My turn to put in a few notes on what I did to get Rails to work nice with my newly updated Mac OS: Snow Leopard.  I got most of my information from Riding Rails blog post here: http://weblog.rubyonrails.org/2009/8/30/upgrading-to-snow-leopard.  I would recommend reading that through, but I found a few new things along the way:

Save your .bash_profile and your paths before doing the upgrade to Snow Leopard, you’ll need them later.

Backup your databases, and be ready to reload them in after this is all done since we need to reinstall mysql with the 64 bit version

DO NOT use the latest mysql gem 2.8.x, it doesn’t work.  Use the 2.7 version instead like this: sudo env ARCHFLAGS=”-arch x86_64” gem install mysql —version 2.7 — —with-mysql-config=/usr/local/mysql/bin/mysql_config

You must reinstall MacPorts before running the port commands listed in the blog post, you can now grab the latest Snow Leopard binary package here

You will have to upgrade —force install with your MacPorts to get the libraries updated correctly.  Takes a long time!  If any fail, just try deactivating the failed one first, then uninstalling it with -f, then reinstalling it.  If it’s good, you will need to restart the upgrade —force install once more.  This will help resolve the issues there.

Use the script they have at the bottom of the post to see which gems you want to reinstall

After a lengthy MacPorts update, reinstalling gems, figuring out that I need the mysql 2.7 gem, getting git and some other paths like mysql back into my environment, everything fired right back up.  Now I have to reload my databases and I should be good to go.

Hope you guys get your stuff working!  If anything, read the comment thread on the Riding Rails blog, that’ll help a ton!