Filter out app starts with more than 60s

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Fixes
+
+- Filter out app starts with more than 60s ([#2127](https://github.com/getsentry/sentry-java/pull/2127)) 
+
 ## 6.1.3
 
 ### Fixes

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

@@ -13,6 +13,9 @@ public final class AppStartState {
 
   private static @NotNull AppStartState instance = new AppStartState();
 
+  /** We filter out App starts more than 60s */
+  private static final int MAX_APP_START_MILLIS = 60000;
+
   private @Nullable Long appStartMillis;
 
   private @Nullable Long appStartEndMillis;
@@ -48,7 +51,21 @@ public synchronized Long getAppStartInterval() {
     if (appStartMillis == null || appStartEndMillis == null || coldStart == null) {
       return null;
     }
-    return appStartEndMillis - appStartMillis;
+    final long appStart = appStartEndMillis - appStartMillis;
+
+    // We filter out app start more than 60s.
+    // This could be due to many different reasons.
+    // If you do the manual init and init the SDK too late and it does not compute the app start end
+    // in the very first Activity.
+    // If the process starts but the App isn't in the foreground.
+    // If the system forked the zygote earlier to accelerate the app start.
+    // And some unknown reasons that could not be reproduced.
+    // We've seen app starts with hours, days and even months.
+    if (appStart >= MAX_APP_START_MILLIS) {
+      return null;
+    }
+
+    return appStart;
   }
 
   public @Nullable Boolean isColdStart() {

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

@@ -20,7 +20,8 @@
 /**
  * SentryPerformanceProvider is responsible for collecting data (eg appStart) as early as possible
  * as ContentProvider is the only reliable hook for libraries that works across all the supported
- * SDK versions. When minSDK is >= 24, we could use Process.getStartUptimeMillis()
+ * SDK versions. When minSDK is >= 24, we could use Process.getStartUptimeMillis() We could also use
+ * AppComponentFactory but it depends on androidx.core.app.AppComponentFactory
  */
 @ApiStatus.Internal
 public final class SentryPerformanceProvider extends ContentProvider

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

@@ -77,4 +77,16 @@ class AppStartStateTest {
 
         assertEquals(400, sut.appStartInterval)
     }
+
+    @Test
+    fun `getAppStartInterval returns null if more than 60s`() {
+        val sut = AppStartState.getInstance()
+
+        val date = Date()
+        sut.setAppStartTime(100, date)
+        sut.setAppStartEnd(60100)
+        sut.setColdStart(true)
+
+        assertNull(sut.appStartInterval)
+    }
 }