BREAKING CHANGE: keyDir now defaults to null (ephemeral) instead of
'client_keys'. Clients that relied on keys persisting across restarts
must now pass keyDir explicitly.
The Python SDK defaults to key_dir=None: a key pair is generated in
memory for the session and never written to disk. The JS port defaulted
to 'client_keys' and always persisted, so merely constructing a client
wrote an RSA private key into the working directory. That is a weaker
default than the client it ports, and one users never asked for.
- keyDir?: string | null, defaulting to undefined. null and undefined
both mean ephemeral, matching Python's None.
- Persistent mode is unchanged when keyDir is set: load the existing
pair from that directory, otherwise generate and save one there.
- Browsers are always ephemeral; they have no filesystem.
Key rotation follows the same rule. It previously hardcoded
'client_keys' as its fallback directory, so an ephemeral client would
have started writing private keys to disk on the first rotation tick.
Rotated keys are now persisted only where keyDir or keyRotationDir is
explicitly configured.
Tests assert the intent (that saveKeys is never called) rather than
probing the filesystem, since a leftover client_keys/ from the old
default would otherwise make them pass or fail for the wrong reason.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
