Issue #2958785 by abramm: ContextDefinition isSatisfiedBy() check fails for context using inherited class

core/lib/Drupal/Core/Plugin/Context/ContextDefinition.php

@@ -273,7 +273,7 @@ class ContextDefinition implements ContextDefinitionInterface {
     if ($context->hasContextValue()) {
       $values = [$context->getContextData()];
     }
-    elseif ($definition instanceof static) {
+    elseif ($definition instanceof self) {
       $values = $definition->getSampleValues();
     }
     else {

core/tests/Drupal/Tests/Core/Plugin/Context/ContextDefinitionIsSatisfiedTest.php

@@ -17,6 +17,7 @@ use Drupal\Core\Plugin\Context\Context;
 use Drupal\Core\Plugin\Context\ContextDefinition;
 use Drupal\Core\TypedData\TypedDataManager;
 use Drupal\Core\Validation\ConstraintManager;
+use Drupal\Tests\Core\Plugin\Fixtures\InheritedContextDefinition;
 use Drupal\Tests\UnitTestCase;
 use Prophecy\Argument;
 
@@ -196,6 +197,13 @@ class ContextDefinitionIsSatisfiedTest extends UnitTestCase {
       new ContextDefinition('entity:test_config'),
     ];
 
+    // Inherited context definition class.
+    $data['both any, inherited context requirement definition'] = [
+      TRUE,
+      new InheritedContextDefinition('any'),
+      new ContextDefinition('any'),
+    ];
+
     return $data;
   }
 

core/tests/Drupal/Tests/Core/Plugin/Fixtures/InheritedContextDefinition.php

@@ -0,0 +1,12 @@
+<?php
+
+namespace Drupal\Tests\Core\Plugin\Fixtures;
+
+use Drupal\Core\Plugin\Context\ContextDefinition;
+
+/**
+ * Inherited class used for testing.
+ *
+ * @see \Drupal\Tests\Core\Plugin\Context\ContextDefinitionIsSatisfiedTest
+ */
+class InheritedContextDefinition extends ContextDefinition {}