Two kinds of noisy warnings appear every time an invitee or a
restarted client catches up with events still sitting on the relays.
Both are actually expected, per-spec behavior — not errors.
(a) Outer ChaCha20-Poly1305 decrypt fails with "current and N
retained epoch key(s)".
A newly-joined member processes the three kind:445s that
advanced the group to their current epoch (add-me-commit plus
any earlier commits). The commits were outer-encrypted with
keys that predate their Welcome, so they never held them — this
is MLS forward secrecy working as intended. No state on the
receiver's side actually needs to update: they're already at
the post-Welcome epoch.
(b) "NO matching KeyPackageBundle for eventId=…" after app restart.
The gift-wrapped Welcome (kind:1059) is still on the relay and
gets redelivered on every subscription refresh. The client's
`processedEventIds` dedup set is in-memory, so after a restart
the Welcome flows all the way to `processWelcome`, which then
fails to find the KeyPackage bundle because it was consumed and
marked during the first processing.
Both of these fire every time a member opens the app, so the logs
currently look like something is broken even when everything is
behaving correctly.
Fix:
- Add `GroupEventResult.UndecryptableOuterLayer(groupId,
retainedEpochCount)`. `MarmotInboundProcessor.processGroupEvent`
and `applyCommit` now call the new `tryDecryptOuterLayer` (which
returns `ByteArray?` instead of throwing) and surface this
variant when every available key fails. `GroupEventHandler.add`
logs it at DEBUG with a one-liner noting "likely from before our
join".
- Add `WelcomeResult.AlreadyJoined(nostrGroupId)`. When
`MarmotInboundProcessor.processWelcome` is called with a
`hintNostrGroupId` we're already a member of, short-circuit
before the KeyPackageBundle lookup and return `AlreadyJoined`.
`processMarmotWelcomeFlow` logs at DEBUG.
- `MarmotManager.processGroupEvent` treats `UndecryptableOuterLayer`
as a no-op for subscription-timestamp updates (same as
Duplicate/Error/CommitPending), so a unreadable past-epoch event
doesn't move the group's `since` forward.
No behavioral changes beyond logging level and the short-circuit of
a Welcome we already processed (which was throwing and returning
Error before). Existing callers that only care about successful
`Joined` / successful `CommitProcessed` / `ApplicationMessage`
branches are unaffected — the two new variants join the
`Duplicate` / `CommitPending` / `Error` quiet side of the sealed
class.
https://claude.ai/code/session_014zfdNeeKAfU1zGGyFw4bUL
Claude
96cedcbc9b