RUMM-2606 Make launchTime optional

Sources/Datadog/DatadogCore/Context/LaunchTimePublisher.swift

@@ -13,7 +13,7 @@ import _Datadog_Private
 internal struct LaunchTimePublisher: ContextValuePublisher {
     private typealias AppLaunchHandler = __dd_private_AppLaunchHandler
 
-    let initialValue: LaunchTime
+    let initialValue: LaunchTime?
 
     init() {
         initialValue = LaunchTime(
@@ -23,12 +23,15 @@ internal struct LaunchTimePublisher: ContextValuePublisher {
         )
     }
 
-    func publish(to receiver: @escaping ContextValueReceiver<LaunchTime>) {
+    func publish(to receiver: @escaping ContextValueReceiver<LaunchTime?>) {
+        let launchDate = AppLaunchHandler.shared.launchDate
+        let isActivePrewarm = AppLaunchHandler.shared.isActivePrewarm
+
         AppLaunchHandler.shared.setApplicationDidBecomeActiveCallback { launchTime in
             let value = LaunchTime(
                 launchTime: launchTime,
-                launchDate: initialValue.launchDate,
-                isActivePrewarm: initialValue.isActivePrewarm
+                launchDate: launchDate,
+                isActivePrewarm: isActivePrewarm
             )
             receiver(value)
         }

Sources/Datadog/DatadogInternal/Context/DatadogContext.swift

@@ -61,8 +61,8 @@ public struct DatadogContext {
 
     /// Application launch time.
     ///
-    /// Can be `zero` if the launch could not yet been evaluated.
-    var launchTime: LaunchTime = .zero
+    /// Can be `nil` if the launch could not yet been evaluated.
+    var launchTime: LaunchTime?
 
     /// Provides the history of app foreground / background states.
     var applicationStateHistory: AppStateHistory

Sources/Datadog/DatadogInternal/Context/LaunchTime.swift

@@ -15,15 +15,9 @@ import Foundation
     /// time this value is provided, it will represent the time interval between now and the process start time.
     /* public */ let launchTime: TimeInterval?
 
-    /* public */ let launchDate: Date?
+    /// The date when the application process started.
+    /* public */ let launchDate: Date
 
     /// Returns `true` if the application is pre-warmed.
     /* public */ let isActivePrewarm: Bool
 }
-
-extension LaunchTime {
-    /// Returns a zero launch time with inactive pre-warm.
-    /* public */ static var zero: LaunchTime {
-        .init(launchTime: 0, launchDate: nil, isActivePrewarm: false)
-    }
-}

Sources/Datadog/RUM/RUMMonitor/Scopes/RUMViewScope.swift

@@ -314,21 +314,22 @@ internal class RUMViewScope: RUMScope, RUMContextProvider {
         var attributes = self.attributes
         var loadingTime: Int64? = nil
 
-        if context.launchTime.isActivePrewarm {
+        if context.launchTime?.isActivePrewarm == true {
             // Set `active_pre_warm` attribute to true in case
             // of pre-warmed app.
             attributes[Constants.activePrewarm] = true
-        } else if let launchTime = context.launchTime.launchTime {
+        } else if let launchTime = context.launchTime?.launchTime {
             // Report Application Launch Time only if not pre-warmed
             loadingTime = launchTime.toInt64Nanoseconds
-        } else if let launchDate = context.launchTime.launchDate {
+        } else if let launchDate = context.launchTime?.launchDate {
             // The launchTime can be `nil` if the application is not yet
             // active (UIApplicationDidBecomeActiveNotification). That is
-            // the case when instrumenting a SwiftUI application that starts
-            // a RUM view on `SwiftUI.View.onAppear`.
+            // the case when instrumenting a SwiftUI application that start
+            // a RUM view on `SwiftUI.View/onAppear`.
             //
             // In that case, we consider the time between the application
-            // launch and the view start as the application loading time.
+            // launch and the first view start as the application loading
+            // time.
             loadingTime = viewStartTime.timeIntervalSince(launchDate).toInt64Nanoseconds
         }
 

Tests/DatadogTests/Datadog/DatadogCore/LaunchTimePublisherTests.swift

@@ -21,7 +21,7 @@ class LaunchTimePublisherTests: XCTestCase {
         let launchTime = publisher.initialValue
 
         // Then
-        XCTAssertNotNil(launchTime.launchDate)
+        XCTAssertNotNil(launchTime?.launchDate)
     }
 
     func testThreadSafety() {
@@ -49,7 +49,7 @@ class LaunchTimePublisherTests: XCTestCase {
         let publisher = LaunchTimePublisher()
 
         // Then
-        XCTAssertTrue(publisher.initialValue.isActivePrewarm)
+        XCTAssertTrue(publisher.initialValue?.isActivePrewarm ?? false)
     }
 
     func testIsActivePrewarm_returnsFalse() {
@@ -60,6 +60,6 @@ class LaunchTimePublisherTests: XCTestCase {
         let publisher = LaunchTimePublisher()
 
         // Then
-        XCTAssertFalse(publisher.initialValue.isActivePrewarm)
+        XCTAssertFalse(publisher.initialValue?.isActivePrewarm ?? true)
     }
 }

Tests/DatadogTests/Datadog/RUM/RUMMonitor/Scopes/RUMViewScopeTests.swift

@@ -88,7 +88,11 @@ class RUMViewScopeTests: XCTestCase {
         // Given
         let currentTime: Date = .mockDecember15th2019At10AMUTC()
         var context = self.context
-        context.launchTime = .init(launchTime: 2, launchDate: nil, isActivePrewarm: false)
+        context.launchTime = .init(
+            launchTime: 2,
+            launchDate: .distantPast,
+            isActivePrewarm: false
+        )
 
         let scope = RUMViewScope(
             isInitialView: true,
@@ -196,7 +200,7 @@ class RUMViewScopeTests: XCTestCase {
         var context = self.context
         context.launchTime = .init(
             launchTime: 2,
-            launchDate: nil,
+            launchDate: .distantPast,
             isActivePrewarm: true
         )