Tuesday, July 27, 2010

mapper.rb:143:in `default_controller_and_action': missing :action (ArgumentError)

I'm trying out Rails 3 for a small web project we need done at work. After spending more time than I wanted yesterday getting everything configured correctly on my Mac (namely mysql 64 bit), I was finally ready to start generating some MVC action. I followed the steps on the http://guides.rails.info/getting_started.html Rails 3 intro page to generate a controller for my home index. This added a route to my routes.rb,

get "home/index"

I thought I'd get fancy also add a root controller and view for my website, so I coped that and slightly modified it to

root :to => "home/index"

Cool. Next, I went ahead and tried to generate a new scaffold for my first model, but uh oh, there was a problem!

/Library/Ruby/Gems/1.8/gems/actionpack-3.0.0.beta4/lib/action_dispatch/routing/mapper.rb:143:in `default_controller_and_action': missing :action (ArgumentError)
from /Users/.../Code/.../config/routes.rb:2
from /Library/Ruby/Gems/1.8/gems/railties-3.0.0.beta4/lib/rails/commands.rb:16
from script/rails:6:in `require'
from script/rails:6

My first reaction was, "!@# yet another problem with Rails 3 and my system," but after some searching for the error turned up nothing, I decided that I had probably screwed something up. Looking a little more closely at the stack trace of the error, I identified that the scaffold generation was in part based on code from my own app and not just the rails gems. Hmm, probabilities rising that I'm the culprit.

The error says that the default controller is missing an action. I checked out the gem, mapper.rb, and saw that it's parsing out some variable named "to" for a controller and action. I then opened up my routes.rb and saw that line of copied code, root :to => "home/index". I then thought back to the new rails syntax that I'd learned in the video tutorials and immediately realized my folly. One quick change,

root :to => "home#index"

and the generator is back to working. Although it can definitely be a pain dealing with open source software, it certainly is nice to be able to see the source of your problems.

Wednesday, July 7, 2010

Migrating from svn to git

Several tutorials have already documented the necessary steps for the conversion from svn to git (http://www.gitready.com/beginner/2009/02/04/converting-from-svn.html), so I won't reiterate any of that. What made our migration tricky were two things:
  1. SVN commits without authors
  2. No tags, branches, or trunk paths
The second was easy to fix actually. I didn't specify any flags for standard layout or tags/branches in the git svn clone command. The second took a little bit of guess work. Before I begin, I'll point out that I used the script (after cleaning up the leading and trailing white space)

svn -q log | grep ^r | cut -d '|' -f 2 | sort | uniq > authors.txt

as conveniently provided in the comments to one of the tutorials. Just to make life easy, I used the following VI macro to fill out the definitions in the file,

yeA= ^[pa <^[pa@domain.com>^[j0

I noticed a blank line in the file, which was generated because of commits to the repo with no user name -- literally just the empty string. Big deal, I just removed it. When I tried to run the "git svn clone" though, it puked when it got to those revisions:

$>git svn clone svn://svn.domain/project -A authors.txt
Author: (no author) not defined in authors.txt file

I googled and found a support article, http://support.github.com/discussions/repos/2690-authors-not-defined-on-svn-import, which didn't actually solve the problem, just avoided it. It turned out the fix was actually easier than I thought. I added the following line to the authors file:

(no author) = no_author