fix mac os sandbox check slowness (#3879)

Alternative approach to #3875, also meant to address
#3871

We're currently looking at a field called Environment in the local
receipt to check whether the app is running in sandbox on macOS.

However, since it's an undocumented field, we can't trust that it will
always be there, so if the value is production then we check the
bundle's signature, which can be slow to run.

This PR changes that behavior so that we only perform that check if the
value for that variable isn't available, which would cause a receipt
parsing failure since it's marked as non-optional.

Still need to write tests for this, but it should be significantly
easier than for the other PR.

Sources/Misc/SandboxEnvironmentDetector.swift

@@ -50,7 +50,14 @@ final class BundleSandboxEnvironmentDetector: SandboxEnvironmentDetector {
         }
 
         #if os(macOS) || targetEnvironment(macCatalyst)
-            return !self.isProductionReceipt || !self.isMacAppStore
+        // this relies on an undocumented field in the receipt that provides the Environment.
+        // if it's not present, we go to a secondary check.
+        if let isProductionReceipt = self.isProductionReceipt {
+            return !isProductionReceipt
+        } else {
+            return !self.isMacAppStore
+        }
+
         #else
             return path.contains("sandboxReceipt")
         #endif
@@ -73,12 +80,14 @@ extension BundleSandboxEnvironmentDetector: Sendable {}
 
 private extension BundleSandboxEnvironmentDetector {
 
-    var isProductionReceipt: Bool {
+    var isProductionReceipt: Bool? {
         do {
-            return try self.receiptFetcher.fetchAndParseLocalReceipt().environment == .production
+            let receiptEnvironment = try self.receiptFetcher.fetchAndParseLocalReceipt().environment
+            guard receiptEnvironment != .unknown else { return nil } // don't make assumptions if we're not sure
+            return receiptEnvironment == .production
         } catch {
             Logger.error(Strings.receipt.parse_receipt_locally_error(error: error))
-            return false
+            return nil
         }
     }
 

Tests/UnitTests/Misc/SandboxEnvironmentDetectorTests.swift

@@ -45,7 +45,7 @@ class SandboxEnvironmentDetectorTests: TestCase {
 // `macOS` sandbox detection does not rely on receipt path
 class SandboxEnvironmentDetectorTests: TestCase {
 
-    func testIsNotSandboxIfReceiptIsProductionAndMAS() throws {
+    func testIsNotSandboxIfReceiptIsProduction() throws {
         expect(
             SystemInfo.with(
                 macAppStore: true,
@@ -54,41 +54,85 @@ class SandboxEnvironmentDetectorTests: TestCase {
         ) == false
     }
 
-    func testIsSandboxIfReceiptIsProductionAndNotMAS() throws {
+    func testIsSandboxIfReceiptIsNotProduction() throws {
         expect(
             SystemInfo.with(
                 macAppStore: false,
-                receiptEnvironment: .production
+                receiptEnvironment: .sandbox
             ).isSandbox
         ) == true
     }
 
-    func testIsSandboxIfReceiptIsNotProductionAndNotMAS() throws {
-        expect(
-            SystemInfo.with(
-                macAppStore: false,
-                receiptEnvironment: .sandbox
-            ).isSandbox
-        ) == true
+    func testIsSandboxWhenReceiptEnvironmentIsUnknownDefaultToMacAppStoreDetector() throws {
+        var isSandbox = false
+        var macAppStoreDetector = MockMacAppStoreDetector(isMacAppStore: !isSandbox)
+        var detector = SystemInfo.with(
+            macAppStore: !isSandbox,
+            receiptEnvironment: .unknown,
+            macAppStoreDetector: macAppStoreDetector
+        )
+
+        expect(detector.isSandbox) == isSandbox
+        expect(macAppStoreDetector.isMacAppStoreCalled) == true
+
+        isSandbox = !isSandbox
+
+        macAppStoreDetector = MockMacAppStoreDetector(isMacAppStore: !isSandbox)
+        detector = SystemInfo.with(
+            macAppStore: !isSandbox,
+            receiptEnvironment: .unknown,
+            macAppStoreDetector: macAppStoreDetector
+        )
+
+        expect(detector.isSandbox) == isSandbox
     }
 
-    func testIsSandboxIfReceiptIsNotProductionAndMAS() throws {
-        expect(
-            SystemInfo.with(
-                macAppStore: true,
-                receiptEnvironment: .sandbox
-            ).isSandbox
-        ) == true
+    func testIsSandboxWhenReceiptParsingFailsDefaultsToMacAppStoreDetector() throws {
+        var isSandbox = false
+        var macAppStoreDetector = MockMacAppStoreDetector(isMacAppStore: !isSandbox)
+        var detector = SystemInfo.with(
+            macAppStore: !isSandbox,
+            failReceiptParsing: true,
+            macAppStoreDetector: macAppStoreDetector
+        )
+
+        expect(detector.isSandbox) == isSandbox
+        expect(macAppStoreDetector.isMacAppStoreCalled) == true
+
+        isSandbox = !isSandbox
+
+        macAppStoreDetector = MockMacAppStoreDetector(isMacAppStore: !isSandbox)
+        detector = SystemInfo.with(
+            macAppStore: !isSandbox,
+            failReceiptParsing: true,
+            macAppStoreDetector: macAppStoreDetector
+        )
+
+        expect(detector.isSandbox) == isSandbox
     }
 
-    func testIsSandboxIfReceiptParsingFailsAndBundleSignatureIsNotMAS() throws {
-        expect(
-            SystemInfo.with(
-                macAppStore: false,
-                receiptEnvironment: .production,
-                failReceiptParsing: true
-            ).isSandbox
-        ) == true
+    func testIsSandboxWhenReceiptIsProductionReturnsProductionAndDoesntHitMacAppStoreDetector() throws {
+        let macAppStoreDetector = MockMacAppStoreDetector(isMacAppStore: false)
+        let detector = SystemInfo.with(
+            macAppStore: false,
+            receiptEnvironment: .production,
+            macAppStoreDetector: macAppStoreDetector
+        )
+
+        expect(detector.isSandbox) == false
+        expect(macAppStoreDetector.isMacAppStoreCalled) == false
+    }
+
+    func testIsSandboxWhenReceiptIsSandboxReturnsSandboxAndDoesntHitMacAppStoreDetector() throws {
+        let macAppStoreDetector = MockMacAppStoreDetector(isMacAppStore: false)
+        let detector = SystemInfo.with(
+            macAppStore: false,
+            receiptEnvironment: .sandbox,
+            macAppStoreDetector: macAppStoreDetector
+        )
+
+        expect(detector.isSandbox) == true
+        expect(macAppStoreDetector.isMacAppStoreCalled) == false
     }
 
 }
@@ -104,7 +148,8 @@ private extension SandboxEnvironmentDetector {
         inSimulator: Bool = false,
         macAppStore: Bool = false,
         receiptEnvironment: AppleReceipt.Environment = .production,
-        failReceiptParsing: Bool = false
+        failReceiptParsing: Bool = false,
+        macAppStoreDetector: MockMacAppStoreDetector? = nil
     ) -> SandboxEnvironmentDetector {
         let bundle = MockBundle()
         bundle.receiptURLResult = result
@@ -126,7 +171,7 @@ private extension SandboxEnvironmentDetector {
             isRunningInSimulator: inSimulator,
             receiptFetcher: MockLocalReceiptFetcher(mockReceipt: mockReceipt,
                                                     failReceiptParsing: failReceiptParsing),
-            macAppStoreDetector: MockMacAppStoreDetector(isMacAppStore: macAppStore)
+            macAppStoreDetector: macAppStoreDetector ?? MockMacAppStoreDetector(isMacAppStore: macAppStore)
         )
     }
 
@@ -151,12 +196,17 @@ private final class MockLocalReceiptFetcher: LocalReceiptFetcherType {
 
 }
 
-private struct MockMacAppStoreDetector: MacAppStoreDetector {
+private final class MockMacAppStoreDetector: MacAppStoreDetector, @unchecked Sendable {
 
-    let isMacAppStore: Bool
+    let isMacAppStoreValue: Bool
+    private(set) var isMacAppStoreCalled = false
 
     init(isMacAppStore: Bool) {
-        self.isMacAppStore = isMacAppStore
+        self.isMacAppStoreValue = isMacAppStore
     }
 
+    var isMacAppStore: Bool {
+        isMacAppStoreCalled = true
+        return isMacAppStoreValue
+    }
 }