Merge pull request #1627 from Haehnchen/feature/1624-phpstorm

#1624 secure yaml key class resolving for PhpStorm 2021.3

Author: Haehnchen

src/main/java/fr/adrienbrault/idea/symfony2plugin/util/yaml/YamlHelper.java

@@ -1318,9 +1318,13 @@ public static Collection<PhpClass> getNamespaceResourcesClasses(@NotNull YAMLKey
         if (valueText.endsWith("\\")) {
             Collection<String> resource = YamlHelper.getYamlKeyValueStringOrArray(yamlKeyValue, "resource");
             if (!resource.isEmpty()) {
-                phpClasses.addAll(ServiceContainerUtil.getPhpClassFromResources(
-                    yamlKeyValue.getProject(), valueText, yamlKeyValue.getContainingFile().getVirtualFile(), resource, YamlHelper.getYamlKeyValueStringOrArray(yamlKeyValue, "exclude"))
-                );
+                PsiFile containingFile = yamlKeyValue.getContainingFile();
+                // PhpStorm 2021.1 needs file check
+                if (containingFile != null)  {
+                    phpClasses.addAll(ServiceContainerUtil.getPhpClassFromResources(
+                        yamlKeyValue.getProject(), valueText, containingFile.getVirtualFile(), resource, YamlHelper.getYamlKeyValueStringOrArray(yamlKeyValue, "exclude"))
+                    );
+                }
             }
         }