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Ruby on Rails – Disturbing Errors

Excuse my efforts in going slightly off topic in an attempt to help out anyone else who may have struck this issue.
I'd been given a good challenge by a friend: mimic an install of ruby on rails on a local VM. I'd never worked with ruby before and google'd for a tutorial. Before I knew it I had Turnkey Linux's Ruby Appliance up and running on Oracle's Virtual Box on 64-Bit Windows 7.

I wont go in to deployment steps here... it's all covered on the web. The basic concepts were to point an apache virtual host at a new directory in /var/www and then browse to the application. To my delight it started, throwing an error. I hadn't even configured a thing yet, so how could I expect it to run?

After configuring the Facebook connector and the database connection the site came up and I could log in and muck around. It wasn't long until I hit the following error. It was only on a specific data class that extended the ActiveRecord interface and only when checking if the data was valid or trying to save it. I could happily create the class and change attributes...

Wrong number of arguments (1 of 0)

What the hell... I hadn't seen ruby exceptions before, so I started to dig. The RAILS_ENV environment variable was set to 'development' and so there was a 'development.log' file sitting in the 'log' directory inside the application. This provided a stack trace and a few other bits and pieces.

After a lot of code commenting and uncommenting I narrowed it down to the 'save' method of the specific data item class. This was inherited from the ActiveRecord::base class and I had no say in what it did or how it did it. I did know that it was expecting no arguments, so that's where the '0' came from in the error, but I was also not passing it any arguments, so where the hell did the '1' come from!?!?!

I then tried the 'valid?' call as well... same result.

I chose to override the 'save' function in the model file by using a pass through... all of a sudden the code continued (after hours of exceptions) and the next related table row creation had a null foreign key for the item that should have been saved. It turns out that by creating a pass through I bypassed the entire 'save' method and therefore didn't attempt to write anything to the db. As soon as I tried to use the base 'save'I got the same error but now in the model file.

I was stuck... so I tried to bring up the debugger via the mini WEBrick server. It, unfortunately, didn't give me any more information than what the development.log file had provided.

Next I tried downgrading and upgrading ruby and rails. I was impressed with the 'gem' system... but nothing helped.

The final step was to google more and more... I had already tried gutting my model implementation (there was extra code in the for other tasks) but none of this changed the inability to call 'save'. All of a sudden one google search came across someone mentioning something about a 'reserved word'.... I google'd further.

Reserved Words

It seems that Ruby has a few words that you MUST NOT GO NEAR if you want your code to work. The main issue is that, when you do, you'll have no idea what you have done as the error message that results has NOTHING TO DO WITH the actual problem. It turns out that after browsing to a post by someone with a similar problem I saw the comment stating that they had used the word 'notify' for a column name.

... so had the original developer of the code I had worked on ...

There was no response to the post that pointed this out in the previous link, so that either means the original author was too ashamed and it was the correct fix, or they found the real fix and never got back to this.

Either way, I corrected my database by changing 'notify' to 'notify_opp' and ... fkn presto ... 10 hours of debugging resulted in a SUCCESS!

Further information on these magical reserved creatures

Ok, the fun part... in hind-sight I've done a little research and there are sites indicating what 'words' are 'reserved' for ruby. Unfortunately, not all of them say that 'notify' is!



Be bloody careful with errors from ruby that don't make sense and don't spend too long digging in to a dead end.
Be diligent with your google searches too.

I spent a lot of time debugging this and I hope this post helps out others in the same scenario.


About stevenh

Trains... trains... trains... + Electronics + Japan.
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