[imp] Message content not displayed after upgrade to PHP 7.3

[Arjen de Korte]

Citeren Arjen de Korte <build+horde at de-korte.org>:

> Citeren Arjen de Korte <build+horde at de-korte.org>:
>
>> Just a heads-up for those that what to upgrade to PHP 7.3: it seems  
>> like there are some incompatibilities with Horde (master) in  
>> handling regular expressions.
>>
>> Some (but not all) messages will not display content.

It looks like HTML mail is displayed correctly and text-only ones don't.

>> The following is logged for each message:
>>
>> 2018-12-25T12:47:27+01:00 WARN: horde [imp] PHP ERROR:  
>> preg_replace_callback(
>> ): Compilation failed: invalid range in character class at offset  
>> 68 [pid 207
>> 6 on line 99 of "/usr/share/php7/PEAR/Horde/Text/Filter.php"]
>> 2018-12-25T12:47:27+01:00 WARN: horde [imp] PHP ERROR:  
>> preg_replace_callback(
>> ): Compilation failed: invalid range in character class at offset  
>> 649 [pid 20
>> 76 on line 99 of "/usr/share/php7/PEAR/Horde/Text/Filter.php"]
>>
>> This may be due to the stricter interpretation of character ranges  
>> in classes.
>
> Note that the message content is available. I can reply to such a  
> message (like the one quoted above) just fine. So the trouble seems  
> to be in rendering messages, rather than grabbing them from the IMAP  
> server.