GetUserByAuthname / GetUserByContactNo / GetUserLogin discarded the
Scan error, so a database that could not answer — down, pool exhausted,
or booted without its config (2026-07-20) — came back as uid 0 and every
user was told their email was wrong.
One lookup, GetUserLogin, now returns an error; sql.ErrNoRows is "not
found" and anything else reaches the service, which answers 500 "Login
is temporarily unavailable" and logs the cause. 409 "Invalid Email" is
unchanged for a genuine no-match: the console reads that exact shape as
"not registered". NULL password/role columns scan through sql.Null* so
they do not become 500s.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
