Sync with upstream v3.1.3 + Gather patch#5
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Allows extension codecs to handle undefined values instead of
msgpack converting them to nil. Used by Gather's serialization
framework to preserve {a: undefined} round-trip fidelity.
Ports the undefined round-trip test from the original patch PR and adds a new reentrancy test verifying that allowUndefinedCustomEncoding is propagated through clone() when the encoder's reentrance guard fires.
The encoder variable was only assigned once; restructuring to declare it before the Box codec registration lets ESLint's prefer-const rule pass while keeping the test semantics identical (extensionCodec is a shared reference, so the Box codec registered afterward is still visible to the encoder at runtime).
gesposito
approved these changes
May 11, 2026
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Rebases our
allowUndefinedCustomEncodingpatch onto upstream v3.1.3.The PR diff shows only Gather-specific changes against the upstream baseline (
main-upstream= exact v3.1.3 tag):src/Encoder.ts— theallowUndefinedCustomEncodingoption (5 insertions)package.json— rename to@gathertown/msgpack, version3.1.3Original patch for comparison: #2
All 325 upstream tests pass.
Test Plan
npm testpasses (325/325)Note
Medium Risk
Changes how
undefinedis treated during encoding whenallowUndefinedCustomEncodingis enabled, which can affect on-the-wire serialization compatibility. Adds targeted tests, but consumers relying on defaultundefined→nil behavior should review usage.Overview
Renames the published package to
@gathertown/msgpackwhile keeping version3.1.3.Adds an opt-in
Encoderoption,allowUndefinedCustomEncoding, that stops treatingundefinedas MessagePack nil so extension codecs can custom-encode it; ensures this flag is preserved across encoderclone()reentrancy. UpdatesExtensionCodectests to cover encoding/decodingundefinedand the clone-propagation case.Reviewed by Cursor Bugbot for commit f04adc1. Bugbot is set up for automated code reviews on this repo. Configure here.