fix: message list not scrolling to bottom when sending a message - #41770
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fix: message list not scrolling to bottom when sending a message#41770ndo84bw wants to merge 2 commits into
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The list only scrolls to your own message once `streamNewMessage` runs, and that callback is skipped whenever the `sendMessage` response is processed before the server echo: `temp` has been cleared by then, so the echo looks like a message the client has already seen. Nothing scrolls, and nothing catches it up afterwards. Trigger the scroll from the locally appended optimistic message instead, the same way RocketChat#40956 already does for the thread panel. The list no longer waits for a round-trip to follow a message the client added itself. Also mark the list as at-bottom before `scrollToIndex` runs, so the ResizeObserver in `useKeepAtBottom` still corrects the position if content grows before Virtua's rAF. Unlike `ThreadMessageList` this component has no early return when the virtualizer handle is missing, so the flag is only set when there is one. The spec shared a single `isAtBottom` ref across all tests without resetting it, which let at-bottom state leak from one test into the next once the component started writing to that ref. Reset it in `beforeEach`. Refs RocketChat#41746 Assisted-by: claude-code:claude-opus-5
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🦋 Changeset detectedLatest commit: 0770268 The changes in this PR will be included in the next version bump. This PR includes changesets to release 3 packages
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Walkthrough
ChangesMessage scroll fix
Estimated code review effort: 2 (Simple) | ~10 minutes Mergeability Score: ⚪ Minimal · up to This localized change makes the message list scroll when the sender’s own message appears, addressing the timing-dependent failure without introducing an actionable merge-blocking risk; it is merge-ready after normal checks and review. Suggested labels: Suggested reviewers: 🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
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Inline comments:
In `@apps/meteor/client/views/room/MessageList/MessageList.spec.tsx`:
- Around line 211-215: Add temp: true to the otherUserMessage fixture in the
relevant MessageList test so lastMessage.temp is true while the message remains
authored by another user, covering the intended no-jump behavior.
In `@apps/meteor/client/views/room/MessageList/MessageList.tsx`:
- Around line 184-185: Remove the newly added implementation comments around the
own temporary-message append and the related scroll-to-bottom logic in
MessageList, including both referenced comment blocks, while leaving the
surrounding behavior unchanged.
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📒 Files selected for processing (3)
.changeset/lucky-boxes-shave.mdapps/meteor/client/views/room/MessageList/MessageList.spec.tsxapps/meteor/client/views/room/MessageList/MessageList.tsx
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**/*.{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/client/views/room/MessageList/MessageList.spec.tsxapps/meteor/client/views/room/MessageList/MessageList.tsx
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Files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsxapps/meteor/client/views/room/MessageList/MessageList.tsx
🧠 Learnings (20)
📓 Common learnings
Learnt from: gabriellsh
Repo: RocketChat/Rocket.Chat PR: 40755
File: apps/meteor/client/views/room/MessageList/MessageList.tsx:84-94
Timestamp: 2026-06-02T13:27:22.143Z
Learning: In `apps/meteor/client/views/room/MessageList/MessageList.tsx`, the keep-at-bottom `useEffect` intentionally calls `virtualizerRef.current.scrollToIndex(messagesLength, { align: 'end' })` where `messagesLength` is one past the last rendered item index. Using `messagesLength - 1` was tested and caused incorrect scroll positioning. The out-of-bounds index is clamped by Virtua to `itemCount - 1` (last item) — this is intentional and relies on documented stable behavior of the Virtua library. Do not flag this as a bug.
📚 Learning: 2026-02-24T19:09:09.561Z
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.
Applied to files:
.changeset/lucky-boxes-shave.md
📚 Learning: 2026-05-06T20:48:08.244Z
Learnt from: d-gubert
Repo: RocketChat/Rocket.Chat PR: 40186
File: apps/meteor/app/apps/server/bridges/uiInteraction.ts:2-2
Timestamp: 2026-05-06T20:48:08.244Z
Learning: In the RocketChat/Rocket.Chat repository, Meteor's bundler does not respect the `exports` keyword in `package.json` files. Deep imports (e.g., `rocket.chat/apps/dist/server/bridges/UiInteractionBridge`) must be used instead of relying on `exports` subpath mappings. Do not suggest adding `exports` map entries to packages consumed by Meteor (e.g., `packages/apps/package.json`) as a fix for deep imports.
Applied to files:
.changeset/lucky-boxes-shave.md
📚 Learning: 2026-02-24T19:36:55.089Z
Learnt from: juliajforesti
Repo: RocketChat/Rocket.Chat PR: 38493
File: apps/meteor/tests/e2e/page-objects/fragments/home-content.ts:60-82
Timestamp: 2026-02-24T19:36:55.089Z
Learning: In RocketChat/Rocket.Chat e2e tests (apps/meteor/tests/e2e/page-objects/fragments/home-content.ts), thread message preview listitems do not have aria-roledescription="message", so lastThreadMessagePreview locator cannot be scoped to messageListItems (which filters for aria-roledescription="message"). It should remain scoped to page.getByRole('listitem') or mainMessageList.getByRole('listitem').
Applied to files:
.changeset/lucky-boxes-shave.mdapps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-02-24T19:05:56.710Z
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.
Applied to files:
.changeset/lucky-boxes-shave.md
📚 Learning: 2026-03-11T22:04:20.529Z
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.
Applied to files:
.changeset/lucky-boxes-shave.mdapps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2025-11-19T18:20:07.720Z
Learnt from: gabriellsh
Repo: RocketChat/Rocket.Chat PR: 37419
File: packages/i18n/src/locales/en.i18n.json:918-921
Timestamp: 2025-11-19T18:20:07.720Z
Learning: Repo: RocketChat/Rocket.Chat — i18n/formatting
Learning: This repository uses a custom message formatting parser in UI blocks/messages; do not assume standard Markdown rules. For keys like Call_ended_bold, Call_not_answered_bold, Call_failed_bold, and Call_transferred_bold in packages/i18n/src/locales/en.i18n.json, retain the existing single-asterisk emphasis unless maintainers request otherwise.
Applied to files:
.changeset/lucky-boxes-shave.md
📚 Learning: 2026-06-02T13:27:22.143Z
Learnt from: gabriellsh
Repo: RocketChat/Rocket.Chat PR: 40755
File: apps/meteor/client/views/room/MessageList/MessageList.tsx:84-94
Timestamp: 2026-06-02T13:27:22.143Z
Learning: In `apps/meteor/client/views/room/MessageList/MessageList.tsx`, the keep-at-bottom `useEffect` intentionally calls `virtualizerRef.current.scrollToIndex(messagesLength, { align: 'end' })` where `messagesLength` is one past the last rendered item index. Using `messagesLength - 1` was tested and caused incorrect scroll positioning. The out-of-bounds index is clamped by Virtua to `itemCount - 1` (last item) — this is intentional and relies on documented stable behavior of the Virtua library. Do not flag this as a bug.
Applied to files:
.changeset/lucky-boxes-shave.mdapps/meteor/client/views/room/MessageList/MessageList.spec.tsxapps/meteor/client/views/room/MessageList/MessageList.tsx
📚 Learning: 2026-08-05T22:03:04.374Z
Learnt from: ricardogarim
Repo: RocketChat/Rocket.Chat PR: 41707
File: apps/meteor/server/hooks/messages/processThreads.ts:66-68
Timestamp: 2026-08-05T22:03:04.374Z
Learning: In Rocket.Chat Meteor server code, `callbacks.runAsync` returns the input item rather than the asynchronous callback promise. Callers of `afterReadMessages`, including `apps/meteor/server/hooks/messages/processThreads.ts`, must invoke `callbacks.runAsync` without awaiting it so read-receipt I/O stays off the message-send path.
Applied to files:
.changeset/lucky-boxes-shave.md
📚 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/lucky-boxes-shave.md
📚 Learning: 2026-04-28T14:08:46.920Z
Learnt from: MartinSchoeler
Repo: RocketChat/Rocket.Chat PR: 40105
File: apps/meteor/client/views/room/MessageList/hooks/useTryToJumpToMessage.ts:54-67
Timestamp: 2026-04-28T14:08:46.920Z
Learning: In `apps/meteor/client/views/room/MessageList/hooks/useTryToJumpToMessage.ts`, setting `isJumpingToMessage.current = true` before the guard clauses (RoomHistoryManager.isLoading check, message not found check) is intentional. The flag means "a jump is pending/in progress" and must stay `true` through all intermediate early-return paths (loading, unresolved message, etc.) so that downstream scroll and load behavior is suppressed while waiting for the jump conditions to be satisfied. Do not flag this as a "flag stuck true" bug.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-05-26T19:18:05.882Z
Learnt from: MartinSchoeler
Repo: RocketChat/Rocket.Chat PR: 40644
File: apps/meteor/client/views/room/contextualBar/Threads/components/ThreadMessageList.tsx:145-147
Timestamp: 2026-05-26T19:18:05.882Z
Learning: In `apps/meteor/client/views/room/contextualBar/Threads/components/ThreadMessageList.tsx`, the `clearMsgJumpParam` cleanup in the timed effect (around line 145) intentionally clears the `msg` query parameter only when the target message IS found in `messages` (thread replies) and is not `mainMessage._id`. This is correct behavior: if `msgJumpParam` refers to a non-reply message (e.g., a main channel message), the main message list handles cleanup, so `ThreadMessageList` must not clear the param in that case.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-04-17T18:33:27.211Z
Learnt from: d-gubert
Repo: RocketChat/Rocket.Chat PR: 39858
File: apps/meteor/tests/e2e/apps/uikit-interactions.spec.ts:123-151
Timestamp: 2026-04-17T18:33:27.211Z
Learning: In RocketChat/Rocket.Chat (`apps/meteor/tests/e2e/apps/uikit-interactions.spec.ts`), `executeBlockActionHandler` invocations originating from a **modal** surface intentionally do NOT include a `block_action_room` (room property) in the interaction payload. Modals are not scoped to a room, so no room id is available in that context. Do not flag the absence of a room assertion in the modal block-action test as a missing coverage bug; instead, document it explicitly with a `test.step` asserting the room entry is `undefined`.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-04-29T20:06:34.862Z
Learnt from: tassoevan
Repo: RocketChat/Rocket.Chat PR: 40268
File: apps/meteor/client/startup/incomingMessages.ts:21-25
Timestamp: 2026-04-29T20:06:34.862Z
Learning: In `apps/meteor/client/startup/incomingMessages.ts`, the `Messages.state.update` predicate that strips `ignored` from records when `'ignored' in sub` is false (i.e., the subscription update has no `ignored` field) is intentional. Absence of `ignored` in a `subscriptions-changed` event means the user's ignore list is empty/reset, so clearing all existing `ignored` flags on messages for that room is the correct behavior. Do not flag this as an unintentional ignored-state reset on unrelated subscription updates.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-07-30T23:35:00.754Z
Learnt from: nazabucciarelli
Repo: RocketChat/Rocket.Chat PR: 41631
File: apps/meteor/client/views/room/modals/ReportMessageModal/ReportMessageModal.tsx:45-46
Timestamp: 2026-07-30T23:35:00.754Z
Learning: In `apps/meteor/client/views/room/modals/ReportMessageModal/ReportMessageModal.tsx`, `toPlainTextRoot` is intentionally used only when `message.msg` exceeds `getMarkdownParserLimit()`. Short messages lacking `message.md`, including E2EE messages, retain the pre-existing `MarkdownText` inline rendering behavior; its collapsed line breaks are outside the scope of the parser-limit fallback work.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-07-07T19:21:28.123Z
Learnt from: juliajforesti
Repo: RocketChat/Rocket.Chat PR: 41122
File: apps/meteor/client/views/room/contextualBar/RoomMembers/useMembersListNavigation.ts:16-34
Timestamp: 2026-07-07T19:21:28.123Z
Learning: In apps/meteor/client/views/room/contextualBar/RoomMembers/useMembersListNavigation.ts (and similar react-virtuoso-based keyboard navigation code in Rocket.Chat), react-virtuoso's `scrollToIndex` handles out-of-bounds index values (e.g., negative or beyond the last item) silently without throwing errors, so explicit clamping of targetIndex before calling `virtuosoRef.current?.scrollToIndex(...)` is not necessary.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2025-11-24T17:08:17.065Z
Learnt from: CR
Repo: RocketChat/Rocket.Chat PR: 0
File: .cursor/rules/playwright.mdc:0-0
Timestamp: 2025-11-24T17:08:17.065Z
Learning: Applies to apps/meteor/tests/e2e/**/*.spec.ts : Ensure clean state for each test execution in Playwright tests
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-03-06T18:10:15.268Z
Learnt from: tassoevan
Repo: RocketChat/Rocket.Chat PR: 39397
File: packages/gazzodown/src/code/CodeBlock.spec.tsx:47-68
Timestamp: 2026-03-06T18:10:15.268Z
Learning: In tests (especially those using testing-library/dom/jsdom) for Rocket.Chat components, the HTML <code> element has an implicit ARIA role of 'code'. Therefore, screen.getByRole('code') or screen.findByRole('code') will locate <code> elements even without a role attribute. Do not flag findByRole('code') as invalid in reviews; prefer using the implicit role instead of adding role="code" unless necessary for accessibility.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsx
📚 Learning: 2026-03-27T14:52:56.865Z
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.
Applied to files:
apps/meteor/client/views/room/MessageList/MessageList.spec.tsxapps/meteor/client/views/room/MessageList/MessageList.tsx
📚 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/client/views/room/MessageList/MessageList.spec.tsxapps/meteor/client/views/room/MessageList/MessageList.tsx
🔇 Additional comments (3)
apps/meteor/client/views/room/MessageList/MessageList.tsx (1)
85-86: LGTM!Also applies to: 186-193, 195-195, 198-198, 201-203, 222-222
.changeset/lucky-boxes-shave.md (1)
1-5: LGTM!apps/meteor/client/views/room/MessageList/MessageList.spec.tsx (1)
128-128: LGTM!Also applies to: 182-198
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All reported issues were addressed across 3 files
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Re-trigger cubic
Comparing message counts treated a prepend as a new send: while your own message is still pending, loading older history grew the list and pulled it back to the bottom. Track the id of the last message instead, which does not change when messages are added above it. That tracking has to happen before the early returns in the effect, otherwise it stays unset on the first render and the next run fires without anything having been sent. The negative test used a message without `temp`, so the guard short-circuited before the user check and the test could not have caught a regression there. Set `temp` on it, and add a test for the prepend case. Assisted-by: claude-code:claude-opus-5
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Pushed a follow-up commit. Prepend is treated as a new send ( While fixing it I found a second problem the review did not catch: the effect returns early during room initialisation, so the ref was never set on the first render and the next run fired without anything having been sent. The tracking now happens before those returns. Negative test did not test anything (both of you): correct. Left as is, with reasons as direct reply. |
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All reported issues were addressed across 2 files (changes from recent commits).
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Proposed changes (including videos or screenshots)
The message list often does not scroll to the bottom after you send a message.
Your message is added to the list right away and marked
temp. The scroll is triggered bystreamNewMessage, which only runs ifLegacyRoomManagerstill sees the incoming echo as new. When the response tosendMessageis processed before the echo arrives,tempis already gone, the echo counts as known, and no scroll happens. Nothing corrects it later, becausestreamNewMessageis the only trigger left.handleComposerResizelooks like a second one, butRoomBody.tsxpassesonResizedown and nothing ever calls it.So it depends on which of the two the client handles first, not on how far apart they arrive. In one run a send scrolled fine with the echo landing 327 ms after the response, in another it failed at 278 ms.
This PR scrolls when your own message shows up in the list, without waiting for anything from the server. Same approach #40956 already uses for the thread panel.
Verification
The bug is timing dependent, so simply retrying is not comparable between runs. To get a stable test I delayed the
stream-room-messagesecho in the client, which makes the response win on purpose. A rare failure becomes one you can measure.Local build, 20 sends per cell, list scrolled up before each send. Numbers are sends that never reached the bottom:
1 ms is already enough, because it pushes the echo behind the response. 8.6.1 behaves the same as develop.
The patched build scrolls on every send even though
streamNewMessagestill never runs in those cases. It also stops waiting for the network: on develop the list was at the bottom after 182 ms while the server response took 344 ms.Issue(s)
Fixes #41746
Steps to test or reproduce
In a room with enough history:
Unpatched this fails now and then, so try it 15 to 20 times. On a real deployment it happens far more often than on localhost.
To see it every time, delay the echo: intercept the DDP WebSocket before the app connects and re-dispatch any frame containing
stream-room-messagesfrom asetTimeoutinstead of the socket event. 1 ms is enough. I used a Tampermonkey script for that and can share it.Only the main message list is affected. Threads were already fixed in #40956.
Further comments
Why scroll on the local message instead of making
streamNewMessagereliable: keepingtempuntil the echo has been handled ties two independent async paths together and needs extra care around failed sends and retries. Reacting to the local message avoids the race and matches what the thread panel does.isAtBottom.currentis set beforescrollToIndexso theResizeObserverinuseKeepAtBottomcan still correct the position if content grows before Virtua runs the scroll. It is only set when a virtualizer handle exists, otherwise it would claim a scroll that never happened and break the existingshould do nothing if no previous scroll position is storedtest.align: 'center'is left alone, since #41410 is about changing it.Tests: one for your own optimistic message, one making sure someone else's message does not trigger the jump. Reverting only
MessageList.tsxmakes the first fail and leaves the rest passing.defaultProps.isAtBottomis now reset inbeforeEach, it is a shared ref and leaked state from one test into the next.Discovered issues (out of scope)
refactor:handleComposerResizeis dead code.RoomBody.tsxpassesonResizedown but nothing calls it. It looks like a second scroll trigger and cost me time while tracing this.bug:isAtBottomis still not derived reliably. The existingFIXMEstays valid, and this PR adds one more place that writes the ref directly.Summary by CodeRabbit