fix(replay): stop mid-load unmounts breaking embedded recordings lists by mp-hog · Pull Request #81597 · PostHog/posthog

mp-hog · 2026-08-11T23:19:36Z

Problem

Leaving an embedded recordings list while it is still loading throws a KEA store error, and later visits can find the list stuck on "Loading recordings…". The experiment Recordings tab hits this hardest: users open the tab, click away mid-load, and it comes back blank.

loadSessionRecordings reads values.filters after await api.recordings.list(...) resumes, to report fetch analytics.
Reading values on an unmounted keyed logic throws [KEA] Can not find path "…" in the store, which kea-loaders turns into a spurious loadSessionRecordingsFailure.
The listener's breakpoint() — the bail-out kea arms on unmount — sits below that read, so it never gets to stop the listener.

Error tracking shows keyed variants of this daily, rising since the experiment-recordings-tab rollout put more embedded lists in front of users: experiment tabs and bare keys, vision scanner runs.

Complements #78247, which guards component-side bare reads of this logic. This PR guards the loader's own async resume.

Changes

loadSessionRecordings captures values.filters once, before any await, and reports fetch analytics from the captured value. Actions are safe to dispatch after unmount; only values reads throw.
The existing breakpoint() stays after the report, still guarding the post-await values reads in the return value.
Alternative rejected: moving breakpoint() above the report. That drops superseded and abandoned fetches — the slow tail — from replay_list_load_ms, skewing the latency histogram toward fast responses.
Side fix: a superseded load used to report the new filters with the old request's timing. It now reports the filters the request was built from.

How did you test this code?

Added two jest regression tests, each verified to fail against the pre-branch code:
- Unmount mid-flight: holds api.recordings.list on a controlled promise, unmounts, resolves. Fails before (KEA store error → failure action); passes now.
- Supersede mid-flight: changes filters while a load is in flight, then resolves the stale response. Locks in that the fetch report still fires with request-time filters; also fails if breakpoint() moves above the report.
pnpm --filter=@posthog/frontend fix — clean.
Local typescript:check reports only pre-existing errors from the unbuilt local @posthog/quill workspace, none in changed files; CI is the authority.
Not done: no manual browser reproduction of the race.

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Docs update

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🤖 Agent context

Autonomy: Human-driven (agent-assisted)

Takes over the original breakpoint-move fix on this branch after review flagged its side effect — superseded fetches vanishing from analytics — as avoidable.
Verified against kea 4 pre-release source: beforeUnmount bumps every listener breakpoint counter, kea-loaders swallows breakpoint throws, and built-logic action dispatches have no mount check.
Cross-checked in-repo precedents: databaseTableListLogic (isMounted() guards), dataNodeLogic (AbortController + breakpoints).
Tools: Claude Code (Fable 5) via PostHog Desktop. Skills: /writing-tests, /writing-code-comments, /writing-pr-descriptions.

Created with PostHog Desktop

loadSessionRecordings read values.filters after the API await resumed but before its breakpoint() guard, so embedded playlists (experiment recordings tab, vision scanner runs) that unmounted mid-request threw "[KEA] Can not find path" and dispatched a spurious failure. Move the breakpoint above the values reads; kea bumps breakpoint counters on beforeUnmount, so the resumed listener now aborts silently. Generated-By: PostHog Desktop Task-Id: 03c64c82-7dfc-4d5f-8fed-3d5de52245f5

trunk-io · 2026-08-11T23:19:39Z

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github-actions · 2026-08-11T23:24:15Z

🤖 CI report

✅ Bundle size — 🟢 -2.1 KiB (-0.0%)

Uncompressed size of every built .js bundle, compared against the base branch.

Total: 67.75 MiB · 🟢 -2.1 KiB (-0.0%)

File	Size	Δ vs base
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`exporter/src/exporter/scenes/ExporterNotebookScene.js`	3.31 MiB	🔺 +243.4 KiB (+7.7%)
`posthog-app/_parent/products/workflows/frontend/Workflows/WorkflowScene.js`	91.9 KiB	🟢 -102.5 KiB (-52.7%)
`exporter/_parent/products/workflows/frontend/Workflows/Workflow.js`	95.1 KiB	🔺 +95.1 KiB (new)
`posthog-app/_parent/products/error_tracking/frontend/scenes/ErrorTrackingIssueScene/ErrorTrackingIssueScene.js`	54.3 KiB	🟢 -48.9 KiB (-47.4%)
`posthog-app/_parent/products/actions/frontend/pages/Action.js`	9.2 KiB	🟢 -22.2 KiB (-70.7%)
`posthog-app/src/scenes/authentication/signup/Signup.js`	19.8 KiB	🔺 +19.8 KiB (new)
`posthog-app/_parent/products/signals/frontend/inbox/InboxScene.js`	721.0 KiB	🔺 +18.1 KiB (+2.6%)
`render-query/src/render-query/render-query.js`	21.74 MiB	🔺 +16.9 KiB (+0.1%)
`posthog-app/src/scenes/authentication/invite-signup/InviteSignup.js`	16.3 KiB	🔺 +14.6 KiB (+825.9%)
`posthog-app/src/scenes/authentication/login/Login.js`	9.4 KiB	🔺 +7.5 KiB (+405.6%)
`posthog-app/src/scenes/authentication/verify-email/VerifyEmail.js`	6.4 KiB	🔺 +4.6 KiB (+261.5%)
`posthog-app/_parent/products/workflows/frontend/Workflows/Workflow.js`	4.3 KiB	🔺 +4.3 KiB (new)
`exporter/_parent/products/customer_analytics/frontend/components/AccountRelationshipsInput/CyclotronJobInputAccountRelationships.js`	3.6 KiB	🔺 +3.6 KiB (new)
`exporter/_parent/products/customer_analytics/frontend/components/AccountPropertiesInput/CyclotronJobInputAccountProperties.js`	3.3 KiB	🔺 +3.3 KiB (new)
`posthog-app/_parent/products/logs/frontend/scenes/LogsAlertDetailScene/LogsAlertDetailScene.js`	29.5 KiB	🔺 +3.3 KiB (+12.4%)
`exporter/_parent/products/alerts/frontend/views/EditAlertModal.js`	114.6 KiB	🟢 -3.1 KiB (-2.6%)
`posthog-app/_parent/products/logs/frontend/LogsScene.js`	37.6 KiB	🔺 +2.8 KiB (+8.0%)
`exporter/_parent/products/conversations/frontend/components/SlaBusinessHours/CyclotronJobInputBusinessHours.js`	2.7 KiB	🔺 +2.7 KiB (new)
`posthog-app/src/scenes/authentication/signup/SignupContainer.js`	removed	🟢 -1.8 KiB (-100.0%)
`exporter/src/exporter/exporter.js`	17.4 KiB	🟢 -1.7 KiB (-9.0%)
`posthog-app/src/scenes/notebooks/NotebookCanvasScene.js`	16.9 KiB	🔺 +1.6 KiB (+10.2%)
`posthog-app/src/scenes/notebooks/NotebookPanel/NotebookPanel.js`	18.6 KiB	🔺 +1.6 KiB (+9.2%)
`posthog-app/src/scenes/notebooks/NotebookScene.js`	24.5 KiB	🔺 +1.6 KiB (+6.8%)
`posthog-app/src/scenes/persons/PersonScene.js`	36.9 KiB	🔺 +1.4 KiB (+3.9%)
`exporter/_parent/products/conversations/frontend/components/Assignee/CyclotronJobInputAssignee.js`	1.3 KiB	🔺 +1.3 KiB (new)
`exporter/_parent/products/conversations/frontend/components/TicketTags/CyclotronJobInputTicketTags.js`	1.1 KiB	🔺 +1.1 KiB (new)

_{Posted automatically by build-bundle-size-report · uncompressed bytes from dist-report}

✅ Eager graph — within budget

How much code each root ships on the eager path — downloaded and parsed before the surface is interactive. Measured from the esbuild output chunks (post-tree-shake, static imports only); lazy import() / React.lazy chunks are not counted.

Root	Eager (shipped)	Δ vs base	Budget
entry (logged-out pages, app bootstrap) `src/index.tsx`	1.27 MiB · 22 files	🔺 +3.6 KiB (+0.3%)	`███░░░░░░░` 28.1% of 4.51 MiB
authenticated shell (every logged-in page) `src/scenes/AuthenticatedShell.tsx`	8.47 MiB · 3,134 files	🔺 +115.8 KiB (+1.4%)	`█████████░` 87.2% of 9.71 MiB

🟢 node_modules/monaco-editor/ stays out of src/index.tsx
🟢 src/lib/components/ActivityLog/describers stays out of src/index.tsx
🟢 [object Object] stays out of src/index.tsx
🟢 [object Object] stays out of src/index.tsx
🟢 node_modules/monaco-editor/ stays out of src/scenes/AuthenticatedShell.tsx
🟢 src/lib/components/ActivityLog/describers stays out of src/scenes/AuthenticatedShell.tsx
🟢 [object Object] stays out of src/scenes/AuthenticatedShell.tsx
🟢 [object Object] stays out of src/scenes/AuthenticatedShell.tsx

Largest files eagerly shipped from src/index.tsx

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126.8 KiB	`../node_modules/.pnpm/react-dom@18.3.1_react@18.3.1/node_modules/react-dom/cjs/react-dom.production.min.js`
24.6 KiB	`../node_modules/.pnpm/buffer@6.0.3/node_modules/buffer/index.js`
6.3 KiB	`../node_modules/.pnpm/react@18.3.1/node_modules/react/cjs/react.production.min.js`
4.5 KiB	`../node_modules/.pnpm/@jspm+core@2.1.0/node_modules/@jspm/core/nodelibs/browser/process.js`
3.9 KiB	`../node_modules/.pnpm/scheduler@0.23.2/node_modules/scheduler/cjs/scheduler.production.min.js`
1.4 KiB	`../node_modules/.pnpm/base64-js@1.5.1/node_modules/base64-js/index.js`
1.3 KiB	`src/RootErrorBoundary.tsx`
912 B	`../node_modules/.pnpm/ieee754@1.2.1/node_modules/ieee754/index.js`
789 B	`src/scenes/ChunkLoadErrorBoundary.tsx`
762 B	`src/index.tsx`

Largest files eagerly shipped from src/scenes/AuthenticatedShell.tsx

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285.3 KiB	`../node_modules/.pnpm/posthog-js@1.410.1/node_modules/posthog-js/dist/rrweb.js`
267.7 KiB	`../node_modules/.pnpm/@posthog+icons@0.38.0_react-dom@18.3.1_react@18.3.1__react@18.3.1/node_modules/@posthog/icons/dist/posthog-icons.es.js`
238.4 KiB	`src/taxonomy/core-filter-definitions-by-group.json`
231.5 KiB	`../node_modules/.pnpm/posthog-js@1.410.1/node_modules/posthog-js/dist/module.js`
154.3 KiB	`../node_modules/.pnpm/re2js@0.4.1/node_modules/re2js/build/index.esm.js`
126.8 KiB	`../node_modules/.pnpm/react-dom@18.3.1_react@18.3.1/node_modules/react-dom/cjs/react-dom.production.min.js`
105.2 KiB	`src/lib/api.ts`
94.6 KiB	`../packages/quill/packages/quill/dist/index.js`
93.3 KiB	`../node_modules/.pnpm/prosemirror-view@1.40.1/node_modules/prosemirror-view/dist/index.js`
90.6 KiB	`../node_modules/.pnpm/@tiptap+core@3.20.6_@tiptap+pm@3.20.6/node_modules/@tiptap/core/dist/index.js`

_{Posted automatically by check-eager-graph · sizes are eager output bytes (shipped, post-tree-shake) from the esbuild metafile · part of #32479}

✅ Toolbar bundle — eager 2.20 MiB within budget

What the toolbar ships to customer pages, measured from the esbuild output (minified, post-tree-shake). The eager set is the entry plus everything statically imported from it — fetched before any feature runs; deferred chunks load lazily. The eager guardrail is 5.72 MiB. Each output file must also stay below 10 MB, where CloudFront stops compressing it. The module boundary is enforced separately by check-toolbar-graph.

Metric	Size	Δ vs base	Budget
Eager (shipped) entry + static imports	2.20 MiB · 17 files	🔺 +3.8 KiB (+0.2%)	`████░░░░░░` 38.5% of 5.72 MiB
Deferred (lazy)	2.08 MiB · 33 files	🟢 -15 B (-0.0%)	n/a — loads on demand
Loader `dist/toolbar.js`	1.1 KiB	no change	`█░░░░░░░░░` 5.8% of 19.5 KiB

Largest eagerly-shipped chunks

Size	File
729.2 KiB	`dist/toolbar/toolbar-app-KABLUAZC.css`
553.0 KiB	`dist/toolbar/chunk-chunk-CAJJBQHG.js`
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20.9 KiB	`dist/toolbar/chunk-chunk-QGUDWYKZ.js`
12.2 KiB	`dist/toolbar/chunk-chunk-PIK3PADE.js`

_{Posted automatically by check-toolbar-size · sizes are toolbar output bytes (shipped, post-tree-shake) from the esbuild metafile}

✅ Dist folder size — 🔺 +7.55 MiB (+0.5%)

Total size of the built frontend/dist folder (all assets), compared against the base branch.

Total: 1429.02 MiB · 🔺 +7.55 MiB (+0.5%)

The `as ReturnType<typeof api.recordings.list>` cast contextually typed the Promise constructor, so its resolve callback no longer matched the `(value: unknown) => void` holder under strict function types (TS2322, caught by CI's Frontend typechecking). Build the promise untyped and cast only at the mock's return position. Generated-By: PostHog Desktop Task-Id: 03c64c82-7dfc-4d5f-8fed-3d5de52245f5

trunk-io · 2026-08-12T01:02:15Z

_{View Full Report ↗︎ ⋅ Docs}

Capture values.filters before the awaits and report the fetch from the captured value, restoring breakpoint() to after the report. Superseded and abandoned fetches keep counting toward the list load-time metrics (no survivorship bias toward fast responses), and the report now carries the filters the request was built from rather than whatever they are when the response lands. Unmount safety is unchanged: the only post-await `values` reads sit behind the breakpoint, and dispatching an action on an unmounted logic is safe — only `values` reads throw. Adds a regression test that fails both if the report goes back to reading live values and if breakpoint() moves back above the report. Generated-By: PostHog Desktop Task-Id: 139ec0b8-42da-4ec0-b68d-d0a0e238992e

github-actions · 2026-08-12T20:33:36Z

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greptile-apps · 2026-08-12T20:35:58Z

_{Reviews (1): Last reviewed commit: "fix(replay): keep fetch reporting for su..." | Re-trigger Greptile}

pr-assigner-resolver-posthog Bot assigned mp-hog Aug 11, 2026

mp-hog added the run-ci-frontend Force ci-storybook's full visual-regression matrix to run even on a draft PR label Aug 12, 2026 — with PostHog

mp-hog closed this Aug 12, 2026

mp-hog reopened this Aug 12, 2026

mp-hog changed the title ~~fix(replay): abort in-flight list load when playlist logic unmounts~~ fix(replay): stop mid-load unmounts breaking embedded recordings lists Aug 12, 2026

mp-hog marked this pull request as ready for review August 12, 2026 20:33

github-actions Bot deployed to preview-pr-81597 August 12, 2026 20:33 View deployment

pr-assigner-resolver-posthog Bot requested review from a team, TueHaulund, arnohillen, fasyy612 and ksvat and removed request for a team August 12, 2026 20:33

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fix(replay): stop mid-load unmounts breaking embedded recordings lists - #81597

fix(replay): stop mid-load unmounts breaking embedded recordings lists#81597
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