Blocking call on a critical executor

Rule ID: concurrency.main-actor-blocking@1.0.0. Availability below refers to source-scan at product 524fa07e.

V-EXEC-09 — Blocking call on a critical executor#

Blocking call on a critical executor. It examines isolation, executor, scheduler, and execution-domain relationships.

Availability#

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

A separate experimental source preview recognizes a limited local pattern for this condition:

text

"$ANALYZER" experimental-scan <path> --rule execution.blocking-in-concurrency-context --format json

Use the terminal from 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

@MainActor func refresh() {
    Thread.sleep(forTimeInterval: 2)
}

Make the required context explicit at the boundary. Review ordering, lifetime and transferred values before adding a task or changing isolation.

swift

@MainActor func refresh() async throws {
    try await Task.sleep(for: .seconds(2))
}

Intended analysis#

Intended reasoning: Compare the required execution or isolation context with recognized context transitions and use sites. Actor context, task context and physical thread identity are different facts; suspension alone does not prove a thread hop. Required evidence: isolation, executor, scheduler, and path 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 explains the evidence boundary. Foundations separates method assumptions from implementation claims.