Merge pull request #5587 from getsentry/perf/sdk-overhead-reduction-timezone-default

perf(android): [SDK Overhead Reduction 4] Use default timezone directly

Author: adinauer

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## Unreleased
+
+### Internal
+
+- Reduce Android startup overhead by using the default timezone directly on older devices or when no timezone info is available in the locale. ([#5587](https://github.com/getsentry/sentry-java/pull/5587))
+
 ## 8.45.0
 
 ### Features

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

@@ -257,14 +257,19 @@ private void setDeviceIO(
   @SuppressWarnings("NewApi")
   @NotNull
   private TimeZone getTimeZone() {
-    if (buildInfoProvider.getSdkInfoVersion() >= Build.VERSION_CODES.N) {
+    // Only use the costly Calendar API on Android 13+ (API Level 33+) when the locale contains a
+    // Unicode timezone extension (for example "en-US-u-tz-usnyc"), because Calendar honors that
+    // extension. For all other cases, use the process default timezone directly for performance.
+    if (buildInfoProvider.getSdkInfoVersion() >= Build.VERSION_CODES.TIRAMISU) {
       LocaleList locales = context.getResources().getConfiguration().getLocales();
       if (!locales.isEmpty()) {
         Locale locale = locales.get(0);
-        return Calendar.getInstance(locale).getTimeZone();
+        if (locale.getUnicodeLocaleType("tz") != null) {
+          return Calendar.getInstance(locale).getTimeZone();
+        }
       }
     }
-    return Calendar.getInstance().getTimeZone();
+    return TimeZone.getDefault();
   }
 
   @SuppressWarnings("JdkObsolete")

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

@@ -2,16 +2,22 @@ package io.sentry.android.core
 
 import android.content.Context
 import android.content.Intent
+import android.content.res.Configuration
 import android.os.BatteryManager
+import android.os.Build
+import android.os.LocaleList
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import io.sentry.android.core.internal.util.CpuInfoUtils
+import java.util.Locale
+import java.util.TimeZone
 import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 import org.junit.runner.RunWith
+import org.robolectric.annotation.Config
 
 @RunWith(AndroidJUnit4::class)
 class DeviceInfoUtilTest {
@@ -47,6 +53,32 @@ class DeviceInfoUtilTest {
     assertNotNull(deviceInfo.memorySize)
   }
 
+  @Test
+  fun `sets default timezone`() {
+    val deviceInfoUtil = DeviceInfoUtil.getInstance(context, SentryAndroidOptions())
+    val deviceInfo = deviceInfoUtil.collectDeviceInformation(false, false)
+
+    assertEquals(TimeZone.getDefault(), deviceInfo.timezone)
+  }
+
+  @Test
+  @Config(sdk = [Build.VERSION_CODES.TIRAMISU])
+  fun `preserves timezone from locale unicode extension`() {
+    val defaultTimeZone = TimeZone.getDefault()
+    try {
+      TimeZone.setDefault(TimeZone.getTimeZone("UTC"))
+      val configuration = Configuration(context.resources.configuration)
+      configuration.setLocales(LocaleList(Locale.forLanguageTag("en-US-u-tz-usnyc")))
+      val localizedContext = context.createConfigurationContext(configuration)
+      val deviceInfoUtil = DeviceInfoUtil(localizedContext, SentryAndroidOptions())
+      val deviceInfo = deviceInfoUtil.collectDeviceInformation(false, false)
+
+      assertEquals("America/New_York", deviceInfo.timezone?.id)
+    } finally {
+      TimeZone.setDefault(defaultTimeZone)
+    }
+  }
+
   @Test
   fun `does include cpu data`() {
     CpuInfoUtils.getInstance().setCpuMaxFrequencies(listOf(1024))