sfp-psalm-typed-local-variable-plugin

finding mismatch type assignment in function/method scope with psalm.

Installation

$ composer require --dev struggle-for-php/sfp-psalm-typed-local-variable-plugin
$ vendor/bin/psalm-plugin enable struggle-for-php/sfp-psalm-typed-local-variable-plugin

latest version supports psalm ^4.

Demo

<?php
class Entity{}
interface Repository
{
    public function findOneById(int $id): ?Entity;
}
interface Mock{}
/** @return \DateTimeInterface&Mock */
function date_mock() {
    return new class('now') extends \DateTime implements Mock{};
}

class Demo
{
    /** @var Repository */
    private $repository;

    function typed_by_phpdoc() : void
    {
        /** @var string|null $nullable_string */
        $nullable_string = null;
        $nullable_string = "a";
        $nullable_string = true; // ERROR
    }

    function typed_by_assignement() : void
    {
        $date = new \DateTimeImmutable('now');
        if (\rand() % 2 === 0) {
            $date = new \DateTime('tomorrow'); // ERROR
        }

        $bool = true; //direct typed without doc-block
        $bool = false; // ok (currently, this plugin treats true|false as bool)
        $bool = 1; // ERROR
    }

    function mismatch_by_return() : void
    {
        /** @var Entity $entity */
        $entity = $this->repository->findOneById(1); // ERROR
    }

    function works_with_intersection() : void
    {
        /** @var \DateTimeInterface&Mock $date */
        $date = new \DateTime('now'); // ERROR
        $date = date_mock(); // success
    }
}

$ ./vendor/bin/psalm -c demo.psalm.xml
Scanning files...
Analyzing files...

E

ERROR: InvalidScalarTypedLocalVariableIssue - demo/demo.php:23:28 - Type true should be a subtype of null|string
        $nullable_string = true; // ERROR


ERROR: InvalidTypedLocalVariableIssue - demo/demo.php:30:21 - Type DateTime should be a subtype of DateTimeImmutable
            $date = new \DateTime('tomorrow'); // ERROR


ERROR: InvalidScalarTypedLocalVariableIssue - demo/demo.php:35:17 - Type 1 should be a subtype of bool
        $bool = 1; // ERROR


ERROR: InvalidTypedLocalVariableIssue - demo/demo.php:41:19 - Type Entity|null should be a subtype of Entity
        $entity = $this->repository->findOneById(1); // ERROR


ERROR: InvalidTypedLocalVariableIssue - demo/demo.php:47:17 - Type DateTime should be a subtype of DateTimeInterface&Mock
        $date = new \DateTime('now'); // ERROR


------------------------------
5 errors found
------------------------------

Plugin Issues

All issue names has TypedLocalVariableIssue suffix.

• MixedTypeCoercionTypedLocalVariableIssue
  • nearly MixedArgumentTypeCoercion

eg.

function foo(array $a) : void {
    /** @var string[] $x */
    $x = $a;
}

• TypeCoercionTypedLocalVariableIssue
  • nearly ArgumentTypeCoercion

eg.

class A {}
class B extends A {}

function takesA(A $a) : void {
    /** @var B $b */
    $b = $a;
}

• InvalidScalarTypedLocalVariableIssue

  • nearly InvalidScalarArgument

• InvalidTypedLocalVariableIssue

  • nearly InvalidArgument

If you want suppress specific issue, please setting psalm.xml like below.

<issueHandlers>
  <PluginIssue name="MixedTypeCoercionTypedLocalVariableIssue">
      <errorLevel type="suppress">
          <file name="src/Foo.php"/>
      </errorLevel>
  </PluginIssue>
</issueHandlers>

Disclaimer

This is Experimental plugin.

Limitation

• NOT support global variables.
• NOT support variables in namespace.
• NOT support Variable variables
• Non-each inline VariableReference.
  • eg.

/** @var string $var1 */
/** @var bool $var2 */
$var1 = 'string'; // cannot determine type for $var1

// should fix like below
/** @var string $var1 */
$var1 = 'string';
/** @var bool $var2 */
$var2 = true;

Todo

• optional setting for only from_docblock typed.