Merge pull request #7107 from AndrolGenhald/feature/5482-load-extensions-based-on-composer-config

Enable extensions based on composer.json instead of those loaded at runtime (fixes #5482).

.github/workflows/ci.yml

@@ -82,7 +82,7 @@ jobs:
           ini-values: zend.assertions=1, assert.exception=1
           tools: composer:v2
           coverage: none
-          extensions: decimal
+          extensions: none, curl, dom, filter, json, libxml, mbstring, openssl, pcre, phar, reflection, simplexml, spl, tokenizer, xml, xmlwriter
 
       - uses: actions/checkout@v2
 

.github/workflows/windows-ci.yml

@@ -52,6 +52,7 @@ jobs:
           ini-values: zend.assertions=1, assert.exception=1
           tools: composer:v2
           coverage: none
+          extensions: none, curl, dom, filter, json, libxml, mbstring, openssl, pcre, phar, reflection, simplexml, spl, tokenizer, xml, xmlwriter
 
       - uses: actions/checkout@v2
 

UPGRADING.md

@@ -165,6 +165,7 @@
  - [BC] Property `Psalm\Config::$allow_phpstorm_generics` was removed
  - [BC] Property `Psalm\Config::$exit_functions` was removed
  - [BC] Property `Psalm\Config::$forbid_echo` was removed
+ - [BC] Property `Psalm\Config::$load_xdebug_stub` was removed
  - [BC] Method `Psalm\Type::getEmpty()` was removed
  - [BC] Legacy hook interfaces have been removed:
    -  `Psalm\Plugin\Hook\MethodReturnTypeProviderInterface`

config.xsd

@@ -21,6 +21,8 @@
             <xs:element name="ignoreExceptions" type="ExceptionsType" minOccurs="0" maxOccurs="1" />
             <xs:element name="globals" type="GlobalsType" minOccurs="0" maxOccurs="1" />
             <xs:element name="universalObjectCrates" type="UniversalObjectCratesType" minOccurs="0" maxOccurs="1" />
+            <xs:element name="enableExtensions" type="ExtensionsType" minOccurs="0" maxOccurs="1" />
+            <xs:element name="disableExtensions" type="ExtensionsType" minOccurs="0" maxOccurs="1" />
         </xs:choice>
 
         <xs:attribute name="autoloader" type="xs:string" />
@@ -47,18 +49,6 @@
         <xs:attribute name="ignoreInternalFunctionNullReturn" type="xs:boolean" default="true" />
         <xs:attribute name="includePhpVersionsInErrorBaseline" type="xs:boolean" default="false" />
         <xs:attribute name="inferPropertyTypesFromConstructor" type="xs:boolean" default="true" />
-        <xs:attribute name="loadXdebugStub" type="xs:boolean">
-            <xs:annotation>
-                <xs:documentation xml:lang="en">
-                    Default is runtime-specific: if not present, Psalm will only load the Xdebug stub if psalm has unloaded the extension.
-                </xs:documentation>
-
-                <!-- note: for PHPStorm to mark the attribute as deprecated the doc entry has to be *single line* and start with the word `deprecated` -->
-                <xs:documentation xml:lang="en">
-                    Deprecated. In Psalm 5 extensions will be loaded based on composer.json and overridden with enableExtensions/disableExtensions.
-                </xs:documentation>
-            </xs:annotation>
-        </xs:attribute>
         <xs:attribute name="memoizeMethodCallResults" type="xs:boolean" default="false" />
         <xs:attribute name="rememberPropertyAssignmentsAfterCall" type="xs:boolean" default="true" />
         <xs:attribute name="resolveFromConfigFile" type="xs:boolean" default="true" />
@@ -682,4 +672,29 @@
             <xs:enumeration value="always"/>
         </xs:restriction>
     </xs:simpleType>
+
+    <xs:complexType name="ExtensionsType">
+        <xs:sequence>
+            <xs:element name="extension" maxOccurs="unbounded" type="ExtensionAttributeType" />
+        </xs:sequence>
+    </xs:complexType>
+
+    <xs:simpleType name="ExtensionType">
+        <xs:restriction base="xs:string">
+            <xs:enumeration value="decimal"/>
+            <xs:enumeration value="dom"/>
+            <xs:enumeration value="ds"/>
+            <xs:enumeration value="geos"/>
+            <xs:enumeration value="gmp"/>
+            <xs:enumeration value="mongodb"/>
+            <xs:enumeration value="mysqli"/>
+            <xs:enumeration value="pdo"/>
+            <xs:enumeration value="soap"/>
+            <xs:enumeration value="xdebug"/>
+        </xs:restriction>
+    </xs:simpleType>
+
+    <xs:complexType name="ExtensionAttributeType">
+        <xs:attribute name="name" type="ExtensionType" use="required" />
+    </xs:complexType>
 </xs:schema>

dictionaries/InternalTaintSinkMap.php

@@ -43,9 +43,6 @@ return [
 'mysqli_stmt::prepare' => [['sql']],
 'passthru' => [['shell']],
 'pcntl_exec' => [['shell']],
-'PDO::prepare' => [['sql']],
-'PDO::query' => [['sql']],
-'PDO::exec' => [['sql']],
 'pg_exec' => [[], ['sql']],
 'pg_prepare' => [[], [], ['sql']],
 'pg_put_line' => [[], ['sql']],

docs/running_psalm/configuration.md

@@ -246,16 +246,6 @@ When `true`, Psalm will attempt to find all unused code (including unused variab
 ```
 When `true`, Psalm will report all `@psalm-suppress` annotations that aren't used, the equivalent of running with `--find-unused-psalm-suppress`. Defaults to `false`.
 
-#### loadXdebugStub
-```xml
-<psalm
-  loadXdebugStub="[bool]"
->
-```
-If not present, Psalm will only load the Xdebug stub if Psalm has unloaded the extension.
-When `true`, Psalm will load the Xdebug extension stub (as the extension is unloaded when Psalm runs).
-Setting to `false` prevents the stub from loading.
-
 #### ensureArrayStringOffsetsExist
 ```xml
 <psalm
@@ -336,7 +326,7 @@ When `false`, Psalm will not consider issue at lower level than `errorLevel` as
 #### allowNamedArgumentCalls
 
 ```xml
-<psalm 
+<psalm
   allowNamedArgumentCalls="[bool]"
 >
 ```
@@ -432,6 +422,23 @@ Optional. Same format as `<projectFiles>`. Directories Psalm should load but not
 #### &lt;fileExtensions&gt;
 Optional. A list of extensions to search over. See [Checking non-PHP files](checking_non_php_files.md) to understand how to extend this.
 
+#### &lt;enableExtensions&gt;
+Optional. A list of extensions to enable. By default, only extensions required by your composer.json will be enabled.
+```xml
+<enableExtensions>
+  <extension name="decimal"/>
+  <extension name="pdo"/>
+</enableExtensions>
+```
+
+#### &lt;disableExtensions&gt;
+Optional. A list of extensions to disable. By default, only extensions required by your composer.json will be enabled.
+```xml
+<disableExtensions>
+  <extension name="gmp"/>
+</disableExtensions>
+```
+
 #### &lt;plugins&gt;
 Optional. A list of `<plugin filename="path_to_plugin.php" />` entries. See the [Plugins](plugins/using_plugins.md) section for more information.
 
@@ -483,7 +490,7 @@ The  following configuration declares custom types for super-globals (`$GLOBALS`
 ```xml
 <globals>
   <var name="$GLOBALS" type="array{DB: MyVendor\DatabaseConnection, VIEW: MyVendor\TemplateView}" />
-  <var name="$_GET" type="array{data: array<string, string>}" />     
+  <var name="$_GET" type="array{data: array<string, string>}" />
 </globals>
 ```
 

psalm-baseline.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<files psalm-version="dev-master@c90cffd382bb7a5d390387d4ad2a02a4935fba5c">
+<files psalm-version="dev-master@093edcbe1d5c90ad574efcddd62fe741819e7cf2">
   <file src="examples/TemplateChecker.php">
     <PossiblyUndefinedIntArrayOffset occurrences="2">
       <code>$comment_block-&gt;tags['variablesfrom'][0]</code>
@@ -24,9 +24,6 @@
       <code>getAdditionalFileTypeAnalyzers</code>
       <code>getAdditionalFileTypeScanners</code>
     </DeprecatedMethod>
-    <DeprecatedProperty occurrences="1">
-      <code>$this-&gt;load_xdebug_stub</code>
-    </DeprecatedProperty>
   </file>
   <file src="src/Psalm/Config/FileFilter.php">
     <PossiblyUndefinedIntArrayOffset occurrences="1">
@@ -203,12 +200,6 @@
       <code>$stmt-&gt;expr-&gt;getArgs()[0]</code>
     </PossiblyUndefinedIntArrayOffset>
   </file>
-  <file src="src/Psalm/Internal/Cli/Psalm.php">
-    <DeprecatedProperty occurrences="2">
-      <code>$config-&gt;load_xdebug_stub</code>
-      <code>$config-&gt;load_xdebug_stub</code>
-    </DeprecatedProperty>
-  </file>
   <file src="src/Psalm/Internal/Codebase/InternalCallMapHandler.php">
     <PossiblyUndefinedIntArrayOffset occurrences="2">
       <code>$callables[0]</code>
@@ -286,8 +277,7 @@
     <DeprecatedProperty occurrences="1">
       <code>$storage-&gt;template_extended_count</code>
     </DeprecatedProperty>
-    <PossiblyUndefinedIntArrayOffset occurrences="4">
+    <PossiblyUndefinedIntArrayOffset occurrences="3">
-      <code>$imported_type_data[3]</code>
       <code>$l[4]</code>
       <code>$r[4]</code>
       <code>$var_line_parts[0]</code>

src/Psalm/Config.php

@@ -46,6 +46,7 @@ use UnexpectedValueException;
 use XdgBaseDir\Xdg;
 use stdClass;
 
+use function array_key_exists;
 use function array_map;
 use function array_merge;
 use function array_pad;
@@ -58,7 +59,6 @@ use function class_exists;
 use function count;
 use function dirname;
 use function explode;
-use function extension_loaded;
 use function file_exists;
 use function file_get_contents;
 use function filetype;
@@ -196,15 +196,6 @@ class Config
      */
     public $throw_exception = false;
 
-    /**
-     * Whether or not to load Xdebug stub
-     *
-     * @deprecated going to be removed in Psalm 5
-     *
-     * @var bool|null
-     */
-    public $load_xdebug_stub;
-
     /**
      * The directory to store PHP Parser (and other) caches
      *
@@ -574,6 +565,34 @@ class Config
     /** @var ?int */
     public $threads;
 
+    /**
+     * @psalm-readonly-allow-private-mutation
+     * @var array{
+     *     decimal: bool,
+     *     dom: bool,
+     *     ds: bool,
+     *     geos: bool,
+     *     gmp: bool,
+     *     mongodb: bool,
+     *     mysqli: bool,
+     *     pdo: bool,
+     *     soap: bool,
+     *     xdebug: bool,
+     * }
+     */
+    public $php_extensions = [
+        "decimal" => false,
+        "dom" => false,
+        "ds" => false,
+        "geos" => false,
+        "gmp" => false,
+        "mongodb" => false,
+        "mysqli" => false,
+        "pdo" => false,
+        "soap" => false,
+        "xdebug" => false,
+    ];
+
     protected function __construct()
     {
         self::$instance = $this;
@@ -931,7 +950,6 @@ class Config
             'ignoreInternalFunctionFalseReturn' => 'ignore_internal_falsable_issues',
             'ignoreInternalFunctionNullReturn' => 'ignore_internal_nullable_issues',
             'includePhpVersionsInErrorBaseline' => 'include_php_versions_in_error_baseline',
-            'loadXdebugStub' => 'load_xdebug_stub',
             'ensureArrayStringOffsetsExist' => 'ensure_array_string_offsets_exist',
             'ensureArrayIntOffsetsExist' => 'ensure_array_int_offsets_exist',
             'reportMixedIssues' => 'show_mixed_issues',
@@ -966,6 +984,36 @@ class Config
             $base_dir = $current_dir;
         }
 
+        $composer_json_path = Composer::getJsonFilePath($config->base_dir);
+
+        $composer_json = null;
+        if (file_exists($composer_json_path)) {
+            if (!$composer_json = json_decode(file_get_contents($composer_json_path), true)) {
+                throw new UnexpectedValueException('Invalid composer.json at ' . $composer_json_path);
+            }
+        }
+        foreach ($config->php_extensions as $ext => $_) {
+            $config->php_extensions[$ext] = isset($composer_json["require"]["ext-$ext"]);
+        }
+
+        if (isset($config_xml->enableExtensions) && isset($config_xml->enableExtensions->extension)) {
+            foreach ($config_xml->enableExtensions->extension as $extension) {
+                assert(isset($extension["name"]));
+                $extensionName = (string) $extension["name"];
+                assert(array_key_exists($extensionName, $config->php_extensions));
+                $config->php_extensions[$extensionName] = true;
+            }
+        }
+
+        if (isset($config_xml->disableExtensions) && isset($config_xml->disableExtensions->extension)) {
+            foreach ($config_xml->disableExtensions->extension as $extension) {
+                assert(isset($extension["name"]));
+                $extensionName = (string) $extension["name"];
+                assert(array_key_exists($extensionName, $config->php_extensions));
+                $config->php_extensions[$extensionName] = false;
+            }
+        }
+
         if (isset($config_xml['phpVersion'])) {
             $config->configured_php_version = (string) $config_xml['phpVersion'];
         }
@@ -1969,7 +2017,6 @@ class Config
             $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'CoreGenericClasses.phpstub',
             $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'CoreGenericIterators.phpstub',
             $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'CoreImmutableClasses.phpstub',
-            $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'DOM.phpstub',
             $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'Reflection.phpstub',
             $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'SPL.phpstub',
         ];
@@ -1984,39 +2031,11 @@ class Config
             $this->internal_stubs[] = $stringable_path;
         }
 
-        if (extension_loaded('PDO')) {
+        foreach ($this->php_extensions as $ext => $enabled) {
-            $ext_pdo_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'pdo.phpstub';
+            if ($enabled) {
-            $this->internal_stubs[] = $ext_pdo_path;
+                $this->internal_stubs[] = $dir_lvl_2 . DIRECTORY_SEPARATOR . "stubs"
-        }
+                    . DIRECTORY_SEPARATOR . "extensions" . DIRECTORY_SEPARATOR . "$ext.phpstub";
-
+            }
-        if (extension_loaded('soap')) {
-            $ext_soap_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'soap.phpstub';
-            $this->internal_stubs[] = $ext_soap_path;
-        }
-
-        if (extension_loaded('ds')) {
-            $ext_ds_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'ext-ds.phpstub';
-            $this->internal_stubs[] = $ext_ds_path;
-        }
-
-        if (extension_loaded('mongodb')) {
-            $ext_mongodb_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'mongodb.phpstub';
-            $this->internal_stubs[] = $ext_mongodb_path;
-        }
-
-        if ($this->load_xdebug_stub) {
-            $xdebug_stub_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'Xdebug.phpstub';
-            $this->internal_stubs[] = $xdebug_stub_path;
-        }
-
-        if (extension_loaded('mysqli')) {
-            $ext_mysqli_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'mysqli.phpstub';
-            $this->internal_stubs[] = $ext_mysqli_path;
-        }
-
-        if (extension_loaded('decimal')) {
-            $ext_decimal_path = $dir_lvl_2 . DIRECTORY_SEPARATOR . 'stubs' . DIRECTORY_SEPARATOR . 'decimal.phpstub';
-            $this->internal_stubs[] = $ext_decimal_path;
         }
 
         foreach ($this->internal_stubs as $stub_path) {

src/Psalm/Internal/Cli/Psalm.php

@@ -253,7 +253,7 @@ final class Psalm
 
         self::emitMacPcreWarning($options, $threads);
 
-        self::restart($options, $config, $threads);
+        self::restart($options, $threads);
 
         if (isset($options['debug-emitted-issues'])) {
             $config->debug_emitted_issues = true;
@@ -882,7 +882,7 @@ final class Psalm
         }
     }
 
-    private static function restart(array $options, Config $config, int $threads): void
+    private static function restart(array $options, int $threads): void
     {
         $ini_handler = new PsalmRestarter('PSALM');
 
@@ -907,10 +907,6 @@ final class Psalm
 
         // If Xdebug is enabled, restart without it
         $ini_handler->check();
-
-        if ($config->load_xdebug_stub === null && PsalmRestarter::getSkippedVersion() !== '') {
-            $config->load_xdebug_stub = true;
-        }
     }
 
     private static function detectThreads(array $options, Config $config, bool $in_ci): int

src/Psalm/Internal/Provider/ReturnTypeProvider/PdoStatementReturnTypeProvider.php

@@ -2,7 +2,7 @@
 
 namespace Psalm\Internal\Provider\ReturnTypeProvider;
 
-use PDO;
+use Psalm\Config;
 use Psalm\Plugin\EventHandler\Event\MethodReturnTypeProviderEvent;
 use Psalm\Plugin\EventHandler\MethodReturnTypeProviderInterface;
 use Psalm\Type;
@@ -15,8 +15,6 @@ use Psalm\Type\Atomic\TObject;
 use Psalm\Type\Atomic\TScalar;
 use Psalm\Type\Union;
 
-use function class_exists;
-
 /**
  * @internal
  */
@@ -29,11 +27,12 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
 
     public static function getMethodReturnType(MethodReturnTypeProviderEvent $event): ?Union
     {
+        $config = Config::getInstance();
         $source = $event->getSource();
         $call_args = $event->getCallArgs();
         $method_name_lowercase = $event->getMethodNameLowercase();
         if ($method_name_lowercase === 'fetch'
-            && class_exists('PDO')
+            && $config->php_extensions["pdo"]
             && isset($call_args[0])
             && ($first_arg_type = $source->getNodeTypeProvider()->getType($call_args[0]->value))
             && $first_arg_type->isSingleIntLiteral()
@@ -41,7 +40,7 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
             $fetch_mode = $first_arg_type->getSingleIntLiteral()->value;
 
             switch ($fetch_mode) {
-                case PDO::FETCH_ASSOC: // array<string,scalar|null>|false
+                case 2: // PDO::FETCH_ASSOC - array<string,scalar|null>|false
                     return new Union([
                         new TArray([
                             Type::getString(),
@@ -53,7 +52,7 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
                         new TFalse(),
                     ]);
 
-                case PDO::FETCH_BOTH: // array<array-key,scalar|null>|false
+                case 4: // PDO::FETCH_BOTH - array<array-key,scalar|null>|false
                     return new Union([
                         new TArray([
                             Type::getArrayKey(),
@@ -65,16 +64,16 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
                         new TFalse(),
                     ]);
 
-                case PDO::FETCH_BOUND: // bool
+                case 6: // PDO::FETCH_BOUND - bool
                     return Type::getBool();
 
-                case PDO::FETCH_CLASS: // object|false
+                case 8: // PDO::FETCH_CLASS - object|false
                     return new Union([
                         new TObject(),
                         new TFalse(),
                     ]);
 
-                case PDO::FETCH_LAZY: // object|false
+                case 1: // PDO::FETCH_LAZY - object|false
                     // This actually returns a PDORow object, but that class is
                     // undocumented, and its attributes are all dynamic anyway
                     return new Union([
@@ -82,7 +81,7 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
                         new TFalse(),
                     ]);
 
-                case PDO::FETCH_NAMED: // array<string, scalar|list<scalar>>|false
+                case 11: // PDO::FETCH_NAMED - array<string, scalar|list<scalar>>|false
                     return new Union([
                         new TArray([
                             Type::getString(),
@@ -94,7 +93,7 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
                         new TFalse(),
                     ]);
 
-                case PDO::FETCH_NUM: // list<scalar|null>|false
+                case 3: // PDO::FETCH_NUM - list<scalar|null>|false
                     return new Union([
                         new TList(
                             new Union([
@@ -105,7 +104,7 @@ class PdoStatementReturnTypeProvider implements MethodReturnTypeProviderInterfac
                         new TFalse(),
                     ]);
 
-                case PDO::FETCH_OBJ: // stdClass|false
+                case 5: // PDO::FETCH_OBJ - stdClass|false
                     return new Union([
                         new TNamedObject('stdClass'),
                         new TFalse(),

src/Psalm/Internal/Provider/ReturnTypeProvider/PdoStatementSetFetchMode.php

@@ -2,7 +2,6 @@
 
 namespace Psalm\Internal\Provider\ReturnTypeProvider;
 
-use PDO;
 use Psalm\Internal\Analyzer\Statements\ExpressionAnalyzer;
 use Psalm\Internal\Analyzer\StatementsAnalyzer;
 use Psalm\Plugin\EventHandler\Event\MethodParamsProviderEvent;
@@ -62,7 +61,7 @@ class PdoStatementSetFetchMode implements MethodParamsProviderInterface
                 $value = $first_call_arg_type->getSingleIntLiteral()->value;
 
                 switch ($value) {
-                    case PDO::FETCH_COLUMN:
+                    case 7: // PDO::FETCH_COLUMN
                         $params[] = new FunctionLikeParameter(
                             'colno',
                             false,
@@ -73,7 +72,7 @@ class PdoStatementSetFetchMode implements MethodParamsProviderInterface
                         );
                         break;
 
-                    case PDO::FETCH_CLASS:
+                    case 8: // PDO::FETCH_CLASS
                         $params[] = new FunctionLikeParameter(
                             'classname',
                             false,
@@ -93,7 +92,7 @@ class PdoStatementSetFetchMode implements MethodParamsProviderInterface
                         );
                         break;
 
-                    case PDO::FETCH_INTO:
+                    case 9: // PDO::FETCH_INTO
                         $params[] = new FunctionLikeParameter(
                             'object',
                             false,

stubs/extensions/gmp.phpstub

@@ -0,0 +1,11 @@
+<?php
+
+class GMP implements Serializable {
+    private function __construct() {}
+
+    public function __toString(): string {}
+
+    public function serialize(): string {}
+
+    public function unserialize(string $data): void {}
+}

stubs/extensions/pdo.phpstub

@@ -0,0 +1,158 @@
+<?php
+
+class PDO
+{
+    public const PARAM_NULL = 0;
+    public const PARAM_INT = 1;
+    public const PARAM_STR = 2;
+    public const PARAM_LOB = 3;
+    public const PARAM_STMT = 4;
+    public const PARAM_BOOL = 5;
+    // public const PARAM_STR_NATL = 1073741824; since 7.2
+    // public const PARAM_STR_CHAR = 536870912; since 7.2
+    public const PARAM_INPUT_OUTPUT = 2147483648;
+    // public const FETCH_DEFAULT = 0; since 8.0.7
+    public const FETCH_LAZY = 1;
+    public const FETCH_ASSOC = 2;
+    public const FETCH_NAMED = 11;
+    public const FETCH_NUM = 3;
+    public const FETCH_BOTH = 4;
+    public const FETCH_OBJ = 5;
+    public const FETCH_BOUND = 6;
+    public const FETCH_COLUMN = 7;
+    public const FETCH_CLASS = 8;
+    public const FETCH_INTO = 9;
+    public const FETCH_FUNC = 10;
+    public const FETCH_GROUP = 65536;
+    public const FETCH_UNIQUE = 196608;
+    public const FETCH_KEY_PAIR = 12;
+    public const FETCH_CLASSTYPE = 262144;
+    public const FETCH_SERIALIZE = 524288; // Deprecated 8.1
+    public const FETCH_PROPS_LATE = 1048576;
+    public const ATTR_AUTOCOMMIT = 0;
+    public const ATTR_PREFETCH = 1;
+    public const ATTR_TIMEOUT = 2;
+    public const ATTR_ERRMODE = 3;
+    public const ATTR_SERVER_VERSION = 4;
+    public const ATTR_CLIENT_VERSION = 5;
+    public const ATTR_SERVER_INFO = 6;
+    public const ATTR_CONNECTION_STATUS = 7;
+    public const ATTR_CASE = 8;
+    public const ATTR_CURSOR_NAME = 9;
+    public const ATTR_CURSOR = 10;
+    public const ATTR_DRIVER_NAME = 16;
+    public const ATTR_ORACLE_NULLS = 11;
+    public const ATTR_PERSISTENT = 12;
+    public const ATTR_STATEMENT_CLASS = 13;
+    public const ATTR_FETCH_CATALOG_NAMES = 15;
+    public const ATTR_FETCH_TABLE_NAMES = 14;
+    public const ATTR_STRINGIFY_FETCHES = 17;
+    public const ATTR_MAX_COLUMN_LEN = 18;
+    public const ATTR_DEFAULT_FETCH_MODE = 19;
+    public const ATTR_EMULATE_PREPARES = 20;
+    // public const ATTR_DEFAULT_STR_PARAM = 21; since 7.2
+    public const ERRMODE_SILENT = 0;
+    public const ERRMODE_WARNING = 1;
+    public const ERRMODE_EXCEPTION = 2;
+    public const CASE_NATURAL = 0;
+    public const CASE_LOWER = 2;
+    public const CASE_UPPER = 1;
+    public const NULL_NATURAL = 0;
+    public const NULL_EMPTY_STRING = 1;
+    public const NULL_TO_STRING = 2;
+    public const FETCH_ORI_NEXT = 0;
+    public const FETCH_ORI_PRIOR = 1;
+    public const FETCH_ORI_FIRST = 2;
+    public const FETCH_ORI_LAST = 3;
+    public const FETCH_ORI_ABS = 4;
+    public const FETCH_ORI_REL = 5;
+    public const CURSOR_FWDONLY = 0;
+    public const CURSOR_SCROLL = 1;
+    public const ERR_NONE = 00000;
+    public const PARAM_EVT_ALLOC = 0;
+    public const PARAM_EVT_FREE = 1;
+    public const PARAM_EVT_EXEC_PRE = 2;
+    public const PARAM_EVT_EXEC_POST = 3;
+    public const PARAM_EVT_FETCH_PRE = 4;
+    public const PARAM_EVT_FETCH_POST = 5;
+    public const PARAM_EVT_NORMALIZE = 6;
+    // public const SQLITE_DETERMINISTIC = ???; since 7.1.4 with pdo_sqlite
+
+    public function __construct(
+        string $dsn,
+        ?string $username = null,
+        ?string $password = null,
+        ?array $options = null
+    ) {}
+
+    public function beginTransaction(): bool {}
+
+    public function commit(): bool {}
+
+    public function errorCode(): ?string {}
+
+    public function errorInfo(): array {}
+
+    /**
+     * @psalm-taint-sink sql $statement
+     *
+     * @return int|false
+     */
+    public function exec(string $statement) {}
+
+    /** @return bool|int|string|array|null */
+    public function getAttribute(int $attribute) {}
+
+    public static function getAvailableDrivers(): array {}
+
+    public function inTransaction(): bool {}
+
+    /** @return string|false */
+    public function lastInsertId(?string $name = null) {}
+
+    /**
+     * @psalm-taint-sink sql $query
+     *
+     * @return PDOStatement|false
+     */
+    public function prepare(string $query, array $options = []) {}
+
+    /**
+     * @psalm-taint-sink sql $query
+     *
+     * @return PDOStatement|false
+     */
+    public function query(string $query, ?int $fetchMode = null) {}
+
+    /**
+     * @return string|false
+     */
+    public function quote(string $string, int $type = PDO::PARAM_STR) {}
+
+    public function rollBack(): bool {}
+
+    public function setAttribute(int $attribute, mixed $value): bool {}
+}
+
+/**
+ * @template TValue
+ *
+ * @template-implements Traversable<int, TValue>
+ */
+class PDOStatement implements Traversable
+{
+    /**
+     * @psalm-taint-sink callable $class
+     *
+     * @template T of object
+     * @param class-string<T> $class
+     * @param array $ctorArgs
+     * @return false|T
+     */
+    public function fetchObject($class = \stdclass::class, array $ctorArgs = array()) {}
+}
+
+ class PDOException extends RuntimeException {
+    protected string $code;
+    public ?array $errorInfo = null;
+}

stubs/extensions/soap.phpstub

@@ -282,3 +282,30 @@ class SoapClient  {
      public function __setSoapHeaders ($soapheaders = null) {}
 
 }
+
+class SoapFault extends Exception {
+    /**
+     * @param array|string|null $code
+     */
+    public function __construct(
+        $code,
+        string $string,
+        ?string $actor = null,
+        mixed $details = null,
+        ?string $name = null,
+        mixed $headerFault = null
+    ) {}
+}
+
+class SoapHeader {
+    public function __construct(
+        string $namespace,
+        string $name,
+        // Actually doesn't have a default, not specifying results in no SoapHeader::$data property. Specifying null
+        // results in a SoapHeader::$data property with null as the value. This probably makes no difference.
+        mixed $data = null,
+        bool $mustUnderstand = false,
+        // Same as $data, no default. The documentation specifies this as a `string` but it accepts null.
+        ?string $actor = null
+    ) {}
+}

stubs/pdo.phpstub

@@ -1,19 +0,0 @@
-<?php
-
-/**
- * @template TValue
- *
- * @template-implements Traversable<int, TValue>
- */
-class PDOStatement implements Traversable
-{
-    /**
-     * @psalm-taint-sink callable $class
-     *
-     * @template T of object
-     * @param class-string<T> $class
-     * @param array $ctorArgs
-     * @return false|T
-     */
-    public function fetchObject($class = \stdclass::class, array $ctorArgs = array()) {}
-}

tests/BinaryOperationTest.php

@@ -8,8 +8,6 @@ use Psalm\Exception\CodeException;
 use Psalm\Tests\Traits\InvalidCodeAnalysisTestTrait;
 use Psalm\Tests\Traits\ValidCodeAnalysisTestTrait;
 
-use function class_exists;
-
 use const DIRECTORY_SEPARATOR;
 
 class BinaryOperationTest extends TestCase
@@ -19,10 +17,6 @@ class BinaryOperationTest extends TestCase
 
     public function testGMPOperations(): void
     {
-        if (class_exists('GMP') === false) {
-            $this->markTestSkipped('Cannot run test, base class "GMP" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php
@@ -88,10 +82,6 @@ class BinaryOperationTest extends TestCase
 
     public function testDecimalOperations(): void
     {
-        if (!class_exists('Decimal\\Decimal')) {
-            $this->markTestSkipped('Cannot run test, base class "Decimal\\Decimal" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php

tests/ClassTest.php

@@ -5,8 +5,6 @@ namespace Psalm\Tests;
 use Psalm\Tests\Traits\InvalidCodeAnalysisTestTrait;
 use Psalm\Tests\Traits\ValidCodeAnalysisTestTrait;
 
-use function class_exists;
-
 class ClassTest extends TestCase
 {
     use InvalidCodeAnalysisTestTrait;
@@ -14,10 +12,6 @@ class ClassTest extends TestCase
 
     public function testExtendsMysqli(): void
     {
-        if (class_exists('mysqli') === false) {
-            $this->markTestSkipped('Cannot run test, base class "mysqli" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php

tests/Config/ConfigFileTest.php

@@ -3,6 +3,7 @@
 namespace Psalm\Tests\Config;
 
 use Psalm\Config;
+use Psalm\Exception\ConfigException;
 use Psalm\Internal\PluginManager\ConfigFile;
 use Psalm\Internal\RuntimeCaches;
 use Psalm\Tests\TestCase;
@@ -206,6 +207,64 @@ class ConfigFileTest extends TestCase
         );
     }
 
+    public function testEnableExtensions(): void
+    {
+        file_put_contents($this->file_path, trim('
+            <?xml version="1.0"?>
+            <psalm>
+                <enableExtensions>
+                    <extension name="mysqli"/>
+                    <extension name="pdo"/>
+                </enableExtensions>
+            </psalm>
+        '));
+
+        $config_file = new ConfigFile((string)getcwd(), $this->file_path);
+        $config = $config_file->getConfig();
+
+        $this->assertTrue($config->php_extensions["mysqli"]);
+        $this->assertTrue($config->php_extensions["pdo"]);
+    }
+
+    public function testDisableExtensions(): void
+    {
+        file_put_contents($this->file_path, trim('
+            <?xml version="1.0"?>
+            <psalm>
+                <enableExtensions>
+                    <extension name="mysqli"/>
+                    <extension name="pdo"/>
+                </enableExtensions>
+                <disableExtensions>
+                    <extension name="mysqli"/>
+                    <extension name="pdo"/>
+                </disableExtensions>
+            </psalm>
+        '));
+
+        $config_file = new ConfigFile((string)getcwd(), $this->file_path);
+        $config = $config_file->getConfig();
+
+        $this->assertFalse($config->php_extensions["mysqli"]);
+        $this->assertFalse($config->php_extensions["pdo"]);
+    }
+
+    public function testInvalidExtension(): void
+    {
+        $this->expectException(ConfigException::class);
+
+        file_put_contents($this->file_path, trim('
+            <?xml version="1.0"?>
+            <psalm>
+                <enableExtensions>
+                    <extension name="NotARealExtension"/>
+                </enableExtensions>
+            </psalm>
+        '));
+
+        (new ConfigFile((string)getcwd(), $this->file_path))->getConfig();
+    }
+
     /**
      * @param string $expected_template
      * @param string $contents

tests/MethodCallTest.php

@@ -6,8 +6,6 @@ use Psalm\Context;
 use Psalm\Tests\Traits\InvalidCodeAnalysisTestTrait;
 use Psalm\Tests\Traits\ValidCodeAnalysisTestTrait;
 
-use function class_exists;
-
 use const DIRECTORY_SEPARATOR;
 
 class MethodCallTest extends TestCase
@@ -17,10 +15,6 @@ class MethodCallTest extends TestCase
 
     public function testExtendDocblockParamType(): void
     {
-        if (class_exists('SoapClient') === false) {
-            $this->markTestSkipped('Cannot run test, base class "SoapClient" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php

tests/MethodSignatureTest.php

@@ -7,8 +7,6 @@ use Psalm\Exception\CodeException;
 use Psalm\Tests\Traits\InvalidCodeAnalysisTestTrait;
 use Psalm\Tests\Traits\ValidCodeAnalysisTestTrait;
 
-use function class_exists;
-
 use const DIRECTORY_SEPARATOR;
 
 class MethodSignatureTest extends TestCase
@@ -18,10 +16,6 @@ class MethodSignatureTest extends TestCase
 
     public function testExtendSoapClientWithDocblockTypes(): void
     {
-        if (class_exists('SoapClient') === false) {
-            $this->markTestSkipped('Cannot run test, base class "SoapClient" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php
@@ -52,10 +46,6 @@ class MethodSignatureTest extends TestCase
 
     public function testExtendSoapClientWithNoDocblockTypes(): void
     {
-        if (class_exists('SoapClient') === false) {
-            $this->markTestSkipped('Cannot run test, base class "SoapClient" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php
@@ -78,10 +68,6 @@ class MethodSignatureTest extends TestCase
 
     public function testExtendSoapClientWithParamType(): void
     {
-        if (class_exists('SoapClient') === false) {
-            $this->markTestSkipped('Cannot run test, base class "SoapClient" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php
@@ -249,9 +235,6 @@ class MethodSignatureTest extends TestCase
     {
         $this->expectExceptionMessage('ImplementedParamTypeMismatch');
         $this->expectException(CodeException::class);
-        if (class_exists('SoapClient') === false) {
-            $this->markTestSkipped('Cannot run test, base class "SoapClient" does not exist!');
-        }
 
         $this->addFile(
             'somefile.php',
@@ -286,10 +269,6 @@ class MethodSignatureTest extends TestCase
         $this->expectException(CodeException::class);
         $this->expectExceptionMessage('MethodSignatureMismatch');
 
-        if (class_exists('SoapClient') === false) {
-            $this->markTestSkipped('Cannot run test, base class "SoapClient" does not exist!');
-        }
-
         $this->addFile(
             'somefile.php',
             '<?php

tests/TestConfig.php

@@ -20,6 +20,10 @@ class TestConfig extends Config
     {
         parent::__construct();
 
+        foreach ($this->php_extensions as $ext => $_enabled) {
+            $this->php_extensions[$ext] = true;
+        }
+
         $this->throw_exception = true;
         $this->use_docblock_types = true;
         $this->level = 1;