I just upgraded from ubuntu 14.04 to ubuntu 15.04. Since then uploading attachments using the attachment plugin doesn't work anymore in ikiwiki. It prints a "failed!" message. Any idea what may be wrong here and how to fix it?

ikiwiki version 3.20141016.2

/var/log/apache2/error.log

gives this:

Died at /usr/share/perl5/IkiWiki/CGI.pm line 497.

I think this is probably Debian bug #786587, which ikiwiki has worked around since 3.20150610 (Debian bug #786586). If so, then it is already fixed, but not in the version you have. You could report an Ubuntu bug asking for ikiwiki commit 7a52c87 or CGI.pm commit e4500cf to be backported, although in practice bugs in universe packages are unlikely to get fixed in an Ubuntu stable release.

To work around this, you might be able to apt-get remove libcgi-pm-perl and use the older version of CGI.pm that is shipped with Perl. --smcv

Thanks, I just opened a bug report on launchpad.