Compact index case collisions

[indirect]

Related to rubygems/rubygems.org#1356, there is a problem compact index clients: if you install the gem Rack, Bundler will download the file from /info/Rack and save it to the filesystem. If you later install the gem rack, Bundler will download the file from /info/rack and save it to the filesystem. But most filesystems are not case-sensitive. So this means that the compact index client will be overwriting the cache file /info/rack back and forth every time one of these conflicting gems is installed. :/ We can fix this in the client by changing the filename for caching capitalized gem names.

I propose that we add a hash to the end of the cache file for any gem name that contains any characters that can't be represented on the filesystem:

info_file = [info_file.gsub(/[^a-z0-9_-]/, ''), md5(info_file)].join("-") if info_file =~ /[^a-z0-9_-]/