Merge branch 'feat/app-start-extension-materialize' into feat/app-start-extension-api

# Conflicts:
#	sentry-android-core/src/main/java/io/sentry/android/core/ActivityLifecycleIntegration.java

Author: buenaflor

sentry-android-core/src/main/java/io/sentry/android/core/ActivityLifecycleIntegration.java

@@ -265,10 +265,8 @@ private void startTracing(final @NotNull Activity activity) {
         transactionOptions.setAppStartTransaction(appStartSamplingDecision != null);
         setSpanOrigin(transactionOptions);
 
-        // An extend-app-start transaction (Sentry.extendAppStart) is already open. Reuse its trace
-        // for this ui.load instead of creating a second app.start. It also stores an app-start
-        // trace id, so the headless-start check below is guarded with !extensionActive to avoid
-        // mistaking it for a finished headless start.
+        // Guards the headless-start check below with !extensionActive so the eager extension's
+        // stored trace id isn't mistaken for a finished headless start.
         final boolean extensionActive =
             AppStartMetrics.getInstance().getAppStartExtension().isActive();
 
@@ -279,8 +277,6 @@ private void startTracing(final @NotNull Activity activity) {
 
         final boolean isAppStart =
             !(firstActivityCreated || appStartTime == null || coldStart == null);
-        // Foreground starts create app.start first; ui.load then shares its trace. When the app
-        // start is being extended, the eager app.start txn already exists, so we continue it.
         final boolean createStandaloneAppStart =
             isAppStart
                 && options.isEnableStandaloneAppStartTracing()
@@ -326,9 +322,8 @@ private void startTracing(final @NotNull Activity activity) {
         }
 
         if (extensionActive && isAppStart) {
-          // Attach only the launch activity's screen so a later activity can't overwrite it.
-          // Without
-          // a screen the processor would classify the eager app.start as a headless start.
+          // Only the launch activity sets the screen, so a later activity can't overwrite it. A
+          // screen also keeps the processor from classifying the eager app.start as headless.
           AppStartMetrics.getInstance()
               .getAppStartExtension()
               .setData(APP_START_SCREEN_DATA, activityName);

sentry-android-core/src/main/java/io/sentry/android/core/AppStartExtension.java

@@ -134,10 +134,7 @@ public void finishTransaction(final @NotNull SentryDate endTimestamp) {
     try (final @NotNull ISentryLifecycleToken ignored = lock.acquire()) {
       final @Nullable ITransaction transaction = extendedTransaction;
       if (transaction != null && !transaction.isFinished()) {
-        // If the extended span already finished after endTimestamp, end the transaction there so it
-        // contains the extended span and its duration matches the reported app start vital. When
-        // the
-        // span is still open, waitForChildren keeps the transaction open until it finishes.
+        // End at the extended span's finish if it ran past endTimestamp, so the txn covers it.
         final @Nullable ISpan span = extendedSpan;
         final @Nullable SentryDate spanEnd = span == null ? null : span.getFinishDate();
         final @NotNull SentryDate end =

sentry-android-core/src/main/java/io/sentry/android/core/PerformanceAndroidEventProcessor.java

@@ -106,25 +106,22 @@ public SentryEvent process(@NotNull SentryEvent event, @NotNull Hint hint) {
           final long naturalDurationMs = appStartTimeSpan.getDurationMs();
 
           final long appStartUpDurationMs;
-          // Whether the app start is ready to be finalized (spans attached, marked sent). When not
-          // ready (duration 0 on a non-extended start), we leave it for a later transaction to
-          // retry.
+          // Not ready (duration 0 on a non-extended start) leaves it for a later transaction.
           final boolean appStartReady;
           final @NotNull AppStartExtension extension = appStartMetrics.getAppStartExtension();
           if (extension.isExtended()) {
             final @Nullable SentryDate extendedEnd = extension.getExtendedEndTime();
             if (extendedEnd != null && appStartTimeSpan.hasStarted()) {
-              // The user finished the extension: measure from process start to the extended end,
-              // but never report shorter than the natural first-frame duration.
+              // Measure to the extended end, but never shorter than the natural first-frame
+              // duration.
               final long extendedDurationMs =
                   TimeUnit.NANOSECONDS.toMillis(extendedEnd.nanoTimestamp())
                       - appStartTimeSpan.getStartTimestampMs();
               appStartUpDurationMs = Math.max(naturalDurationMs, extendedDurationMs);
               appStartReady = appStartUpDurationMs != 0;
             } else {
-              // The extension hit the deadline (DEADLINE_EXCEEDED -> null) or there is no valid
-              // start: suppress the measurement so we never emit an artificially inflated value,
-              // but still finalize the app start spans.
+              // Deadline (null) or no valid start: suppress the measurement to avoid an inflated
+              // value, but still finalize the spans.
               appStartUpDurationMs = 0;
               appStartReady = appStartTimeSpan.hasStarted();
             }