Monday, October 26, 2009

MacPorts headaches... follow-up

Some of these issues apparently have to do with the order in which things are done and may also depend on the fact that some of these packages require native C-language extensions.

I wanted to work with nokogiri to do some XML parsing. Given my previous post, I figured I'd better install this using MacPorts, which I did:
     sudo port install nokogiri
That was pretty straight-forward and worked quickly. However, when I went to irb to check things out, I got the following message:

irb(main):001:0> require 'nokogiri'
HI.  You're using libxml2 version 2.6.16 which is over 4 years old and has
plenty of bugs.  We suggest that for maximum HTML/XML parsing pleasure, you
upgrade your version of libxml2 and re-install nokogiri.  If you like using
libxml2 version 2.6.16, but don't like this warning, please define the constant
So I quit irb and installed libxml2
     sudo port install libxml2
which also went just fine.  Unfortunately, nokogiri still gave me that long warning message.

What I had to do was re-install nokogiri so that it would recognize the new version of libxml2 (which was now in the /opt/local tree) and then everything worked fine.

Seems like I can get things to work now, but having to remember previous dependencies and re-install packages to pick up those new items isn't going to be fun.

MacPorts headaches...

Recently I started doing some of my development work on a little MacBook. Pretty nice as I drop down into terminal, have all the power of *nix (FreeBSD-based in this case), and still have Mac niceties available to me, such as MacVim for editing.

Everything is rocking along just fine: I've got Cucumber and RSpec running and working my way thru "The RSpec Book" (pretty useful so far). However, I needed to install FXruby so that I could do some graphical work and figured this would be no problem. Turned out to be a little tricky and I had to remember an issue I ran into a while back on a Linux system.

First off, this won't work:
     gem install fxruby
It'll install that gem alright, but that's not enough to get things running: you have to get Fox installed as well and that doesn't come along with the gem.

Of course, to do that, you have to install MacPorts which is actually relatively painless (see the MacPorts Guide for how to do this).

Once you've done this, then you can install the complete FXRuby collection of stuff (see the FXRuby Book at
     sudo port install rb-fxruby
and it's a very large collection indeed: it took over 1 hour on my machine.

The only hitch I ran into was having too old a version of the Mac XTools package, so that was another 800Megs of download and an install. If you do this make sure you get the right version: XTools 3.1 is for OS X 10.5 and XTools 3.2 is for 10.6. Check this first or you'll spend most of an hour installing fxruby only to have it complain about the wrong XTools version and you'll have to start over.

MacPorts updates your ~/.profile or ~/.bash_profile file (note that the MacPorts install docs only mention ~/.profile and I had to dig a bit to find that they had properly modified my ~/.bash_profile file) so that your system can find the added programs...

But that's not quite everything you have to do and here was the gotcha for me. Even after I went through all this, I kept getting strange messages out of my test runs, things like:
  "unable to load file ubygems"
(the missing 'r' is not a typo: that was the exact error message) when executing the "require 'rubygems'" statement.

I tried adding the command:
      export RUBYOPT=rubygems
to my profile so that I wouldn't have to add a require 'rubygems' statement but that didn't solve the problem.

BTW, when I went to the RubyGems Guide, they said to use the -rubygems option on the ruby command line, but that also generated the same error.

After a little more digging, I found the problem: MacPorts installs everything in /opt/local, which is not where the normal gem command installs things (if you do a simple "gem install ' they wind up in /usr/bin).  Thus, after MacPorts was installed, ruby got a tad confused and couldn't find everything it needed.  Then I remembered what I had run into when I was working on my Linux box: trying to install a LAMP stack: everything got put into /opt/local, but then it was out of the normal stream of things and there were ongoing problems. I finally bit the bullet in that case, removed the LAMP stack, and manually installed everything into their default locations. Life has been pretty good in Linux-land ever since.

The solution? Install rubygems using MacPorts so that my FXRuby could find what it needed. That was a simple:
     sudo port install rb-rubygems
and now my ruby apps would run again, load the gems, and I had a simple FXRuby app running.

Quite frankly, I'm not sure of all the nitty-gritty details of this problem and I'm not even sure that I won't have further problems downstream when I want to use another gem, but I'll face that problem when I come to it. If anyone has a definitive answer as to WHY this happened and a better approach to Mac OS X gem  installation, I'm all ears.