From cc45d5c82274aebf40818f11088900b8a067f74f Mon Sep 17 00:00:00 2001
From: Markus Hintersteiner <markus.hintersteiner@sentry.io>
Date: Thu, 3 Nov 2022 12:31:19 +0100
Subject: [PATCH] Fix NoSuchElementException in CircularFifoQueue when cloning
 a Scope (#2328)

---
 CHANGELOG.md                                  |  1 +
 sentry/src/main/java/io/sentry/Scope.java     |  2 +-
 .../java/io/sentry/SynchronizedQueue.java     | 14 +++++++++++
 sentry/src/test/java/io/sentry/ScopeTest.kt   | 25 +++++++++++++++++++
 4 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e1f159dc54..d885e51810 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 ### Fixes
 
 - Use correct set-cookie for the HTTP Client response object ([#2326](https://github.com/getsentry/sentry-java/pull/2326))
+- Fix NoSuchElementException in CircularFifoQueue when cloning a Scope ([#2328](https://github.com/getsentry/sentry-java/pull/2328))
 
 ### Features
 
diff --git a/sentry/src/main/java/io/sentry/Scope.java b/sentry/src/main/java/io/sentry/Scope.java
index 16a9f535e2..0d5904fc6a 100644
--- a/sentry/src/main/java/io/sentry/Scope.java
+++ b/sentry/src/main/java/io/sentry/Scope.java
@@ -97,7 +97,7 @@ public Scope(final @NotNull SentryOptions options) {
     this.fingerprint = new ArrayList<>(scope.fingerprint);
     this.eventProcessors = new CopyOnWriteArrayList<>(scope.eventProcessors);
 
-    final Queue<Breadcrumb> breadcrumbsRef = scope.breadcrumbs;
+    final Breadcrumb[] breadcrumbsRef = scope.breadcrumbs.toArray(new Breadcrumb[0]);
 
     Queue<Breadcrumb> breadcrumbsClone = createBreadcrumbsList(scope.options.getMaxBreadcrumbs());
 
diff --git a/sentry/src/main/java/io/sentry/SynchronizedQueue.java b/sentry/src/main/java/io/sentry/SynchronizedQueue.java
index 6236f052df..5e07606cfb 100644
--- a/sentry/src/main/java/io/sentry/SynchronizedQueue.java
+++ b/sentry/src/main/java/io/sentry/SynchronizedQueue.java
@@ -131,4 +131,18 @@ public E remove() {
       return decorated().remove();
     }
   }
+
+  @Override
+  public Object[] toArray() {
+    synchronized (lock) {
+      return decorated().toArray();
+    }
+  }
+
+  @Override
+  public <T> T[] toArray(T[] object) {
+    synchronized (lock) {
+      return decorated().toArray(object);
+    }
+  }
 }
diff --git a/sentry/src/test/java/io/sentry/ScopeTest.kt b/sentry/src/test/java/io/sentry/ScopeTest.kt
index 290aeb02d6..f8fdb5d91d 100644
--- a/sentry/src/test/java/io/sentry/ScopeTest.kt
+++ b/sentry/src/test/java/io/sentry/ScopeTest.kt
@@ -217,6 +217,31 @@ class ScopeTest {
         assertTrue(clone.attachments is CopyOnWriteArrayList)
     }
 
+    @Test
+    fun `copying scope won't crash if there are concurrent operations`() {
+        val options = SentryOptions().apply {
+            maxBreadcrumbs = 10000
+        }
+        val scope = Scope(options)
+        for (i in 0 until options.maxBreadcrumbs) {
+            scope.addBreadcrumb(Breadcrumb.info("item"))
+        }
+
+        // remove one breadcrumb after the other on an extra thread
+        Thread({
+            while (scope.breadcrumbs.isNotEmpty()) {
+                scope.breadcrumbs.remove()
+            }
+        }, "thread-breadcrumb-remover").start()
+
+        // clone in the meantime
+        while (scope.breadcrumbs.isNotEmpty()) {
+            Scope(scope)
+        }
+
+        // expect no exception to be thrown ¯\_(ツ)_/¯
+    }
+
     @Test
     fun `clear scope resets scope to default state`() {
         val scope = Scope(SentryOptions())