Negative encoding value crashes the decoder

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
84/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
swift
Domain
tooling

Research direction

Start in String.Encoding+JSONCodable.swift:107 and trace the numeric handling through Value.swift:94. Run the reproducer with negative and above-Int.max encoding values, then verify decoding throws an error instead of trapping and that xcprojformatter no longer exits with a crash.

Written by the indexing model from the issue text.

Description

A file reference with a negative encoding traps instead of throwing:

let json = #"{"default-configuration":"Debug","localizations":{"development":"en"},"files":[{"path":"a.txt","encoding":-1}]}"#
_ = try XCSchema.Project(jsonRepresentation: Data(json.utf8))
// Fatal error: Negative value is not representable

xcprojformatter dies the same way (exit 133).

It's UInt(Int(with: coder)) in String.Encoding+JSONCodable.swift:107. Values above Int.max (e.g. 9223372036854775808) crash too, because NSNumber.intValue in Value.swift:94 wraps them negative. UInt(exactly:) plus a thrown error would fix it.

main @ c132630, macOS 26, Swift 6.3.3

Dominant language
Swift
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Forks
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