fix(android): Read the app start type once per event processor pass

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Prevent duplicated breadcrumbs on tombstone-merged native crash events ([#5888](https://github.com/getsentry/sentry-java/pull/5888))
 - Prevent a class of Session Replay deadlocks by confining lifecycle state changes to Android's main thread ([#5965](https://github.com/getsentry/sentry-java/pull/5965))
 - Symbolicate tombstone native frames for libraries loaded directly from APKs ([#5992](https://github.com/getsentry/sentry-java/pull/5992))
+- Report a consistent app start type across the app start measurement, `contexts.app` and the `app.start` span attributes ([#6006](https://github.com/getsentry/sentry-java/pull/6006))
 
 ### Features
 

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

@@ -86,6 +86,10 @@ public SentryEvent process(@NotNull SentryEvent event, @NotNull Hint hint) {
       }
 
       final @NotNull AppStartMetrics appStartMetrics = AppStartMetrics.getInstance();
+      // The app start type can flip (e.g. the last activity being destroyed marks the next start
+      // as warm) while this runs on the timer thread that finished the transaction. Read it once so
+      // the measurement key, contexts.app and the span attributes below cannot disagree.
+      final @NotNull AppStartMetrics.AppStartType appStartType = appStartMetrics.getAppStartType();
       // the app start measurement is only sent once and only if the transaction has
       // the app.start span, which is automatically created by the SDK.
       if (hasAppStartSpan(transaction)) {
@@ -141,14 +145,14 @@ public SentryEvent process(@NotNull SentryEvent event, @NotNull Hint hint) {
                       (float) appStartUpDurationMs, MeasurementUnit.Duration.MILLISECOND.apiName());
 
               final String appStartKey =
-                  appStartMetrics.getAppStartType() == AppStartMetrics.AppStartType.COLD
+                  appStartType == AppStartMetrics.AppStartType.COLD
                       ? MeasurementValue.KEY_APP_START_COLD
                       : MeasurementValue.KEY_APP_START_WARM;
 
               transaction.getMeasurements().put(appStartKey, value);
             }
 
-            attachAppStartSpans(appStartMetrics, transaction);
+            attachAppStartSpans(appStartMetrics, appStartType, transaction);
             appStartMetrics.onAppStartSpansSent();
           }
         }
@@ -158,14 +162,12 @@ public SentryEvent process(@NotNull SentryEvent event, @NotNull Hint hint) {
           appContext = new App();
           transaction.getContexts().setApp(appContext);
         }
-        final String appStartType =
-            appStartMetrics.getAppStartType() == AppStartMetrics.AppStartType.COLD
-                ? "cold"
-                : "warm";
-        appContext.setStartType(appStartType);
+        final String appStartTypeName =
+            appStartType == AppStartMetrics.AppStartType.COLD ? "cold" : "warm";
+        appContext.setStartType(appStartTypeName);
 
         if (isStandaloneAppStartTxn) {
-          setAppStartVitals(transaction, appStartType);
+          setAppStartVitals(transaction, appStartTypeName);
         }
       }
 
@@ -293,10 +295,12 @@ private boolean hasAppStartSpan(final @NotNull SentryTransaction txn) {
   }
 
   private void attachAppStartSpans(
-      final @NotNull AppStartMetrics appStartMetrics, final @NotNull SentryTransaction txn) {
+      final @NotNull AppStartMetrics appStartMetrics,
+      final @NotNull AppStartMetrics.AppStartType appStartType,
+      final @NotNull SentryTransaction txn) {
 
     // We include process init, content providers and application.onCreate spans only on cold start
-    if (appStartMetrics.getAppStartType() != AppStartMetrics.AppStartType.COLD) {
+    if (appStartType != AppStartMetrics.AppStartType.COLD) {
       return;
     }
 

sentry-android-core/src/main/java/io/sentry/android/core/performance/AppStartMetrics.java

@@ -68,7 +68,9 @@ public enum AppStartType {
   public static final @NotNull AutoClosableReentrantLock staticLock =
       new AutoClosableReentrantLock();
 
-  private @NotNull AppStartType appStartType = AppStartType.UNKNOWN;
+  // Written on the main thread (activity lifecycle, ApplicationStartInfo) and read on whichever
+  // thread finishes an app start transaction, which can be the Sentry timer thread.
+  private volatile @NotNull AppStartType appStartType = AppStartType.UNKNOWN;
   private @Nullable volatile Boolean appLaunchedInForeground;
   private volatile long firstIdle = -1;
 

sentry-android-core/src/test/java/io/sentry/android/core/PerformanceAndroidEventProcessorTest.kt

@@ -205,6 +205,63 @@ class PerformanceAndroidEventProcessorTest {
     }
   }
 
+  @Test
+  fun `cold standalone app start reports the same type on measurement, contexts and spans`() {
+    val sut = fixture.getSut(enablePerformanceV2 = true)
+    AppStartMetrics.getInstance().apply {
+      appStartType = AppStartType.COLD
+      isAppLaunchedInForeground = true
+      classLoadedUptimeMs = 50
+      appStartTimeSpan.apply {
+        setStartedAt(1)
+        setStoppedAt(100)
+      }
+      applicationOnCreateTimeSpan.apply {
+        setStartedAt(10)
+        description = "com.example.App.onCreate"
+        setStoppedAt(42)
+      }
+    }
+
+    var tr = createStandaloneAppStartTransaction(appStartScreen = "Activity")
+    tr = sut.process(tr, Hint())
+
+    assertThat(tr.measurements).containsKey(MeasurementValue.KEY_APP_START_COLD)
+    assertThat(tr.measurements).doesNotContainKey(MeasurementValue.KEY_APP_START_WARM)
+    assertThat(tr.contexts.app!!.startType).isEqualTo("cold")
+    assertThat(tr.contexts.trace!!.data[APP_START_TYPE_DATA]).isEqualTo("cold")
+    // cold starts attach the process init / Application.onCreate breakdown children
+    assertThat(tr.spans).isNotEmpty()
+    for (span in tr.spans) {
+      assertThat(span.data?.get(APP_START_TYPE_DATA)).isEqualTo("cold")
+    }
+  }
+
+  @Test
+  fun `warm standalone app start reports the same type on measurement, contexts and spans`() {
+    val sut = fixture.getSut(enablePerformanceV2 = true)
+    AppStartMetrics.getInstance().apply {
+      appStartType = AppStartType.WARM
+      isAppLaunchedInForeground = true
+      classLoadedUptimeMs = 50
+      appStartTimeSpan.apply {
+        setStartedAt(1)
+        setStoppedAt(100)
+      }
+    }
+
+    var tr = createStandaloneAppStartTransaction(appStartScreen = "Activity")
+    tr = sut.process(tr, Hint())
+
+    assertThat(tr.measurements).containsKey(MeasurementValue.KEY_APP_START_WARM)
+    assertThat(tr.measurements).doesNotContainKey(MeasurementValue.KEY_APP_START_COLD)
+    assertThat(tr.contexts.app!!.startType).isEqualTo("warm")
+    assertThat(tr.contexts.trace!!.data[APP_START_TYPE_DATA]).isEqualTo("warm")
+    for (span in tr.spans) {
+      assertThat(span.data?.get(APP_START_TYPE_DATA)).isEqualTo("warm")
+    }
+  }
+
   @Test
   fun `standalone app start sets screen and type on user spans under the extended span`() {
     val sut = fixture.getSut()