Implement completeAuth chokepoint + caller migration
Implements all of unify-auth-completion (12/14 tasks done; manual
smoke + archive-time spec sync remain).
Design refinement during implementation: completeAuth supports two
response shapes via a `mode` parameter:
- mode: 'redirect' (loaders / direct browser navigation; auth.verify.tsx)
- mode: 'json' (action handlers called by imperative fetch from
client forms; api.auth.login, api.auth.register)
Both modes share createSession + safeReturnTo + Set-Cookie. JSON mode
carries `{ ok: true, step: "done", redirectTo }` (the `step` field
preserves the existing client-form check).
Why two modes: passkey ceremonies are inherently imperative
(start → browser WebAuthn API → finish), so action handlers can't
move to <Form>/useFetcher. Picking option (B) from the design grill —
the chokepoint owns destination selection while clients navigate —
required this dual shape. The 3 hardcoded client-side targets
(returnTo ?? "/", "/", "/?add-passkey=1") collapse into 1 server-side
sanitization pass (safeReturnTo) inside completeAuth.
New module:
- apps/journal/app/lib/auth/session.ts: cookie session storage
(sessionStorage, createSession, getSessionUser, destroySession)
moved from auth.server.ts. Legacy import path kept via re-exports
with @deprecated JSDoc.
- apps/journal/app/lib/auth/completion.ts: completeAuth + safeReturnTo.
- apps/journal/app/lib/auth/completion.test.ts: 10 contract tests
covering both modes, returnTo sanitization (path-relative, protocol-
relative, absolute-URL, malformed), Set-Cookie attachment, redirect
status, JSON shape.
Caller migration:
- api.auth.register.ts passkey-finish → completeAuth(json)
- api.auth.login.ts finish-passkey → completeAuth(json)
- api.auth.login.ts verify-code → completeAuth(json)
- auth.verify.tsx magic-link consumer → completeAuth(redirect)
Client form updates:
- auth.login.tsx: pass returnTo in fetch body, read result.redirectTo
on done.
- auth.register.tsx: pass returnTo: "/?add-passkey=1" for the magic-
link verify-code path (preserves the post-register passkey prompt
via the chokepoint's safeReturnTo, instead of hardcoding it
client-side).
Verified:
- pnpm typecheck && pnpm lint: green across all 15 workspaces.
- pnpm --filter @trails-cool/journal test: 126 passed.
- pnpm test:e2e auth: 4/4 passed without modification — confirms the
refactor is behaviour-preserving for the user-facing flows that
matter most (passkey register + login).
Spec delta in openspec/changes/unify-auth-completion/specs/ applies at
/opsx:archive time.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
d64c47614d