[2.1.18] Subs-Attachments.php: Line 698, bool treated as array, forum error generated after attaching .txt or .pdf #9787

Basic Information

I am using Apache 2.4 (32-bit), PHP 8.5.10 (32-bit) and was seeing this error on every .txt or .pdf attachment.

I am not a PHP programmer so I relied on ChatGPT to identify and patch the problem.

Excuse me in advance if the etiquette for reports is supposed to exclude AI bug identification or patches.

ChatGPT:

The code treats a Boolean false as an array, and I confirmed the exact cause in your installed forum.
Both logs identify Subs-Attachments.php, line 698:

The failing code is:

$size = @getimagesize($attachmentOptions['tmp_name']);
list ($attachmentOptions['width'], $attachmentOptions['height']) = $size;

getimagesize() returns an array for supported images, but returns false when it cannot determine image dimensions. A PDF or other non-image attachment can therefore reach the next line with $size === false.

The appropriate replacement is:

$size = @getimagesize($attachmentOptions['tmp_name']);
list ($attachmentOptions['width'], $attachmentOptions['height']) =
$size !== false ? $size : array(0, 0);

This preserves image dimensions and uses zero dimensions for other attachments. The existing SVG handling immediately afterward remains applicable.

I reproduced the exact warning using your local PHP 8.5.10 executable. The guarded version completed without that warning. The logs alone don’t identify which uploaded files caused it; an unreadable or damaged image could also return false.

Attached is a patch from ChatGPT for the line in question. Search 'ChatGPT' to locate the patch.

Subs-Attachments.php

Steps to reproduce

1. Create a new post, attach a .pdf, upload and finalize post.
2. Error is generated in Admin log.

Expected result

No response

Actual result

No response

Version/Git revision

2.1.18

Database Engine

MySQL

Database Version

No response

PHP Version

8.5.10

Logs

Additional Information