mb_detect_encoding difference between PHP 8.1.28 and 8.3.6

[staabm]

Description

The following code:

<?php

var_dump(mb_detect_encoding("CMS-Seite l\xF6schen"));

Resulted in this output on 8.1.28:

bool(false)

Resulted in this output on 8.3.6:

string(5) "ASCII"

https://3v4l.org/TY6vO

But I expected: no sure what to expect and which one is right/wrong ;)

PHP Version

8.3.6

Operating System

Ubuntu24.04 lts

[staabm]

//cc @alexdowad

[damianwadley]

This is documented in the 8.3 migration guide:

https://www.php.net/manual/en/migration83.other-changes.php

mb_detect_encoding()'s "non-strict" mode now behaves as described in the documentation. Previously, it would return false if the same byte (for example, the first byte) of the input string was invalid in all candidate encodings. More generally, it would eliminate candidate encodings from consideration when an invalid byte was seen, and if the same input byte eliminated all remaining encodings still under consideration, it would return false. On the other hand, if all candidate encodings but one were eliminated from consideration, it would return the last remaining one without regard for how many encoding errors might be encountered later in the string. This is different from the behavior described in the documentation, which says: "If strict is set to false, the closest matching encoding will be returned."

If you want an exact-or-nothing match then use the $strict parameter. https://3v4l.org/bLYlB

[staabm]

great catch - thank you so much.