FFI stubs improvement

stubs/extensions/ffi.phpstub

@@ -19,9 +19,10 @@ namespace {
         }
 
         /**
+         * Note: Official docs say this could return `null`, but it throws exceptions instead.
          * @param \FFI\CType|string $type
          */
-        public static function new($type, bool $owned = true, bool $persistent = false): ?\FFI\CData
+        public static function new($type, bool $owned = true, bool $persistent = false): \FFI\CData
         {
         }
 
@@ -106,6 +107,25 @@ namespace {
         public static function isNull(\FFI\CData $ptr): bool
         {
         }
+
+        public function __call(...$values)
+        {
+        }
+
+        /**
+         * @param mixed $value
+         * @return mixed $value
+         */
+        public function __set(string $key, $value)
+        {
+        }
+
+        /**
+         * @return string|int|float|\FFI\CData|null
+         */
+        public function __get(string $key)
+        {
+        }
     }
 
 }
@@ -115,9 +135,36 @@ namespace FFI {
     /**
      * @since 7.4.0
      */
-    final class CData
+    final class CData implements \Countable, \ArrayAccess, \Countable, \Traversable
     {
+        /**
+         * @return bool
+         */
+        public function offsetExists($offset)
+        {
+        }
+
+        /**
+         * @return mixed|null
+         */
+        public function offsetGet($offset)
+        {
+        }
 
+        /**
+        * @param mixed|null $value
+        * @return void
+        */
+        public function offsetSet($offset, $value)
+        {
+        }
+
+        /**
+        * @return void
+        */
+        public function offsetUnset($offset)
+        {
+        }
     }
 
     /**

tests/FFITest.php

@@ -0,0 +1,87 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psalm\Tests;
+
+use Psalm\Tests\Traits\ValidCodeAnalysisTestTrait;
+
+/**
+ * tests for the handling of code using the PHP FFI extension
+ *
+ * https://www.php.net/manual/en/book.ffi.php
+ */
+class FFITest extends TestCase
+{
+    use ValidCodeAnalysisTestTrait;
+
+    public function providerValidCodeParse(): iterable
+    {
+        return [
+            // Examples are from https://www.php.net/manual/en/ffi.examples-basic.php
+            // Some of them needed tweaks, e.g. due to unsafe use of var_dump().
+            'Example #1 Calling a function from shared library' => [
+                'code' => '<?php
+                    $ffi = FFI::cdef(
+                        "int printf(const char *format, ...);", // this is a regular C declaration
+                        "libc.so.6"
+                    );
+                    $ffi->printf("Hello %s!\n", "world");
+                ',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '7.4',
+            ],
+            'Example #3 Accessing existing C variables' => [
+                'code' => '<?php
+                    $ffi = FFI::cdef(
+                        "int errno;", // this is a regular C declaration
+                        "libc.so.6"
+                    );
+                    echo $ffi->errno;
+                ',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '7.4',
+            ],
+            'Example #5 Working with C arrays' => [
+                'code' => '<?php
+                    // create C data structure
+                    $a = FFI::new("long[1024]");
+                    // work with it like with a regular PHP array
+                    $size = count($a);
+                    for ($i = 0; $i < $size; $i++) {
+                        $a[$i] = $i;
+                    }
+                    $sum = 0;
+                    /** @psalm-suppress MixedAssignment */
+                    foreach ($a as $n) {
+                        /** @psalm-suppress MixedOperand */
+                        $sum += $n;
+                    }
+                ',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '7.4',
+            ],
+            'Example #6 Working with C enums' => [
+                'code' => '<?php
+                    $a = FFI::cdef(
+                       "typedef enum _zend_ffi_symbol_kind {
+                            ZEND_FFI_SYM_TYPE,
+                            ZEND_FFI_SYM_CONST = 2,
+                            ZEND_FFI_SYM_VAR,
+                            ZEND_FFI_SYM_FUNC
+                        } zend_ffi_symbol_kind;"
+                    );
+                    echo $a->ZEND_FFI_SYM_TYPE;
+                    echo $a->ZEND_FFI_SYM_CONST;
+                    echo $a->ZEND_FFI_SYM_VAR;
+                ',
+                'assertions' => [],
+                'ignored_issues' => [],
+                'php_version' => '7.4',
+            ],
+        ];
+    }
+}