Ensure Stringable is always available to tests that need it

config.xsd

@@ -96,6 +96,11 @@
         <xs:attribute name="name" type="xs:string" use="required" />
     </xs:complexType>
 
+    <xs:complexType name="StubsAttributeType">
+        <xs:attribute name="name" type="xs:string" use="required" />
+        <xs:attribute name="preloadClasses" type="xs:boolean" default="false" />
+    </xs:complexType>
+
     <xs:complexType name="IgnoreFilesType">
         <xs:choice maxOccurs="unbounded">
             <xs:element name="directory" minOccurs="0" maxOccurs="unbounded" type="NameAttributeType" />
@@ -144,7 +149,7 @@
 
     <xs:complexType name="StubsType">
         <xs:sequence>
-            <xs:element name="file" maxOccurs="unbounded" type="NameAttributeType" />
+            <xs:element name="file" maxOccurs="unbounded" type="StubsAttributeType" />
         </xs:sequence>
     </xs:complexType>
 

src/Psalm/Config.php

@@ -258,6 +258,11 @@ class Config
      */
     private $mock_classes = [];
 
+    /**
+     * @var array<string, string>
+     */
+    private $preloaded_stub_files = [];
+
     /**
      * @var array<string, string>
      */
@@ -1031,7 +1036,17 @@ class Config
                     );
                 }
 
-                $config->addStubFile($file_path);
+                if (isset($stub_file['preloadClasses'])) {
+                    $preload_classes = (string)$stub_file['preloadClasses'];
+
+                    if ($preload_classes === 'true' || $preload_classes === '1') {
+                        $config->addPreloadedStubFile($file_path);
+                    } else {
+                        $config->addStubFile($file_path);
+                    }
+                } else {
+                    $config->addStubFile($file_path);
+                }
             }
         }
 
@@ -1700,6 +1715,56 @@ class Config
         return $this->mock_classes;
     }
 
+    public function visitPreloadedStubFiles(Codebase $codebase, ?Progress $progress = null): void
+    {
+        if ($progress === null) {
+            $progress = new VoidProgress();
+        }
+
+        $core_generic_files = [];
+
+        if (\PHP_VERSION_ID < 80000 && $codebase->php_major_version >= 8) {
+            $stringable_path = dirname(__DIR__, 2) . '/stubs/Stringable.php';
+
+            if (!file_exists($stringable_path)) {
+                throw new \UnexpectedValueException('Cannot locate core generic classes');
+            }
+
+            $core_generic_files[] = $stringable_path;
+        }
+
+        $stub_files = array_merge($core_generic_files, $this->preloaded_stub_files);
+
+        if ($this->load_xdebug_stub) {
+            $xdebug_stub_path = dirname(__DIR__, 2) . '/stubs/Xdebug.php';
+
+            if (!file_exists($xdebug_stub_path)) {
+                throw new \UnexpectedValueException('Cannot locate XDebug stub');
+            }
+
+            $stub_files[] = $xdebug_stub_path;
+        }
+
+        if (!$stub_files) {
+            return;
+        }
+
+        foreach ($stub_files as $file_path) {
+            $file_path = \str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $file_path);
+            $codebase->scanner->addFileToDeepScan($file_path);
+        }
+
+        $progress->debug('Registering preloaded stub files' . "\n");
+
+        $codebase->register_stub_files = true;
+
+        $codebase->scanFiles();
+
+        $codebase->register_stub_files = false;
+
+        $progress->debug('Finished registering preloaded stub files' . "\n");
+    }
+
     public function visitStubFiles(Codebase $codebase, ?Progress $progress = null): void
     {
         if ($progress === null) {
@@ -1741,16 +1806,6 @@ class Config
             $core_generic_files[] = $ext_ds_path;
         }
 
-        if (\version_compare(\PHP_VERSION, '8.0', '<') && $codebase->php_major_version >= 8) {
-            $stringable_path = dirname(__DIR__, 2) . '/stubs/Stringable.php';
-
-            if (!file_exists($stringable_path)) {
-                throw new \UnexpectedValueException('Cannot locate core generic classes');
-            }
-
-            $core_generic_files[] = $stringable_path;
-        }
-
         $stub_files = array_merge($core_generic_files, $this->stub_files);
 
         $phpstorm_meta_path = $this->base_dir . DIRECTORY_SEPARATOR . '.phpstorm.meta.php';
@@ -1769,16 +1824,6 @@ class Config
             }
         }
 
-        if ($this->load_xdebug_stub) {
-            $xdebug_stub_path = dirname(__DIR__, 2) . '/stubs/Xdebug.php';
-
-            if (!file_exists($xdebug_stub_path)) {
-                throw new \UnexpectedValueException('Cannot locate XDebug stub');
-            }
-
-            $stub_files[] = $xdebug_stub_path;
-        }
-
         foreach ($stub_files as $file_path) {
             $file_path = \str_replace(['/', '\\'], DIRECTORY_SEPARATOR, $file_path);
             $codebase->scanner->addFileToDeepScan($file_path);
@@ -2016,6 +2061,11 @@ class Config
         return $this->stub_files;
     }
 
+    public function addPreloadedStubFile(string $stub_file): void
+    {
+        $this->preloaded_stub_files[$stub_file] = $stub_file;
+    }
+
     public function getPhpVersion(): ?string
     {
         if (isset($this->configured_php_version)) {

src/Psalm/Internal/Analyzer/ProjectAnalyzer.php

@@ -582,6 +582,8 @@ class ProjectAnalyzer
 
             $this->config->initializePlugins($this);
 
+            $this->config->visitPreloadedStubFiles($this->codebase, $this->progress);
+
             $this->codebase->scanFiles($this->threads);
 
             $this->codebase->infer_types_from_usage = true;
@@ -604,6 +606,8 @@ class ProjectAnalyzer
 
                     $this->config->initializePlugins($this);
 
+                    $this->config->visitPreloadedStubFiles($this->codebase, $this->progress);
+
                     $this->codebase->scanFiles($this->threads);
                 } else {
                     $diff_no_files = true;
@@ -987,6 +991,8 @@ class ProjectAnalyzer
 
         $this->config->initializePlugins($this);
 
+        $this->config->visitPreloadedStubFiles($this->codebase, $this->progress);
+
         $this->codebase->scanFiles($this->threads);
 
         $this->config->visitStubFiles($this->codebase, $this->progress);
@@ -1120,6 +1126,8 @@ class ProjectAnalyzer
 
         $this->config->initializePlugins($this);
 
+        $this->config->visitPreloadedStubFiles($this->codebase, $this->progress);
+
         $this->codebase->scanFiles($this->threads);
 
         $this->config->visitStubFiles($this->codebase, $this->progress);
@@ -1158,6 +1166,8 @@ class ProjectAnalyzer
 
         $this->config->initializePlugins($this);
 
+        $this->config->visitPreloadedStubFiles($this->codebase, $this->progress);
+
         $this->codebase->scanFiles($this->threads);
 
         $this->config->visitStubFiles($this->codebase, $this->progress);

src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php

@@ -245,7 +245,9 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements FileSour
                     $classlike_storage->class_implements['stringable'] = 'Stringable';
                 }
 
-                $this->codebase->scanner->queueClassLikeForScanning('Stringable');
+                if (\PHP_VERSION_ID >= 80000) {
+                    $this->codebase->scanner->queueClassLikeForScanning('Stringable');
+                }
             }
 
             if (!$this->scan_deep) {

tests/DocumentationTest.php

@@ -171,6 +171,9 @@ class DocumentationTest extends TestCase
         $this->expectException(\Psalm\Exception\CodeException::class);
         $this->expectExceptionMessageRegExp('/\b' . preg_quote($error_message, '/') . '\b/');
 
+        $codebase = $this->project_analyzer->getCodebase();
+        $codebase->config->visitPreloadedStubFiles($codebase);
+
         $file_path = self::$src_dir_path . 'somefile.php';
 
         $this->addFile($file_path, $code);

tests/TestCase.php

@@ -94,6 +94,7 @@ class TestCase extends BaseTestCase
     public function analyzeFile($file_path, \Psalm\Context $context, bool $track_unused_suppressions = true): void
     {
         $codebase = $this->project_analyzer->getCodebase();
+
         $codebase->addFilesToAnalyze([$file_path => $file_path]);
 
         $codebase->scanFiles();

tests/ToStringTest.php

@@ -391,6 +391,9 @@ class ToStringTest extends TestCase
             ],
             'implicitStringableDisallowed' => [
                 '<?php
+                    interface Stringable {
+                        function __toString() {}
+                    }
                     function foo(Stringable $s): void {}
 
                     class Bar {

tests/Traits/InvalidCodeAnalysisTestTrait.php

@@ -84,6 +84,9 @@ trait InvalidCodeAnalysisTestTrait
             $this->expectExceptionMessageRegExp('/\b' . preg_quote($error_message, '/') . '\b/');
         }
 
+        $codebase = $this->project_analyzer->getCodebase();
+        $codebase->config->visitPreloadedStubFiles($codebase);
+
         $this->addFile($file_path, $code);
         $this->analyzeFile($file_path, new Context());
     }

tests/Traits/ValidCodeAnalysisTestTrait.php

@@ -76,6 +76,9 @@ trait ValidCodeAnalysisTestTrait
 
         $this->project_analyzer->setPhpVersion($php_version);
 
+        $codebase = $this->project_analyzer->getCodebase();
+        $codebase->config->visitPreloadedStubFiles($codebase);
+
         $file_path = self::$src_dir_path . 'somefile.php';
 
         $this->addFile($file_path, $code);