Add tips to the extends internal class rule errors

Fixes #284

Author: mglaman

src/Rules/Classes/ClassExtendsInternalClassRule.php

@@ -46,30 +46,34 @@ public function processNode(Node $node, Scope $scope): array
 
         // @phpstan-ignore-next-line
         if (!isset($node->namespacedName)) {
-            return $this->buildError(null, $extendedClassName);
+            return [$this->buildError(null, $extendedClassName)->build()];
         }
 
         $currentClassName = $node->namespacedName->toString();
 
         if (!NamespaceCheck::isDrupalNamespace($node)) {
-            return $this->buildError($currentClassName, $extendedClassName);
+            [$this->buildError($currentClassName, $extendedClassName)->build()];
         }
 
         if (NamespaceCheck::isSharedNamespace($node)) {
             return [];
         }
 
-        return $this->buildError($currentClassName, $extendedClassName);
+        $errorBuilder = $this->buildError($currentClassName, $extendedClassName);
+        if ($extendedClassName === 'Drupal\Core\Entity\ContentEntityDeleteForm') {
+            $errorBuilder->tip('Extend \Drupal\Core\Entity\ContentEntityConfirmFormBase. See https://www.drupal.org/node/2491057');
+        } elseif ((string) $node->extends->slice(0, 2) === 'Drupal\Core') {
+            $errorBuilder->tip('Read the Drupal core backwards compatibility and internal API policy: https://www.drupal.org/about/core/policies/core-change-policies/drupal-8-and-9-backwards-compatibility-and-internal-api#internal');
+        }
+        return [$errorBuilder->build()];
     }
 
-    private function buildError(?string $currentClassName, string $extendedClassName): array
+    private function buildError(?string $currentClassName, string $extendedClassName): RuleErrorBuilder
     {
-        return [
-            RuleErrorBuilder::message(\sprintf(
-                '%s extends @internal class %s.',
-                $currentClassName !== null ? \sprintf('Class %s', $currentClassName) : 'Anonymous class',
-                $extendedClassName
-            ))->build()
-        ];
+        return RuleErrorBuilder::message(\sprintf(
+            '%s extends @internal class %s.',
+            $currentClassName !== null ? \sprintf('Class %s', $currentClassName) : 'Anonymous class',
+            $extendedClassName
+        ));
     }
 }

tests/fixtures/drupal/modules/phpstan_fixtures/src/Form/ExtendsContentEntityDeleteForm.php

@@ -0,0 +1,9 @@
+<?php declare(strict_types=1);
+
+namespace Drupal\phpstan_fixtures\Form;
+
+use Drupal\Core\Entity\ContentEntityDeleteForm;
+
+final class ExtendsContentEntityDeleteForm extends ContentEntityDeleteForm {
+
+}

tests/src/Rules/ClassExtendsInternalClassRuleTest.php

@@ -51,7 +51,8 @@ public function pluginData(): \Generator
             [
                 [
                     'Class Drupal\phpstan_fixtures\Internal\ExtendsDrupalCoreInternalClass extends @internal class Drupal\Core\InternalClass.',
-                    7
+                    7,
+                    'Read the Drupal core backwards compatibility and internal API policy: https://www.drupal.org/about/core/policies/core-change-policies/drupal-8-and-9-backwards-compatibility-and-internal-api#internal',
                 ],
             ],
         ];
@@ -60,7 +61,8 @@ public function pluginData(): \Generator
             [
                 [
                     'Class Drupal\phpstan_fixtures\Internal\ExtendsDrupalCorePHPStanDrupalTestsInternalClass extends @internal class Drupal\Core\PHPStanDrupalTests\InternalClass.',
-                    7
+                    7,
+                    'Read the Drupal core backwards compatibility and internal API policy: https://www.drupal.org/about/core/policies/core-change-policies/drupal-8-and-9-backwards-compatibility-and-internal-api#internal',
                 ],
             ],
         ];
@@ -119,6 +121,16 @@ public function pluginData(): \Generator
             __DIR__ . '/../../fixtures/drupal/modules/phpstan_fixtures/src/Internal/ExtendsPHPStanDrupalModuleWithInternalClassesExternalClass.php',
             [],
         ];
+        yield 'tip for ContentEntityDeleteForm' => [
+            __DIR__ . '/../../fixtures/drupal/modules/phpstan_fixtures/src/Form/ExtendsContentEntityDeleteForm.php',
+            [
+                [
+                    'Class Drupal\phpstan_fixtures\Form\ExtendsContentEntityDeleteForm extends @internal class Drupal\Core\Entity\ContentEntityDeleteForm.',
+                    7,
+                    'Extend \Drupal\Core\Entity\ContentEntityConfirmFormBase. See https://www.drupal.org/node/2491057'
+                ]
+            ],
+        ];
     }
 
     private static function cleanDrupalCoreStubs(): void {