fix(replay): Post checkCanRecord to main thread to prevent deadlock

onScreenshotRecorded can run on the replay executor thread (PixelCopy
masked-capture and emit paths). checkCanRecord -> pauseInternal acquires
lifecycleLock — if another thread holds that lock and submits to the
same single-threaded executor, we deadlock.

When not already on the main thread, post checkCanRecord to the main
looper so it never runs on the executor. On main thread, call directly
to preserve existing synchronous behavior.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: romtsn

CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Fixes
 
+- Fix potential ANR/deadlock in Session Replay when `checkCanRecord` runs on the replay executor thread ([#5837](https://github.com/getsentry/sentry-java/pull/5837))
 - Release `MediaMuxer` when the replay video encoder fails to start to avoid a resource leak ([#5607](https://github.com/getsentry/sentry-java/pull/5607))
 
 ### Performance

sentry-android-replay/src/main/java/io/sentry/android/replay/ReplayIntegration.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import android.os.Build
+import android.os.Looper
 import android.view.MotionEvent
 import io.sentry.Breadcrumb
 import io.sentry.DataCategory.All
@@ -352,7 +353,7 @@ public class ReplayIntegration(
       }
       addFrame(bitmap, frameTimeStamp, screen)
     }
-    checkCanRecord()
+    postOnMainThread { checkCanRecord() }
   }
 
   override fun onScreenshotRecorded(screenshot: File, frameTimestamp: Long) {
@@ -375,7 +376,7 @@ public class ReplayIntegration(
       }
       addFrame(screenshot, frameTimestamp, screen)
     }
-    checkCanRecord()
+    postOnMainThread { checkCanRecord() }
   }
 
   override fun close() {
@@ -444,6 +445,17 @@ public class ReplayIntegration(
     captureStrategy?.onTouchEvent(event)
   }
 
+  // Runs [block] on the main thread. If already there, executes inline; otherwise posts via
+  // the main looper handler. Prevents deadlocks when lifecycle-lock-acquiring code (e.g.
+  // checkCanRecord -> pauseInternal) is called from the replay executor thread.
+  private inline fun postOnMainThread(crossinline block: () -> Unit) {
+    if (Looper.myLooper() == Looper.getMainLooper()) {
+      block()
+    } else {
+      mainLooperHandler.post { block() }
+    }
+  }
+
   /**
    * Check if we're offline or rate-limited and pause for session mode to not overflow the envelope
    * cache.