When I add a php_extensions: block to my Boxfile, it appears to make the default extensions disappear?
Specifically, I enabled APC with it, and then I no longer had the mysql extension?
Is this normal? Happened on more than one deploy - so don't think it was a one off error. Do I need to put all the default extensions in as soon as I specify any?
That is normal. Because mysql is commonly needed, it’s installed by default when there aren’t any extensions specified in the Boxfile. But as soon as you specify any extensions in the Boxfile, you override the default. So you do need to specify mysql along with your other extensions in the Boxfile.