feature: allow plugin manager to work without config file (#4639)

src/Psalm/Internal/PluginManager/PluginList.php

@@ -1,6 +1,7 @@
 <?php
 namespace Psalm\Internal\PluginManager;
 
+use RuntimeException;
 use function array_diff_key;
 use function array_flip;
 use function array_key_exists;
@@ -9,7 +10,7 @@ use function strpos;
 
 class PluginList
 {
-    /** @var ConfigFile */
+    /** @var null|ConfigFile */
     private $config_file;
 
     /** @var ComposerLock */
@@ -21,7 +22,7 @@ class PluginList
     /** @var ?array<string,?string> [pluginClass => ?packageName] */
     private $enabled_plugins = null;
 
-    public function __construct(ConfigFile $config_file, ComposerLock $composer_lock)
+    public function __construct(?ConfigFile $config_file, ComposerLock $composer_lock)
     {
         $this->config_file = $config_file;
         $this->composer_lock = $composer_lock;
@@ -34,9 +35,11 @@ class PluginList
     {
         if (!$this->enabled_plugins) {
             $this->enabled_plugins = [];
-            foreach ($this->config_file->getConfig()->getPluginClasses() as $plugin_entry) {
+            if ($this->config_file) {
-                $plugin_class = $plugin_entry['class'];
+                foreach ($this->config_file->getConfig()->getPluginClasses() as $plugin_entry) {
-                $this->enabled_plugins[$plugin_class] = $this->findPluginPackage($plugin_class);
+                    $plugin_class = $plugin_entry['class'];
+                    $this->enabled_plugins[$plugin_class] = $this->findPluginPackage($plugin_class);
+                }
             }
         }
 
@@ -96,11 +99,19 @@ class PluginList
 
     public function enable(string $class): void
     {
+        if (!$this->config_file) {
+            throw new RuntimeException('Cannot find Psalm config');
+        }
+
         $this->config_file->addPlugin($class);
     }
 
     public function disable(string $class): void
     {
+        if (!$this->config_file) {
+            throw new RuntimeException('Cannot find Psalm config');
+        }
+
         $this->config_file->removePlugin($class);
     }
 }

src/Psalm/Internal/PluginManager/PluginListFactory.php

@@ -24,7 +24,11 @@ class PluginListFactory
 
     public function __invoke(string $current_dir, ?string $config_file_path = null): PluginList
     {
-        $config_file = new ConfigFile($current_dir, $config_file_path);
+        try {
+            $config_file = new ConfigFile($current_dir, $config_file_path);
+        } catch (\RuntimeException $exception) {
+            $config_file = null;
+        }
         $composer_lock = new ComposerLock($this->findLockFiles());
 
         return new PluginList($config_file, $composer_lock);

tests/Config/PluginListTest.php

@@ -118,6 +118,23 @@ class PluginListTest extends \Psalm\Tests\TestCase
         $this->assertSame('a\b\c', $plugin_list->resolvePluginClass('vendor/package'));
     }
 
+    /**
+     * @test
+     */
+    public function canShowAvailablePluginsWithoutAConfigFile(): void
+    {
+        $this->composer_lock->getPlugins()->willReturn([
+            'vendor/package' => 'a\b\c',
+            'another-vendor/another-package' => 'c\d\e',
+        ]);
+        $plugin_list = new PluginList(null, $this->composer_lock->reveal());
+
+        $this->assertSame([
+            'a\b\c' => 'vendor/package',
+            'c\d\e' => 'another-vendor/another-package',
+        ], $plugin_list->getAvailable());
+    }
+
     /**
      * @test
      */