get_headers: array<array-key, mixed> can never contain false

[michabbb]

https://psalm.dev/r/c9c058d764

pardon, i do myself hard to understand this error, because the PHP documentation clearly says:

Returns an indexed or associative array with the headers, or false on failure.

what am I missing here ?

thanks for any help!

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/c9c058d764

<?php

$file_headers = @get_headers('https://somethinganything.dev');
$return = ($file_headers!==false && mb_stripos($file_headers[0], '404 Not Found') === false);
echo $return;

Psalm output (using commit 89ee1f1):

ERROR: RedundantCondition - 4:12 - array<array-key, mixed> can never contain false

INFO: PossiblyUndefinedIntArrayOffset - 4:48 - Possibly undefined array offset '0' is risky given expected type 'array-key'. Consider using isset beforehand.

INFO: MixedArgument - 4:48 - Argument 1 of mb_stripos cannot be mixed, expecting string

[weirdan]

Indeed, get_headers() does return false sometimes: https://github.com/php/php-src/blob/aff365871aec54c9a556d7667f131b8638d20194/ext/standard/url.c#L699-L706