Both sides of the signal channel previously broke their recv loop
on any deserialize error, which meant adding a new variant in one
build silently killed signal connections from peers running an
older build. This bit us during Phase 1 testing: a new client
sending SignalMessage::Reflect to a pre-Phase-1 relay caused the
relay to drop the whole signal connection, which looked like
"Error: not registered" on the next place_call.
Fix:
- New TransportError::Deserialize(String) variant in wzp-proto
carries serde errors as a distinct category.
- wzp-transport/reliable.rs::recv_signal returns Deserialize on
serde_json::from_slice failures (was wrapped in Internal).
- wzp-relay/main.rs signal loop matches on Deserialize → warn +
continue (instead of break).
- desktop/src-tauri/lib.rs recv loop does the same.
Other TransportError variants (ConnectionLost, Io, Internal) still
break the loop — only pure parse failures are recoverable.
This means future SignalMessage variant additions are backward-
compat by construction: older peers will see "unknown variant,
continuing" in their logs while newer peers can keep evolving the
protocol.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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