I ran into a major bug in phpBB doing a conversion for a client to phpBB 3.3.5 recently.
A conversion is when you migrate from a different forum solution to phpBB. It’s also used for phpBB 2, which was retired in 2007, as the architecture for phpBB 3 is completely different than phpBB 2. You would think after 15 years there would be no more phpBB 2 boards left. My clients would disagree. I get probably half a dozen of these a year, almost all from phpBB 2. It is amazing that there are so many of these boards still around. phpBB 2 was very simple, but very reliable.
The conversions used to be painful but the convertor software has become much more reliable. Now most conversions have minor issues at best. So I wasn’t expecting any trouble when I did a recent phpBB 2 conversion other than a lot of waiting around: this board had 3.9 million posts, 1 million private messages and 60GB of attachments.
But there was a problem that manifested as soon as I hit the submit button after entering the old database information. I got a HTTP 500 error and the PHP error log generated some really hard to understand error messages.
I spent the better part of two days puzzling it out, eventually assuming that it was environmental on the client’s server. So I moved a 4GB database and 60GB of files to my machine to try it there, but it happened again.
To shorten a long story, the convertor failed because configuration information for the conversion was serialized and stored in the database was not serialized properly. The configuration information contained escapes (\”, mostly). When PHP was told to unserialize these it couldn’t, returning NULLs where an array would have been expected. With a lot of trial and error I found if I removed most of these escapes it would unserialize properly and I could continue the conversion. But clearly something had changed in the conversion software.
I reported it but apparently the phpBB Group already knew of the error, and it will be fixed in phpBB 3.3.6. It was not reported in their support forum, which is where serious problems to a release are usually posted. Most likely it just got overlooked, but also after 15 years the phpBB Group probably figured hardly anyone runs conversions anymore, so why bother to highlight it?
There are two workarounds if you find yourself in this situation:
- Wait for phpBB 3.3.6 or higher edition as it should be fixed
- Install phpBB 3.3.4 instead of 3.3.5, run the conversion software and afterward update to phpBB 3.3.5
I tested the latter approach with another client yesterday and it worked fine.
