{"schemaVersion":"2.0.0","locale":"en","title":"Continuation can resume more than once","description":"Rule ID: concurrency.double-continuation-resume@1.0.0. Availability below refers to source-scan at product 524fa07e.","htmlUrl":"https://docs.swift-analyzer.com/catalog/concurrency.double-continuation-resume/","markdownUrl":"https://docs.swift-analyzer.com/catalog/concurrency.double-continuation-resume/index.md","productRevision":"524fa07e0ae4153c84ac12ae9eb6559df89ec2be","catalogRevision":"4558458d","docsRevision":"1f17ba58ab08627e0de898f1442067b09e960b48cd5605d6529e9275f8930d68","channel":"pre-prod","maturity":"experimental","access":"owner-provided-checkout","markdown":"# Continuation can resume more than once\n\nRule ID: concurrency.double-continuation-resume@1.0.0. Availability below refers to source-scan at product 524fa07e.\n\n## V-ASYNC-07 — Continuation can resume more than once\n\nContinuation can resume more than once. It examines task ordering, suspension, cancellation, progress, and async obligations.\n\n### Availability\n\nNot available in source-scan. There is no source-scan flag to activate this condition.\n\nA separate [experimental source preview](https://docs.swift-analyzer.com/guides/experimental/) recognizes a limited local pattern for this condition:\n\n```text\n\"$ANALYZER\" experimental-scan <path> --rule async.continuation-double-resume --format json\n```\n\nUse the terminal from [Installation](https://docs.swift-analyzer.com/get-started/installation/), with ANALYZER set, and replace `<path>` with a Swift file or directory. This preview is not compiler-backed source-scan coverage.\n\n### Example and action\n\nIllustrative design scenario, not a runnable Swift example or a reproduced analyzer result. The stated availability and evidence boundaries still apply.\n\n**Before:** A success callback and a timeout both retain the same continuation and can each resume it.\n\nReview the following change against the contract and build variants described above.\n\n**After:** Give completion a single synchronized owner that atomically chooses the winning outcome. Resume once outside the protected state transition and release the losing callbacks; include cancellation in the same protocol.\n\n### Intended analysis\n\nIntended reasoning: Follow the relevant state, task or synchronization events across control-flow and suspension boundaries. The intended decision needs the complete event ordering and the operation contract; opaque events can leave the result unknown. Required evidence: task, suspension, cancellation, ordering, and progress facts\n\n### Assumptions and unknown\n\nThe relevant facts must be admitted for the selected immutable build world. Unknown aliases, external effects, unsupported source forms or incomplete consumers can prevent a conclusion. Availability in this workflow is stated above; the illustration does not expand that availability.\n\n### Evidence and interpretation\n\nThe target catalog describes the intended condition. It is not evidence of an active source-scan diagnostic.\n\nHistorical evidence at 4558458d: recovery-required (historical qualification is incomplete and needs further evidence). That evidence has not been requalified for this product revision.\n\n[How we validate checks](https://docs.swift-analyzer.com/concepts/validation/) explains the evidence boundary. [Foundations](https://docs.swift-analyzer.com/concepts/foundations/) separates method assumptions from implementation claims.\n","anchors":["continuation-can-resume-more-than-once","V-ASYNC-07","availability","example-and-action","intended-analysis","assumptions-and-unknown","evidence-and-interpretation"]}