Unicode 15 scripts and blocks are unrecognized

[benrimmington]

The standard library was updated (by @Azoy) to use Unicode 15 data. Should the MissingUnicode.swift APIs also be updated?

/\p{Script=Arabic}/   // OK
/\p{Script=Kawi}/     // error: unrecognized script 'Kawi'

/\p{Block=Arabic}/    // error: Unicode block property is not currently supported
/\p{Block=Kawi}/      // error: unrecognized block 'Kawi'

(Old blocks are unsupported. New blocks are unrecognized.)

[benrimmington]

Unrecognized names such as /\N{LOREM IPSUM}/ and /\p{Name=LOREM IPSUM}/ are allowed. However, unrecognized scripts and blocks are currently a compile-time and run-time error. This suggests that back-deployment of Regex literals might be a problem?

import Foundation

do {
  try Regex(#"\p{Script=Kawi}"#)
} catch {
  error.localizedDescription
}

The localized error description is unhelpful:

The operation couldn’t be completed. (_RegexParser.Source.LocatedError<_RegexParser.Diagnostics.(unknown context at $23808a414).(unknown context at $23808a41c).ErrorDiagnostic> error 1.)

[benrimmington]

This issue was fixed in pull request #808. However, I'm still worried about back-deployment of Regex literals. Are there compile-time availability checks for the Unicode 15 and 16 scripts? Or will the Swift 5.7 runtime crash, due to an "unrecognized script" fatal error?

Cc: @Azoy @milseman @natecook1000 @stephentyrone

[benrimmington]

The /\p{Script=Kawi}/ regex literal now compiles, but then crashes at runtime on the previous macOS version.

_StringProcessing/Core.swift:107: Fatal error: 'try!' expression unexpectedly raised an error: unrecognized script 'Kawi'

• Xcode 16.3 (16E140)
• macOS Sequoia 15.3.2 (24D81)