refactor(ui): extract extension runtime lifecycle

[benvinegar]

Summary

• move extension runtime authority and command context construction out of App
• install event-context providers only after commit and retire stale capabilities during layout cleanup
• preserve frozen command selection, live navigation, and soft- and hard-reload authority

Testing

• focused runtime bridge, provider lifecycle, and command runner tests
• relevant App and AppHost extension lifecycle tests
• PTY extension integration tests
• bun run typecheck
• bun run deps:check
• bun run lint
• targeted formatting and diff checks

Stack

• Builds on refactor(ui): isolate extension pane controller #881
• Final PR in the stack

This PR description was generated by Pi using GPT-5.6 Sol

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
hunk-web	Ignored	Preview	Aug 27, 2026 12:14pm

[greptile-apps]

Greptile Summary

The PR extracts extension command execution, event-context installation, and runtime capability lifecycle management from App into focused hooks.

• Introduces a runtime bridge for committed selection projections, command/navigation bindings, and capability retirement.
• Moves extension command context construction and error containment into a dedicated hook.
• Installs event contexts during layout commit with identity-checked cleanup.
• Adds focused tests for StrictMode, reload, remount, registry replacement, selection snapshots, and command failures.

Confidence Score: 4/5

The PR appears safe to merge, with only a non-blocking test-fixture typing issue to address.

The extracted runtime lifecycle preserves committed-state ordering and stale-capability retirement, while the only accepted concern is that new tests bypass structural fixture checking through empty-object type assertions.

Files Needing Attention: src/ui/hooks/useExtensionCommandRunner.test.tsx and src/ui/hooks/useExtensionEventContextProvider.test.tsx

Important Files Changed

Filename	Overview
src/ui/hooks/useExtensionRuntimeBridge.ts	Centralizes committed extension state, selection projections, capability leases, and command/navigation bindings with lifecycle-focused tests.
src/ui/hooks/useExtensionCommandRunner.ts	Extracts command-context construction and consistently contains synchronous, asynchronous, and context-construction failures.
src/ui/hooks/useExtensionEventContextProvider.ts	Installs event contexts during layout commit and prevents stale cleanup from removing a successor provider.
src/ui/App.tsx	Replaces inline extension lifecycle machinery with the three extracted hooks while retaining host composition responsibilities.
src/ui/hooks/useExtensionCommandRunner.test.tsx	Thoroughly covers command context and failure containment, but its partial fixtures bypass the repository’s required typed fixture helper.
src/ui/hooks/useExtensionEventContextProvider.test.tsx	Covers commit timing, StrictMode, replacement, and cleanup while repeating the partial-fixture assertion issue.
src/ui/hooks/useExtensionRuntimeBridge.test.tsx	Exercises retirement and liveness across StrictMode, hard remounts, content reloads, registry replacement, and selection changes.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart LR
  App[App render] --> Bridge[Extension runtime bridge]
  App --> Runner[Command runner]
  App --> Provider[Event context provider]
  App --> Bindings[Command and navigation bindings]
  Bindings -->|layout commit| Bridge
  Bridge --> Lease[Registry and review leases]
  Bridge --> Projection[Committed and render projections]
  Runner --> Context[Extension command context]
  Provider --> Events[Lifecycle and custom events]
  Lease -->|reload or unmount| Retired[Retired controls become inert]

Loading

Prompt To Fix All With AI

### Issue 1
src/ui/hooks/useExtensionCommandRunner.test.tsx:20
**Partial mocks bypass typing**

The new hook tests construct partial extension-capability fixtures with `{} as ...` assertions instead of the required `@total-typescript/shoehorn` helpers. This bypasses structural checking and allows capability contracts to change without useful compile-time failures; the same pattern appears in `useExtensionEventContextProvider.test.tsx`.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "refactor(ui): isolate extension runtime ..." | Re-trigger Greptile}

[greptile-apps]

Partial mocks bypass typing

The new hook tests construct partial extension-capability fixtures with {} as ... assertions instead of the required @total-typescript/shoehorn helpers. This bypasses structural checking and allows capability contracts to change without useful compile-time failures; the same pattern appears in useExtensionEventContextProvider.test.tsx.

Context Used: testing.mdc Cursor rule (source)

Prompt To Fix With AI

This is a comment left during a code review.
Path: src/ui/hooks/useExtensionCommandRunner.test.tsx
Line: 20

Comment:
**Partial mocks bypass typing**

The new hook tests construct partial extension-capability fixtures with `{} as ...` assertions instead of the required `@total-typescript/shoehorn` helpers. This bypasses structural checking and allows capability contracts to change without useful compile-time failures; the same pattern appears in `useExtensionEventContextProvider.test.tsx`.

**Context Used:** testing.mdc Cursor rule ([source](https://github.com/modem-dev/modem/blob/main/.cursor/rules/testing.mdc))

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!