fix(mobile): recover from screen render errors

[juliusmarminge]

A render error in a mobile route, thread feed, or split-view pane currently ends the session. This adds small boundaries at those render seams so the user can retry immediately, copy the error details, and leave a failed route. A feed failure keeps its header and composer visible.

This replaces the larger approach in #13145. It uses the native stack's screenLayout, a feed boundary, and boundaries around the split-view sidebar and inspector. It does not add a second error log or Diagnostics UI. Errors above navigation still follow Expo's existing fatal recovery path.

Device proof

A temporary, uncommitted render throw was inserted at the same feed call site on the base and this branch. Both devices used the same seeded environment and thread. The development error overlay was dismissed on the branch to show the in-session fallback.

Before · iOS feed render error

After · iOS feed recovers in place, with header and composer visible

A forced Home render error also kept a way into Settings on iOS and Android:

Verification

• iPhone 16 Pro simulator (iOS 18.6) and Pixel 10 Pro emulator (Android 17): forced feed and Home render errors reached their fallbacks; Open settings reached Settings on both. On Android, removing the feed fault and tapping Try again restored the conversation in place.
• The recovery fallback scrolls so its actions remain reachable with larger accessibility text; the updated iOS Home capture above uses the scrollable fallback.
• apps/mobile: pnpm exec tsc --noEmit passed. Targeted lint passed with only existing warnings in the large touched components; RenderErrorBoundary.tsx has none.
• React Doctor reported complexity warnings in the existing large AdaptiveWorkspaceLayout, ThreadDetailScreen, and ThreadRouteScreen components.
• The app has no runnable React Native component renderer in its node test harness, so the boundary is checked on devices instead of by static-markup tests. The persistent split inspector was reviewed by code; the iPad mini used for an additional pass selected its compact Files route, so that layout was not device-verified.

Model: GPT-6 Astra (Codex). Design consensus and review: Claude Opus 5.5 (T3 delegated agent).

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Summary by CodeRabbit

• Bug Fixes
  • Added recovery screens for rendering failures across mobile screens, conversations, workspace sidebars, and inspectors.
  • Where available, recovery screens let you retry, copy error details, or leave the affected view. Navigation options vary by screen.
  • Failures reset when the relevant route or conversation context changes.

[github-actions]

Thread transfer impact

✅ Thread transfer remains within every enforced ceiling.

Provider	Metric	Main baseline	This PR	Impact	PR ceiling
Codex	Total thread wire	13.5 KiB	13.5 KiB	−15 B (−0.1%)	15.1 KiB	✅
Codex	Thread snapshot wire	7.1 KiB	7.1 KiB	0 B (0.0%)	7.3 KiB	✅
Codex	Live turn WebSocket wire	6.5 KiB	6.5 KiB	−15 B (−0.2%)	7.8 KiB	✅
Codex	Live turn WebSocket decoded	56.3 KiB	56.3 KiB	0 B (0.0%)	66.4 KiB	✅
Codex	Live turn messages	10	10	0 (0.0%)	21	✅
Claude	Total thread wire	13.5 KiB	13.5 KiB	−3 B (−0.0%)	15.1 KiB	✅
Claude	Thread snapshot wire	7.1 KiB	7.1 KiB	+1 B (+0.0%)	7.3 KiB	✅
Claude	Live turn WebSocket wire	6.4 KiB	6.4 KiB	−4 B (−0.1%)	7.8 KiB	✅
Claude	Live turn WebSocket decoded	57.0 KiB	57.0 KiB	0 B (0.0%)	66.4 KiB	✅
Claude	Live turn messages	9	9	0 (0.0%)	21	✅

Baseline: db898a3 · PR result: 05a542e · Source CI: success

Scenario and decoded snapshot size

10 historical turns, 5 command tools per turn, 878.9 KiB retained MCP result per historical turn, and a 1.05 MiB retained result in the measured turn.

• Codex decoded thread snapshot: 114.0 KiB
• Claude decoded thread snapshot: 114.6 KiB

Updated in place by a trusted workflow. PR artifacts are strictly validated and never executed.

[macroscopeapp]

Approvability

Verdict: Not approved

Macroscope's review found this PR not approvable — Adds a new render-error recovery UI and applies it across the mobile navigation stack, conversation feed, sidebar, and inspector panes. Because this changes failure behavior across multiple existing production paths and introduces new user-facing actions, the scope merits human validation.

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ℹ️ Recent review info

⚙️ Run configuration

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Plan: Team

Run ID: 37c8241c-4d9c-438e-a5d0-75f7bd89bc00

📥 Commits

Reviewing files that changed from the base of the PR and between db898a3 and 05a542e.

📒 Files selected for processing (7)

• apps/mobile/src/Stack.tsx
• apps/mobile/src/components/RenderErrorBoundary.tsx
• apps/mobile/src/features/layout/AdaptiveWorkspaceLayout.tsx
• apps/mobile/src/features/layout/workspace-inspector-pane.tsx
• apps/mobile/src/features/threads/ThreadDetailScreen.tsx
• apps/mobile/src/features/threads/ThreadRouteScreen.tsx
• apps/mobile/src/features/threads/thread-inspector-content-stack.tsx

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📝 Walkthrough

Walkthrough

Mobile screens, workspace areas, and thread content now use render error boundaries. Failures display a shared fallback view with error details and retry controls. Route, pathname, thread, and working-directory values reset boundaries where configured.

Changes

Mobile render error handling

Layer / File(s)	Summary
Shared boundary and fallback apps/mobile/src/components/RenderErrorBoundary.tsx	Adds error capture, reset-key and retry handling, error-detail formatting, and a fallback view with retry, copy-details, and optional exit actions.
Navigator screen guard apps/mobile/src/Stack.tsx	Wraps root screens and new-task flow content in a boundary. The fallback provides route-aware exit actions, and the boundary resets when route params change.
Workspace sidebar and inspector guards apps/mobile/src/features/layout/AdaptiveWorkspaceLayout.tsx, apps/mobile/src/features/layout/workspace-inspector-pane.tsx	Adds render boundaries for the sidebar and inspector. The inspector receives the pathname and resets its boundary when the pathname changes.
Thread feed and inspector guards apps/mobile/src/features/threads/ThreadDetailScreen.tsx, apps/mobile/src/features/threads/ThreadRouteScreen.tsx, apps/mobile/src/features/threads/thread-inspector-content-stack.tsx	Adds render boundaries for the thread feed and inspector panes. The reset keys use thread identity and working-directory values.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant Navigator
  participant GuardedScreenLayout
  participant RenderErrorBoundary
  participant ScreenRenderFallback
  participant RenderFailureView
  Navigator->>GuardedScreenLayout: supplies route and screen content
  GuardedScreenLayout->>RenderErrorBoundary: wraps content with route params as reset keys
  RenderErrorBoundary->>RenderErrorBoundary: captures a render error
  RenderErrorBoundary->>ScreenRenderFallback: renders route-aware fallback
  ScreenRenderFallback->>RenderFailureView: supplies error details and exit action

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Suggested reviewers: chrisdeeming, pixpmusic

Merge Risk: ⚪ Minimal · up to 05a54

The mobile recovery change is ready to merge after normal checks; no actionable issue is established by the supplied evidence.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 10 functions across 7 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: mobile screens recover from render errors.
Description check	✅ Passed	The description explains what changed, why it changed, the affected areas, UI behavior, screenshots, and verification results. It does not include the template checklist, and it notes that the persist…
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.

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