I was also thinking of putting the vendor directory under git control because I want to avoid having to install dependencies using 'composer install' in the course of deployment to test and prod stages. But isn't this causing an issue with platform/OS dependent content in the vendor directory? How far can the vendor directories of the same project (same state of composer.lock) differ depending on Windows, Mac, Linux as the underlying OS? I think the vendor/bin content differs between Windows and Mac as far as I can see.