Property description special property is trimmed incorrectly on saving

[alex-mashin]

PHP 8.3.10, MW 1.39.8, SMW 4.2.0.

An ask query fails silently, showing an exception if debugging is on. The results of the ask query contain Unicode characters, which can be illegal, if some non-Unicode aware string operations had been applied to it.

I have traced the exception, so far, to includes/MagicWord.php; MagicWord::matchAndRemove(). preg_replace_callback() returns null; which is passed as subject string to preg_replace_callback() on the next magic word causing an exception.

The magic word ($this->getRegex()) causing error is /__NOFACTBOX__/iu (removing u removes the error but another error happens later again with a null instead of a string). The $text is a longish result of a successful SMW query (widetable format), containing non-Latin characters; and also a � terminating <span class="smwttcontent"> with a property description. I suspect that the property description had been trimmed incorrectly.

The property Has property description for one of the queried properties is set to an evidently illegal Unicode string finishing with a �.

UPDATE: The value is set to {{#set: Has property description = Свойство для хранения регулярного выражения с захватами-селекторами для разбора страницы с форматом <code>text</code>. селекторы в этом случае представляют захваты. Используется в подъобъектах.@ru}}. However, it is stored as Свойство для хранения регулярного выражения с захватами-селекторами для разбора страницы с форматом <code>text</code>. селекторы в этом случае представляют захваты. Ис�.

It seems to be trimmed somewhere before saving, but trimmed incorrectly, disregarding that it contains non-Latin Unicode sequences.