chore(android): Mark MemoryLimiter sessions as having exited abnormally (JAVA-687)

Mark recovered MemoryLimiter exits as abnormal session endings so release health no longer treats the terminated process as a healthy exit. Reuse the existing AbnormalExit cache repair path with a stable memory_limiter mechanism and the OS exit timestamp.

Author: 0xadam-brown

sentry-android-core/api/sentry-android-core.api

@@ -340,12 +340,14 @@ public final class io/sentry/android/core/MemoryLimiterIntegration : io/sentry/I
 	public fun register (Lio/sentry/IScopes;Lio/sentry/SentryOptions;)V
 }
 
-public final class io/sentry/android/core/MemoryLimiterIntegration$MemoryLimiterHint : io/sentry/hints/BlockingFlushHint, io/sentry/hints/Backfillable {
+public final class io/sentry/android/core/MemoryLimiterIntegration$MemoryLimiterHint : io/sentry/hints/BlockingFlushHint, io/sentry/hints/AbnormalExit, io/sentry/hints/Backfillable {
 	public fun <init> (JLio/sentry/ILogger;JZ)V
+	public fun ignoreCurrentThread ()Z
 	public fun isFlushable (Lio/sentry/protocol/SentryId;)Z
+	public fun mechanism ()Ljava/lang/String;
 	public fun setFlushable (Lio/sentry/protocol/SentryId;)V
 	public fun shouldEnrich ()Z
-	public fun timestamp ()J
+	public fun timestamp ()Ljava/lang/Long;
 }
 
 public final class io/sentry/android/core/NativeEventCollector {

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

@@ -20,6 +20,7 @@
 import io.sentry.SentryOptions;
 import io.sentry.android.core.ApplicationExitInfoHistoryDispatcher.ApplicationExitInfoPolicy;
 import io.sentry.android.core.cache.AndroidEnvelopeCache;
+import io.sentry.hints.AbnormalExit;
 import io.sentry.hints.Backfillable;
 import io.sentry.hints.BlockingFlushHint;
 import io.sentry.protocol.Mechanism;
@@ -71,6 +72,7 @@ public final class MemoryLimiterIntegration implements Integration, Closeable {
   static final @NotNull String MEMORY_LIMITER_DESCRIPTION =
       MEMORY_LIMITER_DESCRIPTION_PREFIX + "AnonSwap";
   static final @NotNull String MEMORY_LIMITER_FINGERPRINT = "memory-limiter";
+  static final @NotNull String MEMORY_LIMITER_MECHANISM = "memory_limiter";
   static final @NotNull String MEMORY_LIMITER_MESSAGE_PREFIX =
       "Android process killed by MemoryLimiter";
 
@@ -368,7 +370,8 @@ public void markReported(final long timestamp) {
    * backfilled with persisted launch state or kept as a lighter historical record.
    */
   @ApiStatus.Internal
-  public static final class MemoryLimiterHint extends BlockingFlushHint implements Backfillable {
+  public static final class MemoryLimiterHint extends BlockingFlushHint
+      implements Backfillable, AbnormalExit {
 
     private final long epochTimestampMs;
     private final boolean shouldEnrich;
@@ -383,11 +386,21 @@ public MemoryLimiterHint(
       this.shouldEnrich = shouldEnrich;
     }
 
-    /** Returns epoch wall-clock time, in milliseconds. */
-    public long timestamp() {
+    @Override
+    public @NotNull Long timestamp() {
       return epochTimestampMs;
     }
 
+    @Override
+    public @NotNull String mechanism() {
+      return MEMORY_LIMITER_MECHANISM;
+    }
+
+    @Override
+    public boolean ignoreCurrentThread() {
+      return true;
+    }
+
     @Override
     public boolean shouldEnrich() {
       return shouldEnrich;

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

@@ -276,7 +276,10 @@ class MemoryLimiterIntegrationTest {
         },
         argThat<Hint> {
           val hint = HintUtils.getSentrySdkHint(this) as MemoryLimiterHint
-          hint.shouldEnrich() && hint.timestamp() == newTimestamp
+          hint.shouldEnrich() &&
+            hint.timestamp() == newTimestamp &&
+            hint.mechanism() == MemoryLimiterIntegration.MEMORY_LIMITER_MECHANISM &&
+            !hint.ignoreCurrentThread()
         },
       )
   }

sentry-android-core/src/test/java/io/sentry/android/core/cache/AndroidEnvelopeCacheTest.kt

@@ -1,9 +1,16 @@
 package io.sentry.android.core.cache
 
+import com.google.common.truth.Truth.assertThat
+import io.sentry.DateUtils
 import io.sentry.ISerializer
 import io.sentry.NoOpLogger
 import io.sentry.SentryEnvelope
+import io.sentry.SentryEvent
 import io.sentry.SentryOptions
+import io.sentry.SentryUUID
+import io.sentry.Session
+import io.sentry.Session.State.Abnormal
+import io.sentry.Session.State.Ok
 import io.sentry.UncaughtExceptionHandlerIntegration.UncaughtExceptionHint
 import io.sentry.android.core.AnrV2Integration.AnrV2Hint
 import io.sentry.android.core.MemoryLimiterIntegration.MemoryLimiterHint
@@ -14,6 +21,7 @@ import io.sentry.transport.ICurrentDateProvider
 import io.sentry.util.HintUtils
 import java.io.File
 import java.lang.IllegalArgumentException
+import java.util.Date
 import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -227,6 +235,51 @@ class AndroidEnvelopeCacheTest {
     assertEquals("23456789", fixture.lastReportedMemoryLimiterFile.readText())
   }
 
+  @Test
+  fun `memory limiter hint marks previous session abnormal at exit timestamp`() {
+    val cache = fixture.getSut(tmpDir)
+    val sessionStart = DateUtils.getCurrentDateTime()
+    val exitTimestamp = sessionStart.time + 1_000
+    val previousSessionFile = EnvelopeCache.getPreviousSessionFile(fixture.options.cacheDirPath!!)
+    fixture.options.serializer.serialize(createSession(sessionStart), previousSessionFile.writer())
+    val envelope = SentryEnvelope.from(fixture.options.serializer, SentryEvent(), null)
+
+    cache.storeEnvelope(
+      envelope,
+      HintUtils.createWithTypeCheckHint(
+        MemoryLimiterHint(0, NoOpLogger.getInstance(), exitTimestamp, true)
+      ),
+    )
+
+    val updatedSession =
+      fixture.options.serializer.deserialize(previousSessionFile.reader(), Session::class.java)!!
+    assertThat(updatedSession.status).isEqualTo(Abnormal)
+    assertThat(updatedSession.timestamp!!.time).isEqualTo(exitTimestamp)
+    assertThat(updatedSession.abnormalMechanism).isEqualTo("memory_limiter")
+  }
+
+  // Protects against misbehaved clocks, stale cached state, or mismatched recovery data.
+  @Test
+  fun `memory limiter exit before previous session start does not mark session abnormal`() {
+    val cache = fixture.getSut(tmpDir)
+    val sessionStart = DateUtils.getCurrentDateTime()
+    val previousSessionFile = EnvelopeCache.getPreviousSessionFile(fixture.options.cacheDirPath!!)
+    fixture.options.serializer.serialize(createSession(sessionStart), previousSessionFile.writer())
+    val envelope = SentryEnvelope.from(fixture.options.serializer, SentryEvent(), null)
+
+    cache.storeEnvelope(
+      envelope,
+      HintUtils.createWithTypeCheckHint(
+        MemoryLimiterHint(0, NoOpLogger.getInstance(), sessionStart.time - 1_000, true)
+      ),
+    )
+
+    val updatedSession =
+      fixture.options.serializer.deserialize(previousSessionFile.reader(), Session::class.java)!!
+    assertThat(updatedSession.status).isEqualTo(Ok)
+    assertThat(updatedSession.abnormalMechanism).isNull()
+  }
+
   @Test
   fun `memory limiter and anr markers are stored independently`() {
     val cache = fixture.getSut(tmpDir)
@@ -260,5 +313,23 @@ class AndroidEnvelopeCacheTest {
     assertFalse(didStore)
   }
 
+  private fun createSession(started: Date): Session =
+    Session(
+      Ok,
+      started,
+      started,
+      0,
+      "distinct-id",
+      SentryUUID.generateSentryId(),
+      true,
+      null,
+      null,
+      null,
+      null,
+      "environment",
+      "release",
+      null,
+    )
+
   internal class UncaughtHint : UncaughtExceptionHint(0, NoOpLogger.getInstance())
 }

sentry/src/main/java/io/sentry/hints/AbnormalExit.java

@@ -5,11 +5,12 @@
 /**
  * Marker interface for Sessions experiencing abnormal status.
  *
- * <p><b>Note:</b> While this interface applies to the broad category of abnormal exits (meaning any
- * exits that weren't classified as normal terminations or crashes) it currently is exclusively used
- * as a hint marker for Android ANRs (both watchdog and ApplicationExitInfo based). If additional
- * categories of abnormal exits were introduced, all instances of discriminator code (`instanceof
- * AbnormalExit`) should be carefully reviewed for ANR specifics accidentally being applied.
+ * <p>This includes exits that were not classified as normal terminations or crashes, such as
+ * Android ANRs and MemoryLimiter process deaths.
+ *
+ * <p><b>Note:</b> Some existing discriminator code (`instanceof AbnormalExit`) is shaped by the
+ * historical ANR-only usage of this interface. New implementations should review all of those call
+ * sites carefully to ensure ANR-specific behavior isn't applied accidentally.
  */
 public interface AbnormalExit {