Undefined variable in PHPStan but it's declared elsewhere

Question

How do you deal with these scenarios in PHPStan:

1. Say you're using plain PHP as template engine. E.g.,

// view.php

<b><?=$foo?></b>

---

2. Say you have 2 files a.php and b.php

// a.php     
$foo = 'bar';

// b.php     
require 'a.php';     
echo $foo;

---

PHPStan will both report this as Undefined variable: $foo

How do you deal with this? Can PHPStan be configured to somehow execute your app so it knows that these variables are actually defined during runtime?

Answer 1

You can try to use the phpstan.neon solution provided in phpstan#104 (comment):

You can ignore error for specific variables by using regular expressions, even in specific directories. In your case you can use:

parameters:
    ignoreErrors:
        -
            message: '#Undefined variable: \$foo.*#'
            path: my/directory/*

/** @var string $foo */

echo $foo; // No error

echo $unintededUndeclaredVariable; // Error

Answer 2

All you need to do is perform a check to ensure the variable is set.

e.g.

if (isset($foo)) {
    echo $foo;
}

or something like the following if you're not wanting to wrap all your code in an if.

if (! isset($foo)) {
    throw new Exception('$foo not set');
}