A deadline enforced by the backend could not arrive as an
OAuthRequestTimeoutError: /api/fetch serialized it as a 500 and
createRemoteFetch turned that into a plain Error, so every instanceof
check downstream was false — including the one that lets a stalled
probe escape withRfc8414OidcCompat. That matters most where no
client-side wrapper exists to have fired first: the discovery the SDK
runs from inside the transport. The route now answers 504 with a typed
marker (OAUTH_TIMEOUT_WIRE_CODE plus url and timeoutMs) and
createRemoteFetch reconstructs the error from it, guarded by a shape
check so an upstream's own JSON cannot forge one.
The route's deadline becomes a `fetchTimeoutMs` option defaulting to
the shared constant, so the backstop can be proven to fire in
milliseconds instead of thirty seconds of wall clock — and because a
very slow authorization server is a legitimate reason to want a longer
one.
The rounding rationale was wrong: setTimeout accepts a fractional delay
and truncates it (verified on Node 26); ERR_OUT_OF_RANGE is
AbortSignal.timeout's behaviour, which this wrapper never calls. The
rounding stays, for the reason that is actually true — the budget is
interpolated into the message and exposed as timeoutMs, and a
performance.now() budget would otherwise report 1000.4000000953674ms.
Also drops a sentence in the discarded-stream test that contradicted
the qualification above it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YFnM6RqB4nXqNysgUYmjmq
Signed-off-by: cliffhall <cliff@futurescale.com>