## Summary
Magic link login could appear completely broken: submitting your email
on the login page showed a stale "This email is unauthorized" error
instead of the "we've sent you a magic link" confirmation, even when the
address was fine.
This PR reverts
[#4215](https://github.com/triggerdotdev/trigger.dev/pull/4215) (whose
diagnosis and fix turned out to be wrong) and fixes the actual bug,
which was in how login errors are stored and consumed.
## Root cause
Two session bugs compounded on the login page:
- The `/login` loader read the flashed `auth:error` without committing
the session. A Remix flash is only consumed when the session is
committed after the read, so once any attempt flashed an error (for
example an address rejected on an instance with `WHITELISTED_EMAILS`
set), it stayed in the session cookie and reappeared on every later
`/login` visit, making successful attempts look like failures.
- The `/login/magic` action stored its validation and rate limit errors
with `session.set`, which survives every later read and commit, so those
errors stuck permanently.
[#4215](https://github.com/triggerdotdev/trigger.dev/pull/4215) had
instead diagnosed a server-only module leaking into the client bundle
and crashing navigation. Checking the shipped images' client bundles via
their sourcemaps shows `.server` modules were always stubbed out, so
that change fixed nothing and is reverted here.
## Fix
- `/login` reads the flashed error and commits the session when one was
present, so an error renders once and clears. The `redirectTo` branch
now surfaces the error too instead of leaving it in the cookie.
- `/login/magic` flashes its errors instead of `set`ting them.
Verified end-to-end on a live preview environment: a rejected address
shows the error once and a reload clears it; a valid address lands on
the confirmation screen with the address named; GitHub, Google, and SSO
login paths are untouched by this diff.
James Ritchie
32e5edbd04