Fix various issues with regard to schema conformity when modifying json, fixes #9515

src/Composer/Config/JsonConfigSource.php

@@ -14,6 +14,7 @@ namespace Composer\Config;
 
 use Composer\Json\JsonFile;
 use Composer\Json\JsonManipulator;
+use Composer\Json\JsonValidationException;
 use Composer\Util\Silencer;
 
 /**
@@ -251,14 +252,35 @@ class JsonConfigSource implements ConfigSourceInterface
             $this->arrayUnshiftRef($args, $config);
             call_user_func_array($fallback, $args);
             // avoid ending up with arrays for keys that should be objects
-            foreach (array('require', 'require-dev', 'conflict', 'provide', 'replace', 'suggest', 'config', 'autoload', 'autoload-dev') as $linkType) {
-                if (isset($config[$linkType]) && $config[$linkType] === array()) {
-                    $config[$linkType] = new \stdClass;
+            foreach (array('require', 'require-dev', 'conflict', 'provide', 'replace', 'suggest', 'config', 'autoload', 'autoload-dev', 'scripts', 'scripts-descriptions', 'support', ) as $prop) {
+                if (isset($config[$prop]) && $config[$prop] === array()) {
+                    $config[$prop] = new \stdClass;
+                }
+            }
+            foreach (array('psr-0', 'psr-4') as $prop) {
+                if (isset($config['autoload'][$prop]) && $config['autoload'][$prop] === array()) {
+                    $config['autoload'][$prop] = new \stdClass;
+                }
+                if (isset($config['autoload-dev'][$prop]) && $config['autoload-dev'][$prop] === array()) {
+                    $config['autoload-dev'][$prop] = new \stdClass;
+                }
+            }
+            foreach (array('platform', 'http-basic', 'bearer', 'gitlab-token', 'gitlab-oauth', 'github-oauth', 'preferred-install') as $prop) {
+                if (isset($config['config'][$prop]) && $config['config'][$prop] === array()) {
+                    $config['config'][$prop] = new \stdClass;
                 }
             }
             $this->file->write($config);
         }
 
+        try {
+            $this->file->validateSchema(JsonFile::LAX_SCHEMA);
+        } catch (JsonValidationException $e) {
+            // restore contents to the original state
+            file_put_contents($this->file->getPath(), $contents);
+            throw new \RuntimeException('Failed to update composer.json with a valid format, reverting to the original content. Please report an issue to us with details (command you run and a copy of your composer.json).', 0, $e);
+        }
+
         if ($newFile) {
             Silencer::call('chmod', $this->file->getPath(), 0600);
         }

src/Composer/Json/JsonManipulator.php

@@ -492,7 +492,7 @@ class JsonManipulator
             return $this->removeMainKey($key);
         }
 
-        return false;
+        return true;
     }
 
     public function format($data, $depth = 0)