z
Learning: For changes related to OpenAPI migrations in Rocket.Chat/OpenAPI, when removing endpoint types and validators from rocket.chat/rest-typings (e.g., UserRegisterParamsPOST, /v1/users.register) document this as a minor changeset (not breaking) per RocketChat/Rocket.Chat-Open-API#150 Rule 7. Note that the endpoint type is re-exposed via a module augmentation .d.ts in the consuming package (e.g., packages/web-ui-registration/src/users-register.d.ts). In reviews, ensure the changeset clearly states: this is a non-breaking change, the major version should not be bumped, and the changeset reflects a minor version bump. Do not treat this as a breaking change during OpenAPI migrations.

Applied to files:

• .changeset/livechat-forward-ul-message.md

📚 Learning: 2026-02-26T19:25:44.063Z

Learnt from: gabriellsh
Repo: RocketChat/Rocket.Chat PR: 38778
File: packages/ui-voip/src/providers/useMediaSession.ts:192-192
Timestamp: 2026-02-26T19:25:44.063Z
Learning: In the Rocket.Chat repository, do not reference Biome lint rules in code review feedback. Biome is not used even if biome.json exists; only reference Biome rules if there is explicit, project-wide usage documented. For TypeScript files, review lint implications without Biome guidance unless the project enables Biome rules.

Applied to files:

• apps/meteor/server/lib/omnichannel/RoutingManager.ts

📚 Learning: 2026-02-26T19:25:44.063Z

Learnt from: gabriellsh
Repo: RocketChat/Rocket.Chat PR: 38778
File: packages/ui-voip/src/providers/useMediaSession.ts:192-192
Timestamp: 2026-02-26T19:25:44.063Z
Learning: In this repository (RocketChat/Rocket.Chat), Biome lint rules are not used even if a biome.json exists. When reviewing TypeScript files (e.g., packages/ui-voip/src/providers/useMediaSession.ts), ensure lint suggestions do not reference Biome-specific rules. Rely on general ESLint/TypeScript lint rules and project conventions instead.

Applied to files:

• apps/meteor/server/lib/omnichannel/RoutingManager.ts

📚 Learning: 2026-05-06T12:21:44.083Z

Learnt from: juliajforesti
Repo: RocketChat/Rocket.Chat PR: 40256
File: apps/meteor/client/components/CreateDiscussion/CreateDiscussion.tsx:121-149
Timestamp: 2026-05-06T12:21:44.083Z
Learning: Field wrappers in rocket.chat/fuselage-forms (Field, FieldLabel, FieldRow, FieldError, FieldHint) auto-create htmlFor/id associations, aria-describedby, and role="alert" for errors. Do not manually set htmlFor, id, aria-describedby, or role attributes when using these wrappers. This automatic wiring does not apply to plain rocket.chat/fuselage components, which require explicit ID wiring per the accessibility docs. In code reviews, prefer using fuselage-forms wrappers for form fields and verify there is no unnecessary manual ID/aria wiring in files that use these wrappers. If a component uses plain fuselage components, ensure proper id wiring as per docs.

Applied to files:

• apps/meteor/server/lib/omnichannel/RoutingManager.ts

🔇 Additional comments (2)

apps/meteor/server/lib/omnichannel/RoutingManager.ts (1)

374-379: LGTM!

.changeset/livechat-forward-ul-message.md (1)

1-5: LGTM!

---

Walkthrough

Changes

Omnichannel forwarding

Layer / File(s)	Summary
Await room subscription removal apps/meteor/server/lib/omnichannel/RoutingManager.ts, .changeset/livechat-forward-ul-message.md	removeAllRoomSubscriptions now processes subscriptions asynchronously and awaits each removal while preserving ignored-user filtering. The changeset records the patch and the message-order fix.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested labels: type: bug

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main fix: the missing or delayed "user left" message after omnichannel room forwarding.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Warning

Review ran into problems

🔥 Problems

Errors were encountered while retrieving linked issues.

Errors (1)

• CORE-2449: Request failed with status code 401

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 68.59%. Comparing base (b0ecca0) to head (56dcabe).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop   #41480      +/-   ##
===========================================
- Coverage    68.62%   68.59%   -0.03%     
===========================================
  Files         4134     4134              
  Lines       160801   160802       +1     
  Branches     29247    29267      +20     
===========================================
- Hits        110342   110299      -43     
- Misses       45353    45398      +45     
+ Partials      5106     5105       -1     

Flag	Coverage Δ
e2e	58.86% <ø> (-0.01%)	⬇️
e2e-api	45.34% <100.00%> (-0.02%)	⬇️
unit	70.54% <ø> (-0.05%)	⬇️

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[KevLehman]

/jira CORE

[cubic-dev-ai]

No issues found across 2 files

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