Add a dynamic return type extension for current_time() (#60)

Co-authored-by: Viktor Szépe <viktor@szepe.net>

Author: johnbillion

extension.neon

@@ -43,6 +43,10 @@ services:
         class: SzepeViktor\PHPStan\WordPress\MySQL2DateDynamicFunctionReturnTypeExtension
         tags:
             - phpstan.broker.dynamicFunctionReturnTypeExtension
+    -
+        class: SzepeViktor\PHPStan\WordPress\CurrentTimeDynamicFunctionReturnTypeExtension
+        tags:
+            - phpstan.broker.dynamicFunctionReturnTypeExtension
 parameters:
     bootstrapFiles:
         - %rootDir%/../../php-stubs/wordpress-stubs/wordpress-stubs.php

src/CurrentTimeDynamicFunctionReturnTypeExtension.php

@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * Set return type of current_time().
+ */
+
+declare(strict_types=1);
+
+namespace SzepeViktor\PHPStan\WordPress;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Reflection\ParametersAcceptorSelector;
+use PHPStan\Type\Type;
+use PHPStan\Type\IntegerType;
+use PHPStan\Type\StringType;
+use PHPStan\Type\Constant\ConstantStringType;
+
+class CurrentTimeDynamicFunctionReturnTypeExtension implements \PHPStan\Type\DynamicFunctionReturnTypeExtension
+{
+    public function isFunctionSupported(FunctionReflection $functionReflection): bool
+    {
+        return in_array($functionReflection->getName(), ['current_time'], true);
+    }
+
+    /**
+     * @see https://developer.wordpress.org/reference/functions/current_time/
+     */
+    public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): Type
+    {
+        $argumentType = $scope->getType($functionCall->args[0]->value);
+
+        // When called with a $type that isn't a constant string, return default return type
+        if (! $argumentType instanceof ConstantStringType) {
+            return ParametersAcceptorSelector::selectFromArgs(
+                $scope,
+                $functionCall->args,
+                $functionReflection->getVariants()
+            )->getReturnType();
+        }
+
+        // Called with a constant string $type
+        switch ($argumentType->getValue()) {
+            case 'timestamp':
+            case 'U':
+                return new IntegerType();
+            case 'mysql':
+            default:
+                return new StringType();
+        }
+    }
+}

tests/data/current_time.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SzepeViktor\PHPStan\WordPress\Tests;
+
+use function current_time;
+use function PHPStan\Testing\assertType;
+use stdClass;
+
+// Integer types
+assertType('int', current_time('timestamp'));
+assertType('int', current_time('U'));
+
+// String types
+assertType('string', current_time('mysql'));
+assertType('string', current_time('Hello'));
+
+// Unknown types
+assertType('int|string', current_time($_GET['foo']));
+assertType('int|string', current_time(get_option('date_format')));
+
+// Unsupported types
+assertType('int|string', current_time(new stdClass));
+assertType('int|string', current_time(false));

tests/testTest.php

@@ -15,6 +15,7 @@ class DynamicReturnTypeExtensionTests extends TypeInferenceTestCase
     public function dataFileAsserts(): iterable
     {
         // path to a file with actual asserts of expected types:
+        yield from $this->gatherAssertTypes(__DIR__ . '/data/current_time.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/get_comment.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/get_object_taxonomies.php');
         yield from $this->gatherAssertTypes(__DIR__ . '/data/mysql2date.php');