[5.3][Parser/libSyntax] Avoid doing lookup for a previous parsed node when we are in backtracking mode #31718
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… we are in backtracking mode This both addresses a crash during incremental re-parse (rdar://57679731) and generally avoids violating invariants for interacting with the parser library.
…ssor introducer Previously it was backtracking for the duration of the whole property body which was preventing re-use of previously parsed nodes for incremental re-parsing.
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@swift-ci Please test |
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@swift-ci please nominate |
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windows error is unrelated: |
AnthonyLatsis
added
swift 5.3
🍒 release cherry pick
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Cherry-pick of #31685 for 5.3.
Explanation: Fixes a crash during SwiftSyntax incremental re-parsing that was found by the stress tester. The incremental parse was re-using previously parsed nodes while the parser was backtracking for property body parsing, which was violating some invariants of the libSyntax parsing mechanism. The change fixes this and also reduces parser backtracking until the accessor introducer, and not for the whole property body.
Scope of issue: Primarily affects SwiftSyntax usage with a minor and safe change to how property bodies are parsed.
Origination: Unclear. I suspect this has been an issue for a while.
Risk: Low. Changes are scoped to SwiftSyntax and to the parsing of property bodies.
Testing: Added regression tests.
Reviewer: Rintaro Ishizaki (@rintaro)
Resolves rdar://57679731