# Work does not honor its cancellation contract

Rule ID: concurrency.unresponsive-cancellation-work@1.0.0. Availability below refers to source-scan at product 524fa07e.

## V-ASYNC-10 — Work does not honor its cancellation contract

Work does not honor its cancellation contract. It examines task ordering, suspension, cancellation, progress, and async obligations.

### Availability

Not available in source-scan. There is no source-scan flag to activate this condition.

A separate [experimental source preview](https://docs.swift-analyzer.com/guides/experimental/) recognizes a limited local pattern for this condition:

```text
"$ANALYZER" experimental-scan <path> --rule async.swallowed-task-sleep-cancellation-loop --format json
```

Use 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.

### Example and action

Illustrative pattern only. This is not a complete runnable package or a reproduced source-scan result. Helper APIs and omitted context must be supplied by the application.

```swift
while true {
    try? await Task.sleep(for: .milliseconds(100))
    poll()
}
```

In this async throwing context, propagate cancellation instead of suppressing the error from Task.sleep. The surrounding caller must preserve that cancellation path. The experimental selector recognizes the swallowed-sleep loop form; cancellation responsiveness inside poll still depends on its implementation.

```swift
while true {
    try Task.checkCancellation()
    try await Task.sleep(for: .milliseconds(100))
    poll()
}
```

### Intended analysis

Intended 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

### Assumptions and unknown

The 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.

### Evidence and interpretation

The target catalog describes the intended condition. It is not evidence of an active source-scan diagnostic.

Historical evidence at 4558458d: recovery-required (historical qualification is incomplete and needs further evidence). That evidence has not been requalified for this product revision.

[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.


---

Language: en
Canonical: https://docs.swift-analyzer.com/catalog/concurrency.unresponsive-cancellation-work/
Product revision: 524fa07e0ae4153c84ac12ae9eb6559df89ec2be
Catalog revision: 4558458d
Documentation digest: 1f17ba58ab08627e0de898f1442067b09e960b48cd5605d6529e9275f8930d68
Channel: pre-prod; maturity: experimental; access: owner-provided checkout.