cache: File cache names are too long. Checks limiting it to 255 do not actually work properly in all cases.

First of all, there was this issue posted for Symfony here: https://github.com/symfony/symfony/issues/19363 . I encountered the same thing and spent a lot of time investigating it and came up to this: When using FileCache filenames sometimes are longer, than supported. I am using docker containers on vagrant with VBox linked shared folders. There is a limit for a FILE_NAME of 255 characters. I tried renaming some of the long filenames inside cache directories and the error switched to another folder: /var/www/html/var/cache/de~/annotations/fd -> var/www/html/var/cache/de~/annotations/44 for example. So it looks like command is able to process the first folder, but then fails on the second one, as there is also a very long filename (256 characters including extension, which should be 255).

I am using docker containers on vagrant with VirtualBox and I suspect that the vboxsf might have some FILE_NAME or PATH_NAME limitations and those are 255 and 4096 respectively.

Then I tried to reduce filenames from 256 chars and went to Doctrine\Common\Cache\FilesystemCache and changed extension from .doctrinecache.data to .doctrine.data and everything worked, I was able to clear the cache after clearing the previous one manually (it still had long files).

It led me to suspect, that the problem lies within Doctrine\Common\Cache\FileCache, getFilename() does not work properly and sometimes has wrong behaviour. I think this issue is also connected to #174 .

IMPORTANT: Issue persists only for Symfony dev environment and works fine for prod.