Fall back when a bundle could not resolve Fungle's door offset

[greluc]

On 32-bit Among Us 2023.7.11, Fungle's doors are read from offset -1.

Why

#410 reads the Fungle's doors from mushroomDoor_isOpen and falls back to door_isOpen:

const isOpenOffset =
	map === MapType.FUNGLE
		? (this.offsets.mushroomDoor_isOpen ?? this.offsets.door_isOpen)
		: this.offsets.door_isOpen;

A bundle that could not resolve the field does not omit it, though — it publishes -1, which is the generator's marker for a lookup that failed. -1 is not nullish, so ?? hands it straight to the read.

One published bundle is in that state, and it is the one that matters: x86 V2023.7.11, which serves broadcast 50585000 — the build the Fungle arrived in. Its x64 sibling omits the field entirely and falls back correctly, which is why this shows only on 32-bit.

What changed

The field is used only when it actually resolved:

const mushroomDoorIsOpen = this.offsets.mushroomDoor_isOpen;
const isOpenOffset =
	map === MapType.FUNGLE && mushroomDoorIsOpen !== undefined && mushroomDoorIsOpen >= 0
		? mushroomDoorIsOpen
		: this.offsets.door_isOpen;

Verification

The decision is extracted from GameReader.ts and run over every bundle the mirror publishes that can load the map, so the same script runs against either revision.

bundle	nightly	this branch
x86 V2023.7.11 (broadcast 50585000)	uses -1	uses 20
x64 V2023.7.11	uses 32	uses 32
the other 14 bundles	real values	unchanged
a non-Fungle map	door_isOpen	door_isOpen

Sixteen bundles checked: one read from an unresolved offset before, none after.

lint, typecheck, format:check, verify:esm and build pass, and prettier reports the file unchanged. CI was run on a fork before this was opened — lint and both platform builds green.

Why here and not in the offsets repository

The -1 could be removed from that one bundle instead, and then ?? would do its job. Two reasons this is the better place:

• A corrected bundle does not reach a client that has already cached the old one. fetchOffsets serves the cache whenever the filename and offsetsVersion match, so the fix would arrive only after that version is bumped, and not at all for someone offline.
• The guard also covers any bundle that carries -1 later, which is the same failure returning by the same route.

Happy to send the data change as well if you would rather have both.

Limits, stated plainly

Nothing here was run against Among Us, so what is verified is which number the code selects, not what that number means once it is read. The offsets and the ?? />= 0 semantics are the whole of the claim.

Disclaimer

This change was written with AI assistance (Claude Code). The author reviewed it, and the before/after table is real output from a script driving the real function, not a description of what it should do. Please review it as you would any patch from a stranger; if something here is wrong I would rather hear it than have it merged.

🤖 Generated with Claude Code

[github-actions]

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• BetterCrewLink Unpacked 64bit.zip
• BetterCrewLink Installer Windows.zip
• BetterCrewLink Installer Linux.zip

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