Builtin functions are assumed to be pure

vimeo · Aug 7, 2019 · 955899a · 955899a
1 parent b5eb63b
commit 955899a
Show file tree

Hide file tree

Showing 3 changed files with 22 additions and 2 deletions.
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/FunctionCallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/FunctionCallAnalyzer.php
@@ -599,7 +599,7 @@ public static function analyze(
         }
 
         if ($context->pure) {
-            if (!$function_storage || !$function_storage->pure) {
+            if ($function_storage && !$function_storage->pure) {
                 if (IssueBuffer::accepts(
                     new ImpureFunctionCall(
                         'Cannot call an impure function from a pure context',

diff --git a/src/Psalm/Internal/Codebase/Reflection.php b/src/Psalm/Internal/Codebase/Reflection.php
@@ -368,6 +368,8 @@ public function registerFunction($function_id)
                 }
             }
 
+            $storage->pure = true;
+
             $storage->required_param_count = 0;
 
             foreach ($storage->params as $i => $param) {

diff --git a/tests/PureAnnotationTest.php b/tests/PureAnnotationTest.php
@@ -33,6 +33,15 @@ function filterOdd(int $i, A $a) : ?int {
                         return null;
                     }',
             ],
+            'pureFunctionCallingBuiltinFunctions' => [
+                '<?php
+                    namespace Bar;
+
+                    /** @psalm-pure */
+                    function lower(string $s) : string {
+                        return substr(strtolower($s), 0, 10);
+                    }',
+            ],
         ];
     }
 
@@ -90,9 +99,18 @@ function filterOdd(int $i, A $a) : ?int {
                 '<?php
                     namespace Bar;
 
+                    function impure() : ?string {
+                        /** @var int */
+                        static $i = 0;
+
+                        ++$i;
+
+                        return $i % 2 ? "hello" : null;
+                    }
+
                     /** @psalm-pure */
                     function filterOdd(array $a) : void {
-                        extract($a);
+                        impure();
                     }',
                 'error_message' => 'ImpureFunctionCall',
             ],