Skip to content

Latest commit

 

History

History
37 lines (26 loc) · 2.42 KB

Filing Parser Bug Reports.md

File metadata and controls

37 lines (26 loc) · 2.42 KB

Filing Parser Bug Reports

Guide to provide steps for filing actionable bug reports for parser failures.

Reducing a test case requires the swift-parser-cli utility that you can build by checking out swift-syntax and running swift build --package-path SwiftParserCLI or openning the SwiftParserCLI package and building the swift-parser-cli target in Xcode.

Round-Trip Failure or Parser Crash

If you encounter a case where printing the parsed syntax tree does not reproduce the original source file, that’s a round-tripping failure and is considered a serious bug in SwiftSyntax – preserving the original source is a core principle of this library. To reproduce and reduce the failure, perform the following steps

  1. Reduce the failure by running 
    swift-parser-cli reduce /pth/to/file/that/does/not/roundtrip.swift
  2. File a bug report on https://github.com/swiftlang/swift-syntax/issues/new/choose with the reduced source code or fix the issue yourself by following the steps in doc:FixingBugs.

Parse of Valid Source Failed or Bad Diagnostic Produced

If you have source code that is parsed correctly by the current Swift compiler (and thus the old parser written in C++), but that is rejected by the new parser or if you think that a diagnostic produced by the new parser is not very helpful, perform the following steps to reduce the failure:

  1. Run the following command to see the diagnostics produced by the parser 
    swift-parser-cli print-diags /path/to/file.swift
  2. Remove as much code as possible from your test file and check if it still produces the same diagnostic.
  3. File a bug report on https://github.com/swiftlang/swift-syntax/issues/new/choose with the reduced source code or fix the issue yourself by following the steps in doc:FixingBugs.

Parse of Valid Source Code Produced an Invalid Syntax Tree

If you have valid source code that produced a syntax tree which doesn’t represent the source code’s semantics correctly, perform the following steps:

  1. Run the following command to print the parsed syntax tree 
    swift-parser-cli print-tree /path/to/file.swift
  2. Remove as much code as possible from your test file and check if it still produces the same invalid tree
  3. File a bug report on https://github.com/swiftlang/swift-syntax/issues/new/choose with the reduced source code or fix the issue yourself by following the steps in doc:FixingBugs.