I tried to get Symfony running on HHVM 3.3, because 3.2 caused some annoying issues. However, 3.3 didn’t run out of the box neither, because now it refused to parse DIC-XMLs. I’ve found the solution in one ticket, that I cannot find anymore. I found the explanation in the “inconsistencies”-file instead.

(7) Loading of external entities in the libxml extension is disabled by default for security reasons. It can be re-enabled on a per-protocol basis (file, http, compress.zlib, etc…) with a comma-separated list in the ini setting hhvm.libxml.ext_entity_whitelist.

To sum it up: To get it Symfony working again, just add this to your php.ini

hhvm.libxml.ext_entity_whitelist = file

The security implications should be relatively small, because usually you don’t have any malicious entity-files on your local disc.

For those, who want to know: file is enough, because Symfony rewrites the XML-files, so that they don’t refer to the remote locations, but to local ones within the project itself (vendor/symfony/..), because the remote ones doesn’t match the required versions and it prevents one from downloading the file each and every time the container gets rebuild.