PHP 8.5: Warning "unexpected NAN value was coerced to string" when binding NAN to a parameter with PDO

[aaa2000]

Description

The following code with PHP 8.5:

<?php
$pdo = new PDO("sqlite::memory:");
$stmt = $pdo->prepare("
    WITH dummy(value) AS (VALUES ('1'), ('2'))
    SELECT * FROM dummy WHERE value = :value
");
$stmt->bindValue(":value", NAN, PDO::PARAM_STR);
$stmt->execute();
var_dump($stmt->fetchAll())

Resulted in this output:

Warning: unexpected NAN value was coerced to string... 

array(0) {
}

But I "expected" this output instead:

array(0) {
}

When binding a NAN value to a PDO statement using PDO::PARAM_STR in PHP 8.5, a warning is emitted:

Warning: unexpected NAN value was coerced to string

This warning does not occur in PHP 8.4, and the behavior is consistent with the PHP 8.5 Warnings RFC. So this might not be a bug, in that case, sorry for the inconvenience.

If I want to keep the current logic and suppress the warning, I think I have to do:

$stmt->bindValue(':value', is_nan($value) ? 'NAN' : $value, PDO::PARAM_STR);

but in my case I depend on the doctrine ORM...

Notes:

• PostgreSQL accepts "NAN" as a valid string representation not SQLite (that I used in the reproduction code)
• INF and -INF do not trigger this warning

PHP Version

PHP 8.5.0 (cli) (built: Nov 20 2025 19:48:03) (NTS)
Copyright (c) The PHP Group
Built by https://github.com/docker-library/php
Zend Engine v4.5.0, Copyright (c) Zend Technologies
    with Zend OPcache v8.5.0, Copyright (c), by Zend Technologies

Operating System

No response

[iluuu1994]

Hi @aaa2000. The warning looks correct, as NAN to string coercion is exactly what happens. How exactly NaN is handled depends on the SQL vendor. You can pass "NAN" manually, and it should have the same behavior.

[aaa2000]

Okay, thanks for the answer, that's what I assumed. Sorry for the inconvenience.

[iluuu1994]

No worries, there's no inconvenience.