Control: tags -1 + sid As can be seen from the build log, the resolver installs both php7.0 and php7.1 dependencies (namely php7.1-common and php7.1-xml), resulting in a php cli environment based on 7.0 that does not have the xml/xsl modules available. This also happens in my sbuild chroot. It cannot happen in Stretch, though, because php7.1-xml is only available in unstable. So this bug does not affect Stretch.
I suspect the cause for this peculiar behaviour of the apt resolver has to do with the Build-Depends on php-xsl, which is a purely virtual package currently provided by both php7.0-xml and php7.1-xml. It goes away when I change the Build-Dependency to php-xml.
