Runtime crash when accessing DSL-composed Regex Match with named capture groups #625
Description
Description
Composing a Regex with the DSL using RegexLiterals with named capture groups works, and matching works, but accessing the matches crashes at runtime.
Using the same patterns in RegexLiteral & DSL without the names works fine.
forum.swift.org: runtime-crash-regexbuilding-with-regex-literals-containing-named-capture-groups/62539
Steps to reproduce
Define one or more patterns with named capture groups, and use the DSL to compose a Regex. Match (whole, prefix, etc.) to a string. The the pattern matches correctly, but accessing the Output causes a runtime crash.
enum FrameComponentRegex { static let number = /frame \#(?<frame_number>\d+):/ static let address = /(?<frame_address>\dx\w{16})/ static let module = /(?<frame_module>\w+\.{0,1}\w+)/ static let function = /(?<frame_function>.+)/ } let frame = Regex { FrameComponentRegex.number One(.whitespace) FrameComponentRegex.address One(.whitespace) FrameComponentRegex.module One("`") FrameComponentRegex.function } let frameString = """ frame apple/swift#10: 0x00007fff2011383a libdispatch.dylib`_dispatch_client_callout + 8 """ if let match = frameString.wholeMatch(of: frame) { print(match) /** Match(anyRegexOutput: _StringProcessing.AnyRegexOutput( input: "frame apple/swift#10: 0x00007fff2011383a libdispatch.dylib`_dispatch_client_callout + 8", _elements: [ _StringProcessing.AnyRegexOutput.ElementRepresentation(optionalDepth: 0, content: Optional((range: Range(Swift.String.Index(_rawBits: 15)..<Swift.String.Index(_rawBits: 4980743)), value: nil)), name: nil, referenceID: nil), _StringProcessing.AnyRegexOutput.ElementRepresentation(optionalDepth: 0, content: Optional((range: Range(Swift.String.Index(_rawBits: 458757)..<Swift.String.Index(_rawBits: 590087)), value: nil)), name: Optional("frame_number"), referenceID: nil), _StringProcessing.AnyRegexOutput.ElementRepresentation(optionalDepth: 0, content: Optional((range: Range(Swift.String.Index(_rawBits: 721159)..<Swift.String.Index(_rawBits: 1900807)), value: nil)), name: Optional("frame_address"), referenceID: nil), _StringProcessing.AnyRegexOutput.ElementRepresentation(optionalDepth: 0, content: Optional((range: Range(Swift.String.Index(_rawBits: 1966343)..<Swift.String.Index(_rawBits: 3080455)), value: nil)), name: Optional("frame_module"), referenceID: nil), _StringProcessing.AnyRegexOutput.ElementRepresentation(optionalDepth: 0, content: Optional((range: Range(Swift.String.Index(_rawBits: 3145733)..<Swift.String.Index(_rawBits: 4980743)), value: nil)), name: Optional("frame_function"), referenceID: nil) ]), range: Range(Swift.String.Index(_rawBits: 15)..<Swift.String.Index(_rawBits: 4980743))) **/ let _ = match.output /** Runtime crash Could not cast value of type '(Swift.Substring, Swift.Substring, Swift.Substring, Swift.Substring, Swift.Substring)' (0x7ff848f83d00) to 'Swift.Substring' (0x7ff848af00c8). **/ let (_, number, address, module, function) = match.output /** Compiler exception Type of expression is ambiguous without more context **/ Expected behavior
It should be possible to access the captures via tuple. It would be nice to also have subscript-based access, but that's a separate issue.
enum FrameComponentRegex_Unnamed { static let number = /frame \#(\d+):/ static let address = /(\dx\w{16})/ static let module = /(\w+\.{0,1}\w+)/ static let function = /(.+)/ } if let match = frameString.wholeMatch(of: frame) { let (_, number, address, module, function) = match.output print(""" number: \(number) address: \(address) module: \(module) function: \(function) """) } /** number: 10 address: 0x00007fff2011383a module: libdispatch.dylib function: _dispatch_client_callout + 8 **/ Environment
- Swift compiler version info
swift-driver version: 1.62.15 Apple Swift version 5.7.1 (swiftlang-5.7.1.135.3 clang-1400.0.29.51) - Xcode version info
Version 14.1 (14B47b) - Deployment target:
macOS 13.0