finfo::buffer(): Failed identify data 0:(null)

[P2T]

Description

The following code:

<?php
$data = pack('H*','fffe000000099999');
$mime_type = (new finfo(FILEINFO_MIME))->buffer($data);

Resulted in this output:

Warning: finfo::buffer(): Failed identify data 0:(null)

But I expected this output instead:
Something instead of '(null)'

PHP Version

PHP 8.3.2

Operating System

No response

[Girgias]

I'm confused, why do you expect "something instead of null" here?

What does this data represent and how should it determined?

Anyway, this looks more like a feature request for the underling libmagic library: https://www.darwinsys.com/file/ or https://bugs.astron.com/my_view_page.php

[P2T]

I'm confused, why do you expect "something instead of null" here?

What does this data represent and how should it determined?

Anyway, this looks more like a feature request for the underling libmagic library: https://www.darwinsys.com/file/ or https://bugs.astron.com/my_view_page.php

I don't know the file format. The issue is the warning with the message "null".

Proposal 1: remove the warning, return false

Proposal 2: keep the warning, change (null) to a default message

Proposal 3: keep the warning, show an actual/useful message from the lib (only in this case, this ticket could be considered as a feature request for the lib).

[ranvis]

@Girgias
The current libmagic (5.45) contains the update that fixes this case: file/file@029b824.

It appears that the identification error without error code/message is just the bug of the library.
Otherwise, error code and message should be returned from the library, as the manpage says magic_buffer() returns NULL on error.

[nielsdos]

Thanks for figuring out the upstream commit.
I'll get it backported. Additionally, I prepared a PR to update 8.4-dev to libmagic 5.45.