We don't "need" to use the Plancake dependency, but the fact it's not just regex probably suggests it might be better in the long run.
We don't have any support for composer stuff in production - we currently just include the pre-prepared vendor repo for core for example.
So this needs a bit of work...
I'm wondering if we should just modify make-wmf-branch to look for composer.json files, run "php composer.phar update --optimize-autoloader", and then add the lot to the "Creating new wmf/1.XXwmfYY" branch commit?
Version: unspecified
Severity: enhancement