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Fix DNS preference continuation leak #3

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Merged
offyotto merged 1 commit into from
Jun 6, 2026
Merged

Fix DNS preference continuation leak #3

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62 changes: 54 additions & 8 deletions Sources/LocaleApp/DNSProxyController.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,7 @@ actor DNSProxyController {
let manager = NEDNSProxyManager.shared()

do {
try await manager.loadFromPreferences()
try await manager.loadFromPreferencesWithTimeout()
let providerProtocol = NEDNSProxyProviderProtocol()
providerProtocol.providerBundleIdentifier = LocaleDNSConstants.extensionBundleIdentifier
providerProtocol.serverAddress = "Locale DNS Proxy"
Expand All @@ -59,7 +59,7 @@ actor DNSProxyController {
manager.localizedDescription = "Locale"
manager.providerProtocol = providerProtocol
manager.isEnabled = isEnabled
try await manager.saveToPreferences()
try await manager.saveToPreferencesWithTimeout()
} catch {
throw DNSProxyControllerError.preferencesFailed(error.localizedDescription)
}
Expand Down Expand Up @@ -157,27 +157,73 @@ private final class SystemExtensionRequestDelegate: NSObject, OSSystemExtensionR
}

private extension NEDNSProxyManager {
func loadFromPreferences() async throws {
func loadFromPreferencesWithTimeout() async throws {
try await withCheckedThrowingContinuation { (continuation: CheckedContinuation<Void, Error>) in
let operation = PreferenceOperationContinuation(continuation: continuation, operationName: "load DNS proxy preferences")
operation.scheduleTimeout()
loadFromPreferences { error in
if let error {
continuation.resume(throwing: error)
operation.resume(throwing: error)
} else {
continuation.resume()
operation.resume()
}
}
}
}

func saveToPreferences() async throws {
func saveToPreferencesWithTimeout() async throws {
try await withCheckedThrowingContinuation { (continuation: CheckedContinuation<Void, Error>) in
let operation = PreferenceOperationContinuation(continuation: continuation, operationName: "save DNS proxy preferences")
operation.scheduleTimeout()
saveToPreferences { error in
if let error {
continuation.resume(throwing: error)
operation.resume(throwing: error)
} else {
continuation.resume()
operation.resume()
}
}
}
}
}

private final class PreferenceOperationContinuation: @unchecked Sendable {
private let lock = NSLock()
private var continuation: CheckedContinuation<Void, Error>?
private let operationName: String

init(continuation: CheckedContinuation<Void, Error>, operationName: String) {
self.continuation = continuation
self.operationName = operationName
}

func scheduleTimeout() {
DispatchQueue.main.asyncAfter(deadline: .now() + 10) { [weak self] in

@chatgpt-codex-connector chatgpt-codex-connector Bot Jun 5, 2026

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P1 Badge Retain the timeout operation until it fires

When loadFromPreferences/saveToPreferences never invoke or retain the completion handler, the only reference left to PreferenceOperationContinuation is this weak capture, so it can be deallocated before the 10-second deadline and the timeout block returns without resuming the checked continuation. That leaves Apply/Revert suspended and preserves the continuation leak in exactly the entitlement/provisioning failure path this change is trying to handle; the timeout closure needs to keep the operation alive until it either fires or an earlier callback clears the continuation.

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guard let self else { return }
self.resume(
throwing: DNSProxyControllerError.preferencesFailed(
"Timed out while trying to \(self.operationName). Check that Locale is signed with the DNS Proxy Network Extension entitlement."
)
)
}
}

func resume() {
finish { $0.resume() }
}

func resume(throwing error: Error) {
finish { $0.resume(throwing: error) }
}

private func finish(_ resume: (CheckedContinuation<Void, Error>) -> Void) {
lock.lock()
guard let continuation else {
lock.unlock()
return
}
self.continuation = nil
lock.unlock()

resume(continuation)
}
}
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