[Core] Synchronize event bus before use

We can not exclude the possibility that an event is published to the event bus
after test execution has completed. For example because the test framework may
have decided that a test case has timed out and is now terminating test
execution.

As such events from the pending testcase on the synchronized bus may race with
the events from the unsynchronized bus. This in turn may break the `LinkedList`
in the `CanonicalOrderEventPublisher`.

Fixes: #2288 (mabye??)

Author: mpkorstanje

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Removed
 
 ### Fixed
+* [Core] Synchronize event bus before use ([#2358](https://github.com/cucumber/cucumber-jvm/pull/2358)) M.P. Korstanje) 
 
 ## [6.11.0] (2021-08-05)
 

core/src/main/java/io/cucumber/core/runtime/Runtime.java

@@ -31,6 +31,7 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import static io.cucumber.core.runtime.SynchronizedEventBus.synchronize;
 import static java.util.Collections.emptyList;
 import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.toList;
@@ -174,6 +175,9 @@ public Runtime build() {
             }
             final ExitStatus exitStatus = new ExitStatus(runtimeOptions);
             plugins.addPlugin(exitStatus);
+
+            final EventBus eventBus = synchronize(this.eventBus);
+
             if (runtimeOptions.isMultiThreaded()) {
                 plugins.setSerialEventBusOnEventListenerPlugins(eventBus);
             } else {

junit/src/main/java/io/cucumber/junit/Cucumber.java

@@ -21,6 +21,7 @@
 import io.cucumber.core.runtime.ObjectFactoryServiceLoader;
 import io.cucumber.core.runtime.ObjectFactorySupplier;
 import io.cucumber.core.runtime.ScanningTypeRegistryConfigurerSupplier;
+import io.cucumber.core.runtime.SynchronizedEventBus;
 import io.cucumber.core.runtime.ThreadLocalObjectFactorySupplier;
 import io.cucumber.core.runtime.ThreadLocalRunnerSupplier;
 import io.cucumber.core.runtime.TimeServiceEventBus;
@@ -44,6 +45,7 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import static io.cucumber.core.runtime.SynchronizedEventBus.synchronize;
 import static io.cucumber.junit.FileNameCompatibleNames.uniqueSuffix;
 import static java.util.stream.Collectors.groupingBy;
 import static java.util.stream.Collectors.toList;
@@ -148,7 +150,7 @@ public Cucumber(Class<?> clazz) throws InitializationError {
                 .parse(CucumberProperties.fromSystemProperties())
                 .build(junitEnvironmentOptions);
 
-        this.bus = new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID);
+        this.bus = synchronize(new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID));
 
         // Parse the features early. Don't proceed when there are lexer errors
         FeatureParser parser = new FeatureParser(bus::generateId);

testng/src/main/java/io/cucumber/testng/TestNGCucumberRunner.java

@@ -21,6 +21,7 @@
 import io.cucumber.core.runtime.ObjectFactoryServiceLoader;
 import io.cucumber.core.runtime.ObjectFactorySupplier;
 import io.cucumber.core.runtime.ScanningTypeRegistryConfigurerSupplier;
+import io.cucumber.core.runtime.SynchronizedEventBus;
 import io.cucumber.core.runtime.ThreadLocalObjectFactorySupplier;
 import io.cucumber.core.runtime.ThreadLocalRunnerSupplier;
 import io.cucumber.core.runtime.TimeServiceEventBus;
@@ -33,6 +34,7 @@
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 
+import static io.cucumber.core.runtime.SynchronizedEventBus.synchronize;
 import static io.cucumber.testng.TestCaseResultObserver.observe;
 import static java.util.stream.Collectors.toList;
 
@@ -99,7 +101,7 @@ public TestNGCucumberRunner(Class<?> clazz, CucumberPropertiesProvider propertie
                 .enablePublishPlugin()
                 .build(environmentOptions);
 
-        EventBus bus = new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID);
+        EventBus bus = synchronize(new TimeServiceEventBus(Clock.systemUTC(), UUID::randomUUID));
 
         Supplier<ClassLoader> classLoader = ClassLoaders::getDefaultClassLoader;
         FeatureParser parser = new FeatureParser(bus::generateId);