[iOS] Fix data race in PersistentFileLogSpec.swift

packages/expo-modules-core/CHANGELOG.md

@@ -15,6 +15,7 @@
 - [Android] Fix `getContext().getNativeModule(UIManagerModule.class)` in Bridgeless. ([#29203](https://github.com/expo/expo/pull/29203) by [@arushikesarwani94](https://github.com/arushikesarwani94))
 - [Android] Fixed converting from `null` to `Record` sometimes didn't work as expected. ([#29508](https://github.com/expo/expo/pull/29508) by [@lukmccall](https://github.com/lukmccall))
 - [Android] Fixed `No implementation found for com.facebook.jni.HybridData expo.modules.kotlin.jni.JavaScriptModuleObject.initHybrid`. ([#29513](https://github.com/expo/expo/pull/29513) by [@lukmccall](https://github.com/lukmccall))
+- [iOS] Fix data race in `PersistentFileLogSpec.swift`. ([#28924](https://github.com/expo/expo/pull/28924) by [@hakonk](https://github.com/hakonk))
 
 ### 💡 Others
 

packages/expo-modules-core/ios/Tests/PersistentFileLogSpec.swift

@@ -48,26 +48,57 @@ class PersistentFileLogSpec: ExpoSpec {
   }
 
   static func clearEntriesSync(log: PersistentFileLog) {
-    var didClear = false
+    let didClear = Synchronized(false)
     log.clearEntries { _ in
-      didClear = true
+      didClear.value = true
     }
-    expect(didClear).toEventually(beTrue(), timeout: .milliseconds(500))
+    expect(didClear.value).toEventually(beTrue(), timeout: .milliseconds(500))
   }
 
   static func filterEntriesSync(log: PersistentFileLog, filter: @escaping PersistentFileLogFilter) {
-    var didPurge = false
+    let didPurge = Synchronized(false)
     log.purgeEntriesNotMatchingFilter(filter: filter) { _ in
-      didPurge = true
+      didPurge.value = true
     }
-    expect(didPurge).toEventually(beTrue(), timeout: .milliseconds(500))
+    expect(didPurge.value).toEventually(beTrue(), timeout: .milliseconds(500))
   }
 
   static func appendEntrySync(log: PersistentFileLog, entry: String) {
-    var didAppend = false
+    let didAppend = Synchronized(false)
     log.appendEntry(entry: entry) { _ in
-      didAppend = true
+      didAppend.value = true
     }
-    expect(didAppend).toEventually(beTrue(), timeout: .milliseconds(500))
+    expect(didAppend.value).toEventually(beTrue(), timeout: .milliseconds(500))
   }
 }
+
+/// Allows for synchronization pertaining to the file scope.
+private final class Synchronized<T> {
+  private var _storage: T
+  private let lock = NSLock()
+
+  /// Thread safe access here.
+  var value: T {
+    get {
+      return lockAround {
+        _storage
+      }
+    }
+    set {
+      lockAround {
+        _storage = newValue
+      }
+    }
+  }
+
+  init(_ storage: T) {
+    self._storage = storage
+  }
+
+  private func lockAround<U>(_ closure: () -> U) -> U {
+    lock.lock()
+    defer { lock.unlock() }
+    return closure()
+  }
+
+}

packages/expo-updates/CHANGELOG.md

@@ -8,6 +8,8 @@
 
 ### 🐛 Bug fixes
 
+- Fix data race in `AppLauncherWithDatabaseMock.swift`. ([#28924](https://github.com/expo/expo/pull/28924) by [@hakonk](https://github.com/hakonk))
+
 ### 💡 Others
 
 - Removed redundant usage of `EventEmitter` instance. ([#28946](https://github.com/expo/expo/pull/28946) by [@tsapeta](https://github.com/tsapeta))

packages/expo-updates/ios/Tests/AppLauncherWithDatabaseSpec.swift

@@ -94,16 +94,11 @@ class AppLauncherWithDatabaseSpec : ExpoSpec {
           directory: testDatabaseDir,
           completionQueue: DispatchQueue.global(qos: .default)
         )
-        var successValue: Bool? = nil
+        let successValue = Synchronized<Bool?>(nil)
         launcher.launchUpdate(withSelectionPolicy: SelectionPolicyFactory.filterAwarePolicy(withRuntimeVersion: "1")) { error, success in
-          successValue = success
+          successValue.value = success
         }
-
-        while successValue == nil {
-          Thread.sleep(forTimeInterval: 0.1)
-        }
-
-        expect(successValue) == true
+        expect(successValue.value).toEventually(beTrue(), timeout: .milliseconds(10_000))
 
         db.databaseQueue.sync {
           let sameUpdate = try! db.update(withId: testUpdate.updateId, config: config)
@@ -114,3 +109,34 @@ class AppLauncherWithDatabaseSpec : ExpoSpec {
     }
   }
 }
+
+/// Allows for synchronization pertaining to the file scope.
+private final class Synchronized<T> {
+  private var _storage: T
+  private let lock = NSLock()
+
+  /// Thread safe access here.
+  var value: T {
+    get {
+      return lockAround {
+        _storage
+      }
+    }
+    set {
+      lockAround {
+        _storage = newValue
+      }
+    }
+  }
+
+  init(_ storage: T) {
+    self._storage = storage
+  }
+
+  private func lockAround<U>(_ closure: () -> U) -> U {
+    lock.lock()
+    defer { lock.unlock() }
+    return closure()
+  }
+
+}