[FrameworkBundle] enable detailed error messages by default when debug enabled

Author: xabbuh

src/Symfony/Bundle/FrameworkBundle/CHANGELOG.md

@@ -10,6 +10,7 @@ CHANGELOG
    invokable Kernel class, and register `FrameworkBundle` by default when the `bundles.php` file is missing
  * [BC BREAK] The `secrets:decrypt-to-local` command terminates with a non-zero exit code when a secret could not be read
  * Deprecate making `cache.app` adapter taggable, use the `cache.app.taggable` adapter instead
+ * Enable `json_decode_detailed_errors` in the default serializer context in debug mode by default when `seld/jsonlint` is installed
 
 7.1
 ---

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -1126,6 +1126,10 @@ private function addSerializerSection(ArrayNodeDefinition $rootNode, callable $e
                             ->prototype('variable')->end()
                         ->end()
                     ->end()
+                    ->validate()
+                        ->ifTrue(fn ($v) => $this->debug && class_exists(JsonParser::class) && !isset($v['default_context'][JsonDecode::DETAILED_ERROR_MESSAGES]))
+                        ->then(function ($v) { $v['default_context'][JsonDecode::DETAILED_ERROR_MESSAGES] = true; return $v; })
+                    ->end()
                 ->end()
             ->end()
         ;

src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/ConfigurationTest.php

@@ -673,6 +673,30 @@ public function testScopedHttpClientsInheritRateLimiterAndRetryFailedConfigurati
         $this->assertSame(999, $scopedClients['qux']['retry_failed']['delay']);
     }
 
+    public function testSerializerJsonDetailedErrorMessagesEnabledByDefaultWithDebugEnabled()
+    {
+        $processor = new Processor();
+        $config = $processor->processConfiguration(new Configuration(true), [
+            [
+                'serializer' => null,
+            ],
+        ]);
+
+        $this->assertSame([JsonDecode::DETAILED_ERROR_MESSAGES => true], $config['serializer']['default_context'] ?? []);
+    }
+
+    public function testSerializerJsonDetailedErrorMessagesNotSetByDefaultWithDebugDisabled()
+    {
+        $processor = new Processor();
+        $config = $processor->processConfiguration(new Configuration(false), [
+            [
+                'serializer' => null,
+            ],
+        ]);
+
+        $this->assertSame([], $config['serializer']['default_context'] ?? []);
+    }
+
     protected static function getBundleDefaultConfig()
     {
         return [