Learnt from: smirk-dev
Repo: RocketChat/Rocket.Chat PR: 39625
File: apps/meteor/app/api/server/v1/push.ts:85-97
Timestamp: 2026-03-14T14:58:58.834Z
Learning: In RocketChat/Rocket.Chat, the `push.token` POST/DELETE endpoints in `apps/meteor/app/api/server/v1/push.ts` were already migrated to the chained router API pattern on `develop` prior to PR `#39625`. `cleanTokenResult` (which strips `authToken` and returns `PushTokenResult`) and `isPushTokenPOSTProps`/`isPushTokenDELETEProps` validators already exist on `develop`. PR `#39625` only migrates `push.get` and `push.info` to the chained pattern. Do not flag `cleanTokenResult` or `PushTokenResult` as newly introduced behavior-breaking changes when reviewing this PR.

Learnt from: ggazzo
Repo: RocketChat/Rocket.Chat PR: 35995
File: apps/meteor/app/api/server/v1/rooms.ts:1107-1112
Timestamp: 2026-02-23T17:53:18.785Z
Learning: In Rocket.Chat PR reviews, maintain strict scope boundaries—when a PR is focused on a specific endpoint (e.g., rooms.favorite), avoid reviewing or suggesting changes to other endpoints that were incidentally refactored (e.g., rooms.invite) unless explicitly requested by maintainers.

Learnt from: ahmed-n-abdeltwab
Repo: RocketChat/Rocket.Chat PR: 0
File: :0-0
Timestamp: 2026-02-24T19:05:56.710Z
Learning: Rocket.Chat repo context: When a workspace manifest on develop already pins a dependency version (e.g., packages/web-ui-registration → "rocket.chat/ui-contexts": "27.0.1"), a lockfile change in a feature PR that upgrades only that dependency’s resolution is considered a manifest-driven sync and can be kept, preferably as a small "chore: sync yarn.lock with manifests" commit.

Learnt from: ahmed-n-abdeltwab
Repo: RocketChat/Rocket.Chat PR: 38974
File: apps/meteor/app/api/server/v1/im.ts:220-221
Timestamp: 2026-02-24T19:09:09.561Z
Learning: In RocketChat/Rocket.Chat OpenAPI migration PRs for apps/meteor/app/api/server/v1 endpoints, maintainers prefer to avoid any logic changes; style-only cleanups (like removing inline comments) may be deferred to follow-ups to keep scope tight.

Learnt from: ricardogarim
Repo: RocketChat/Rocket.Chat PR: 37205
File: ee/packages/federation-matrix/src/FederationMatrix.ts:296-301
Timestamp: 2025-10-28T16:53:42.761Z
Learning: In the Rocket.Chat federation-matrix integration (ee/packages/federation-matrix/), the createRoom method from rocket.chat/federation-sdk will support a 4-argument signature (userId, roomName, visibility, displayName) in newer versions. Code using this 4-argument call is forward-compatible with planned library updates and should not be flagged as an error.

Learnt from: smirk-dev
Repo: RocketChat/Rocket.Chat PR: 39625
File: apps/meteor/app/api/server/v1/push.ts:85-97
Timestamp: 2026-03-14T14:58:58.834Z
Learning: In RocketChat/Rocket.Chat, the `push.token` POST/DELETE endpoints in `apps/meteor/app/api/server/v1/push.ts` were already migrated to the chained router API pattern on `develop` prior to PR `#39625`. `cleanTokenResult` (which strips `authToken` and returns `PushTokenResult`) and `isPushTokenPOSTProps`/`isPushTokenDELETEProps` validators already exist on `develop`. PR `#39625` only migrates `push.get` and `push.info` to the chained pattern. Do not flag `cleanTokenResult` or `PushTokenResult` as newly introduced behavior-breaking changes when reviewing this PR.

Learnt from: ricardogarim
Repo: RocketChat/Rocket.Chat PR: 37377
File: apps/meteor/ee/server/hooks/federation/index.ts:86-88
Timestamp: 2025-11-04T16:49:19.107Z
Learning: In Rocket.Chat's federation system (apps/meteor/ee/server/hooks/federation/), permission checks follow two distinct patterns: (1) User-initiated federation actions (creating rooms, adding users to federated rooms, joining from invites) should throw MeteorError to inform users they lack 'access-federation' permission. (2) Remote server-initiated federation events should silently skip/ignore when users lack permission. The beforeAddUserToRoom hook only executes for local user-initiated actions, so throwing an error there is correct. Remote federation events are handled separately by the federation Matrix package with silent skipping logic.

Learnt from: juliajforesti
Repo: RocketChat/Rocket.Chat PR: 39545
File: apps/meteor/client/views/room/body/hooks/useHasNewMessages.ts:59-61
Timestamp: 2026-03-11T22:04:20.529Z
Learning: In `apps/meteor/client/views/room/body/hooks/useHasNewMessages.ts`, the `msg.u._id === uid` early-return in the `streamNewMessage` handler is intentional: the "New messages" indicator is designed to notify about messages from other users only. Self-sent messages — including those sent from a different session/device — are always skipped, by design. Do not flag this as a multi-session regression.

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.

Learnt from: Harxhit
Repo: RocketChat/Rocket.Chat PR: 39476
File: apps/meteor/server/methods/addAllUserToRoom.ts:0-0
Timestamp: 2026-03-09T18:39:21.178Z
Learning: In apps/meteor/server/methods/addAllUserToRoom.ts, the implementation uses a single cursor pass (Users.find(userFilter).batchSize(100)) that collects both the full user objects (collectedUsers: IUser[]) and their usernames (usernames: string[]) in one iteration. `beforeAddUserToRoom` is then called once with the full usernames batch (preserving batch-validation semantics), and the subsequent subscription/message processing loop iterates over the same stable `collectedUsers` array — no second DB query is made. This avoids any race condition between validation and processing while preserving the original batch-validation behavior.

Learnt from: Dnouv
Repo: RocketChat/Rocket.Chat PR: 37057
File: packages/apps-engine/src/definition/accessors/IUserRead.ts:23-27
Timestamp: 2025-09-25T09:59:26.461Z
Learning: AppUserBridge.getUserRoomIds in apps/meteor/app/apps/server/bridges/users.ts always returns an array of strings by mapping subscription documents to room IDs, never undefined, even when user has no room subscriptions.

Learnt from: Dnouv
Repo: RocketChat/Rocket.Chat PR: 37057
File: packages/apps-engine/src/definition/accessors/IUserRead.ts:23-27
Timestamp: 2025-09-25T09:59:26.461Z
Learning: AppUserBridge.getUserRoomIds in apps/meteor/app/apps/server/bridges/users.ts always returns an array of strings (mapping subscription documents to room IDs), never undefined, even when user has no room subscriptions.

Learnt from: tassoevan
Repo: RocketChat/Rocket.Chat PR: 38528
File: apps/meteor/client/startup/roles.ts:14-14
Timestamp: 2026-02-10T16:32:49.806Z
Learning: In Rocket.Chat's Meteor client code, DDP streams use EJSON which automatically deserializes Date objects. Stream handlers (e.g., sdk.stream()) receive Date fields as Date objects directly and do not require manual conversion using `new Date()`. Only REST API responses require manual date conversion because they return plain JSON where dates are serialized as strings.

Learnt from: ahmed-n-abdeltwab
Repo: RocketChat/Rocket.Chat PR: 38913
File: packages/ddp-client/src/legacy/types/SDKLegacy.ts:34-34
Timestamp: 2026-02-25T20:10:16.987Z
Learning: In the RocketChat/Rocket.Chat monorepo, packages/ddp-client and apps/meteor do not use TypeScript project references. Module augmentations in apps/meteor (e.g., declare module 'rocket.chat/rest-typings') are not visible when compiling packages/ddp-client in isolation, which is why legacy SDK methods that depend on OperationResult types for OpenAPI-migrated endpoints must remain commented out.

Learnt from: MartinSchoeler
Repo: RocketChat/Rocket.Chat PR: 37557
File: apps/meteor/client/views/admin/ABAC/AdminABACRooms.tsx:115-116
Timestamp: 2025-11-27T17:56:26.050Z
Learning: In Rocket.Chat, the GET /v1/abac/rooms endpoint (implemented in ee/packages/abac/src/index.ts) only returns rooms where abacAttributes exists and is not an empty array (query: { abacAttributes: { $exists: true, $ne: [] } }). Therefore, in components consuming this endpoint (like AdminABACRooms.tsx), room.abacAttributes is guaranteed to be defined for all returned rooms, and optional chaining before calling array methods like .join() is sufficient without additional null coalescing.

Learnt from: dougfabris
Repo: RocketChat/Rocket.Chat PR: 39892
File: apps/meteor/client/views/room/contextualBar/Threads/Thread.tsx:150-155
Timestamp: 2026-03-27T14:52:56.865Z
Learning: In Rocket.Chat, there are two different `ModalBackdrop` components with different prop APIs. During review, confirm the import source: (1) `rocket.chat/fuselage` `ModalBackdrop` uses `ModalBackdropProps` based on `BoxProps` (so it supports `onClick` and other Box/DOM props) and does not have an `onDismiss` prop; (2) `rocket.chat/ui-client` `ModalBackdrop` uses a narrower props interface like `{ children?: ReactNode; onDismiss?: () => void }` and handles Escape keypress and outside mouse-up, and it does not forward arbitrary DOM props such as `onClick`. Flag mismatched props (e.g., `onDismiss` passed to the fuselage component or `onClick` passed to the ui-client component) and ensure the usage matches the correct component being imported.