Files
LibreChat/e2e
Danny Avila 9618be6eb3 🌿 fix: Preserve Viewed Branch on Sibling-Tree Churn (#13732)
* 🌿 fix: Preserve Viewed Branch on Sibling-Tree Churn

Regenerating a message could snap the view to an unrelated newest branch.
MultiMessage reset siblingIdx to 0 (newest) on any messagesTree.length
change, but getRegenerateSubmissionMessages slices the flat message array
during a regenerate — the streaming handlers render a tree missing unrelated
sibling branches, then finalHandler restores the full set. That 2→1→2
child-count swing snapped unrelated forks to their newest sibling, so
regenerating the latest response on an older branch jumped to a previously
regenerated branch.

Replace the indiscriminate reset with per-fork branch memory: a 'seen' set
distinguishes a genuinely new sibling (submission/regeneration/edit here —
focus it) from one transiently dropped and restored (preserve the user's
branch). Decision extracted as the pure, unit-tested resolveSiblingSelection.

- client/src/utils/messages.ts: resolveSiblingSelection + tests
- MultiMessage: seen/selectedId refs, structural id-signature effect
- e2e: regenerate-latest-on-older-branch keeps the viewed branch (fails on
  the old reset, passes now)

* 🧪 test: Long-Thread Branch Preservation E2E

Add the user-reported scenario: in a multi-turn thread, regenerate an
earlier response (forking a root branch), switch back to the original, then
regenerate a later response on it — the original branch must stay intact.
Uses labeled prompts so each turn's unique reply is a reliable settle signal.
Verified it fails on the original MultiMessage and passes with the fix.

* 🎨 style: Fix import order in MultiMessage (react before recoil)

* 🌿 fix: Keep Unrelated Branches in Regenerate Optimistic Render

Regenerating a message used a flat `messages.slice(0, targetIndex)` for the
optimistic render, which also drops unrelated sibling branches that merely sit
later in the flat array. Mid-regenerate the thread briefly collapsed to a short
branch (visible flash) and the scroll jumped to the shrunken content and didn't
recover — the same flat-array root cause as the branch-reset bug.

Remove only the regenerated response and its descendants, keeping unrelated
branches. The thread (and scroll) stay put through the regenerate. This array
is render-only — the server regenerates from parentMessageId and createPayload
doesn't include it — so summing by subtree never affects the request.

Verified via a small-viewport scroll trace: old collapses 903->295px / 8->2
renders mid-stream; fixed stays 903px / 8 renders, scroll held at bottom.
Unit test covers the keep-unrelated-branches behavior (fails on the old slice).

* 🌿 fix: Let an Explicit Branch Selection Survive Streaming ID Churn

resolveSiblingSelection focused any unseen sibling id before checking the
committed selection. When an in-flight response's id is replaced mid-stream
(placeholder → server/run id, e.g. useStepHandler re-keys to runId) after the
user switched to a different sibling, that swap looked like a brand-new sibling
and stole focus back to the streaming branch.

Reorder: the committed selection wins while still present; only focus a fresh
sibling when the selection is gone (regenerated away, or its own placeholder id
was just replaced — that's how a regen/edit still takes focus, since the slice
removes the old response). Added unit tests for both churn directions.

* 🌿 fix: Only Focus a New Sibling When the Fork Actually Grew

The previous churn fix (selection-wins-first) was too aggressive: a genuinely
new sibling ADDED while the prior selection is still present — e.g. a follow-up
re-parented as a sibling after a generation-start failure — was no longer
focused, so its reply never rendered (broke message-tree generation-start
recovery e2e).

Gate new-sibling focus on actual growth: resolveSiblingSelection now takes
prevCount and only focuses a never-seen id when ids.length > prevCount. A
same-count placeholder→server id swap (churn) or a restored already-seen
sibling is not growth, so the committed selection still wins there. Covers
follow-up/new-branch focus, churn steal-prevention, and self-churn follow.

message-tree + chat e2e: 17 passed (incl. the recovered generation-start test).

* 🌿 refactor: Drop MultiMessage Branch-Memory in Favor of the Slice Fix

The regenerate-slice fix (keep unrelated branches in the optimistic render) is
the true root cause: with no spurious tree collapse, the original
setSiblingIdx(0)-on-length-change never misfires, so the branch-reset is fixed
without per-fork memory. The earlier MultiMessage rewrite (seen/selectedId/
prevCount + resolveSiblingSelection) was a symptom patch added before the root
cause was found, and its per-instance memory generated two edge-case findings
(placeholder→server id churn; divergence from external siblingIdx writes like
resume restore).

Revert MultiMessage to the simple upstream version and remove
resolveSiblingSelection (+ its tests). The slice fix + the existing branch e2e
(chat.spec: switch-back, regenerate-latest, long-thread) cover the behavior;
all 17 chat + message-tree branch specs pass with this version.

* 🌿 fix: Focus the Regenerated Response When Its Fork Count Is Unchanged

When a parent already has multiple sibling responses and the user switches to a
non-latest one and regenerates it, the optimistic slice drops the target but
keeps the other siblings, so the child count is unchanged. MultiMessage only
resets the (reversed) sibling index on a length change, so the stale index kept
pointing at the kept sibling and the regenerating response stayed hidden until
the server restored the dropped sibling at finalize (count bump → reset).

Explicitly focus the newest sibling (reversed index 0 = the appended response)
of the regenerated fork in createdHandler. Position-based, fires only on the
regenerate action, so it doesn't reintroduce the placeholder→server id churn or
external-write fragility that a per-render selection memory had.

E2E: new during-stream test (slow+counted reply marker) asserting the
regenerating response is visible before finalize; negatively verified
(fails without the focus call, passes with it).

* 🌿 fix: Eliminate Pre-Created Flash by Focusing at the Optimistic Render

The createdHandler focus removed the until-finalize bug, but a brief flash
remained between clicking regenerate and the `created` event: useChatFunctions
renders the optimistic placeholder first, and that render has the same
unchanged-count problem, so the kept sibling showed until createdHandler fired.

Extract the focus into a shared useFocusRegeneratedResponse hook and apply it at
the optimistic render too (useChatFunctions) and on `created`
(useEventHandlers). The placeholder is now focused from the first frame.

E2E: gated pre-created test — holds the SSE stream GET (the chat POST returns a
stream id; the stream is a separate GET) so `created` cannot arrive, leaving
only the optimistic render, then asserts the kept sibling is already gone. This
isolates the optimistic focus (createdHandler cannot mask it); negatively
verified (fails without the optimistic focus call).

* 🧪 test: Extend Store Mock for the Regenerate Focus Hook

useChatFunctions.regenerate.spec.tsx mocks ~/store and recoil partially; the new
useFocusRegeneratedResponse calls store.messagesSiblingIdxFamily via a recoil
`set`, neither of which the mock provided (TypeError on regenerate). Add
messagesSiblingIdxFamily to the store mock and `set` to the useRecoilCallback
mock. Test-only; production code unchanged.
2026-06-14 09:38:06 -04:00
..

LibreChat e2e

The mock e2e profile is the safest default for generated tests. It starts LibreChat with e2e/config/librechat.e2e.yaml, injects an in-process fake LLM (via LIBRECHAT_TEST_RUN_HOOK), creates an authenticated e2e user, and avoids real provider credentials.

Recording Tests

Use Playwright codegen when you want to turn an exploratory browser session into a draft test:

npm run e2e:record

That command builds the app, starts the LibreChat test server (with an in-process fake LLM) when needed, writes e2e/storageState.json, and opens Playwright codegen at /c/new. The npm script uses http://localhost:3333 so it does not collide with a normal dev server on 3080. Raw recordings are written to e2e/recordings/ and ignored by git.

For a real local LibreChat config instead of the mock profile:

npm run e2e:record:local

Useful direct options:

node e2e/setup/record.js --url=http://localhost:3080/c/new
node e2e/setup/record.js --profile=local --no-output
node e2e/setup/record.js --auth-only
node e2e/setup/record.js --output=e2e/recordings/settings-draft.spec.ts

LLM-Assisted Loop

  1. Start npm run e2e:record.
  2. Let the LLM use Computer Use to operate the headed Playwright browser.
  3. Stop codegen after the workflow is captured.
  4. Move the useful parts from e2e/recordings/ into a committed spec under e2e/specs/mock/.
  5. Replace brittle generated selectors with role, label, text, or data-testid locators.
  6. Add assertions that prove the behavior, not just the clicked path.
  7. Run the finished spec with npm run e2e:mock -- <spec name>.

Generated recordings are a draft, not the final test. The committed version should use the shared helpers in e2e/specs/mock/helpers.ts where possible, wait on network or visible UI state instead of fixed sleeps, and keep test data deterministic.