fix(android): Don't swallow interrupts while flushing a startup crash

CHANGELOG.md

@@ -34,6 +34,7 @@
 
 ### Fixes
 
+- Keep the interrupt of the thread that calls `Sentry.init` when it is interrupted while the SDK waits for cached events to be sent after a startup crash ([#6568](https://github.com/getsentry/sentry-java/pull/6568))
 - Capture scroll breadcrumbs for `LazyColumn`, `LazyRow`, lazy grids, and `Pager` on Jetpack Compose foundation 1.10+ ([#6548](https://github.com/getsentry/sentry-java/pull/6548))
 - Prevent the main thread from potentially hanging during app start or when returning to the foreground if Android is slow to register the SDK's network or telephony listeners. `Sentry.init`, Session Replay, and capturing events no longer wait for that registration ([#6537](https://github.com/getsentry/sentry-java/pull/6537))
 - Add opt-in support for matching GraphQL ignored error types against classification specifications via `sentry.graphql.enable-specification-error-type-filtering` ([#6092](https://github.com/getsentry/sentry-java/pull/6092))

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

@@ -157,6 +157,13 @@ private void sendCachedEnvelopes(
           options
               .getLogger()
               .log(SentryLevel.DEBUG, "Synchronous send timed out, continuing in the background.");
+        } catch (InterruptedException e) {
+          // We don't own the calling thread, so keep its interrupt for the code that does
+          Thread.currentThread().interrupt();
+          options
+              .getLogger()
+              .log(
+                  SentryLevel.DEBUG, "Synchronous send interrupted, continuing in the background.");
         }
       }
       options.getLogger().log(SentryLevel.DEBUG, "SendCachedEnvelopeIntegration installed.");

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

@@ -1,5 +1,6 @@
 package io.sentry.android.core
 
+import com.google.common.truth.Truth.assertThat
 import io.sentry.IConnectionStatusProvider
 import io.sentry.IConnectionStatusProvider.ConnectionStatus
 import io.sentry.ILogger
@@ -137,6 +138,27 @@ class SendCachedEnvelopeIntegrationTest {
     verify(fixture.sender).send()
   }
 
+  @Test
+  fun `when interrupted while awaiting the task, keeps the interrupt and continues in the background`() {
+    // the delay keeps the task running, so the wait for it sees the interrupt
+    val sut = fixture.getSut(hasStartupCrashMarker = true, delaySend = 500)
+
+    Thread.currentThread().interrupt()
+    try {
+      sut.register(fixture.scopes, fixture.options)
+
+      assertThat(Thread.currentThread().isInterrupted).isTrue()
+    } finally {
+      // don't leak the interrupt into other tests
+      Thread.interrupted()
+    }
+    verify(fixture.logger)
+      .log(eq(DEBUG), eq("Synchronous send interrupted, continuing in the background."))
+
+    await.untilFalse(fixture.flag)
+    verify(fixture.sender).send()
+  }
+
   @Test
   fun `registers for network connection changes`() {
     val sut =