Clear the key packages and app config on ENError = 2

src/xcode/ENA/ENA/Source/AppDelegate.swift

@@ -23,7 +23,7 @@ import UIKit
 protocol CoronaWarnAppDelegate: AnyObject {
 	var client: HTTPClient { get }
 	var downloadedPackagesStore: DownloadedPackagesStore { get }
-	var store: Store { get }
+	var store: Store & AppConfigCaching { get }
 	var appConfigurationProvider: AppConfigurationProviding { get }
 	var riskProvider: RiskProvider { get }
 	var exposureManager: ExposureManager { get }
@@ -99,7 +99,7 @@ extension AppDelegate: ExposureSummaryProvider {
 @UIApplicationMain
 class AppDelegate: UIResponder, UIApplicationDelegate {
 
-	let store: Store
+	let store: Store & AppConfigCaching
 	let serverEnvironment: ServerEnvironment
 
 	private let consumer = RiskConsumer()
@@ -109,11 +109,6 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 		// use a custom http client that uses/recognized caching mechanisms
 		let appFetchingClient = CachingHTTPClient(clientConfiguration: client.configuration)
 
-		// we currently use the store as common place for temporal persistency
-		guard let store = store as? AppConfigCaching else {
-			preconditionFailure("Ensure to provide a proper app config cache")
-		}
-
 		return CachedAppConfiguration(client: appFetchingClient, store: store)
 	}()
 

src/xcode/ENA/ENA/Source/Services/DownloadedPackagesStore/__tests__/DownloadedPackagesSQLLiteStoreTests.swift

@@ -235,4 +235,39 @@ final class DownloadedPackagesSQLLiteStoreTests: XCTestCase {
 		XCTAssertEqual(store.allDays(country: "DE").count, 7)
 		XCTAssertEqual(store.allDays(country: "IT").count, 2)
 	}
+
+	func test_ResetRemovesAllKeys() {
+		let database = FMDatabase.inMemory()
+		let store = DownloadedPackagesSQLLiteStore(database: database, migrator: SerialMigratorFake(), latestVersion: 0)
+		store.open()
+
+		let keysBin = Data("keys".utf8)
+		let signature = Data("sig".utf8)
+
+		let package = SAPDownloadedPackage(
+			keysBin: keysBin,
+			signature: signature
+		)
+
+		// Add days
+		store.set(country: "DE", day: "2020-06-01", package: package)
+		store.set(country: "DE", day: "2020-06-02", package: package)
+		store.set(country: "DE", day: "2020-06-03", package: package)
+		store.set(country: "IT", day: "2020-06-03", package: package)
+		store.set(country: "DE", day: "2020-06-04", package: package)
+		store.set(country: "DE", day: "2020-06-05", package: package)
+		store.set(country: "DE", day: "2020-06-06", package: package)
+		store.set(country: "IT", day: "2020-06-06", package: package)
+		store.set(country: "DE", day: "2020-06-07", package: package)
+
+		XCTAssertEqual(store.allDays(country: "DE").count, 7)
+		XCTAssertEqual(store.allDays(country: "IT").count, 2)
+
+		store.reset()
+		store.open()
+
+		XCTAssertEqual(store.allDays(country: "DE").count, 0)
+		XCTAssertEqual(store.allDays(country: "IT").count, 0)
+		XCTAssertEqual(database.lastErrorCode(), 0)
+	}
 }

src/xcode/ENA/ENA/Source/Services/Exposure Transaction/ExposureDetectionExecutor.swift

@@ -11,13 +11,13 @@ final class ExposureDetectionExecutor: ExposureDetectionDelegate {
 	private let client: Client
 
 	private let downloadedPackagesStore: DownloadedPackagesStore
-	private let store: Store
+	private let store: Store & AppConfigCaching
 	private let exposureDetector: ExposureDetector
 
 	init(
 		client: Client,
 		downloadedPackagesStore: DownloadedPackagesStore,
-		store: Store,
+		store: Store & AppConfigCaching,
 		exposureDetector: ExposureDetector
 	) {
 		self.client = client
@@ -168,11 +168,26 @@ final class ExposureDetectionExecutor: ExposureDetectionDelegate {
 			writtenPackages: WrittenPackages,
 			completion: @escaping (Result<ENExposureDetectionSummary, Error>) -> Void
 	) -> Progress {
+
+		// Clear the key packages and app config on ENError = 2 = .badParameter
+		// For more details, see: https://jira.itc.sap.com/browse/EXPOSUREAPP-3297
+		func clearCacheOnError2(error: Error) {
+			if let enError = error as? ENError, enError.code == .badParameter {
+				// Clear the key packages
+				downloadedPackagesStore.reset()
+				downloadedPackagesStore.open()
+
+				// Clear the app config
+				store.appConfig = nil
+			}
+		}
+
 		func withResultFrom(
 				summary: ENExposureDetectionSummary?,
 				error: Error?
 		) -> Result<ENExposureDetectionSummary, Error> {
 			if let error = error {
+				clearCacheOnError2(error: error)
 				return .failure(error)
 			}
 			if let summary = summary {

src/xcode/ENA/ENA/Source/Services/Exposure Transaction/__tests__/ExposureDetectionExecutorTests.swift

@@ -368,6 +368,53 @@ final class ExposureDetectionExecutorTests: XCTestCase {
 		)
 		waitForExpectations(timeout: 2.0)
 	}
+
+	func testDetectSummaryWithConfiguration_Error2BadParameter_ClearsCache() throws {
+		// Test the case where the exector is asked to run an exposure detection
+		// We provide an `MockExposureDetector` with an error, and expect this to be returned
+		let completionExpectation = expectation(description: "Expect that the completion handler is called.")
+		let expectedError = ENError(.badParameter)
+
+		let keysBin = Data("keys".utf8)
+		let signature = Data("sig".utf8)
+		let package = SAPDownloadedPackage(
+			keysBin: keysBin,
+			signature: signature
+		)
+		let packageStore = DownloadedPackagesSQLLiteStore.inMemory()
+		packageStore.open()
+		packageStore.set(country: "DE", day: "SomeDay", package: package)
+
+		let store = MockTestStore()
+		store.appConfig = SAP_ApplicationConfiguration()
+
+		let sut = ExposureDetectionExecutor.makeWith(
+			packageStore: packageStore,
+			store: store,
+			exposureDetector: MockExposureDetector((nil, expectedError))
+		)
+		let exposureDetection = ExposureDetection(
+			delegate: sut,
+			appConfigurationProvider: AppConfigurationProviderFake()
+		)
+
+		XCTAssertNotEqual(packageStore.allDays(country: "DE").count, 0)
+		XCTAssertNotNil(store.appConfig)
+
+		sut.exposureDetection(
+			exposureDetection,
+			detectSummaryWithConfiguration: ENExposureConfiguration(),
+			writtenPackages: WrittenPackages(urls: []),
+			completion: { result in
+
+				XCTAssertEqual(packageStore.allDays(country: "DE").count, 0)
+				XCTAssertNil(store.appConfig)
+
+				completionExpectation.fulfill()
+			}
+		)
+		waitForExpectations(timeout: 2.0)
+	}
 }
 
 // MARK: - Private Helper Extensions
@@ -377,7 +424,7 @@ private extension ExposureDetectionExecutor {
 	static func makeWith(
 		client: Client = ClientMock(),
 		packageStore: DownloadedPackagesStore = DownloadedPackagesSQLLiteStore.inMemory(),
-		store: Store = MockTestStore(),
+		store: Store & AppConfigCaching = MockTestStore(),
 		exposureDetector: MockExposureDetector = MockExposureDetector()
 	) -> ExposureDetectionExecutor {
 		ExposureDetectionExecutor(