Print out a meaningful error when ActiveRecord::ReadOnlyRecord is raised

[frankywahl]

Currently, there is no messages which get printed out. Convoluted system
may have hooks that create other objects in which case we only fail with
no messages. This commit changes this information allowing you to know
which object is the one that actually raised the error.

[rafaelfranca]

Could you show a example of the generated message?

[frankywahl]

I've created an example here: https://github.com/frankywahl/rails_examples

If you run rake example you will see the error I'm speaking about due to https://github.com/frankywahl/rails_examples/blob/master/app/models/foo.rb#L3-L5

But as you will see, the error is not descriptive of which model failed, you only see:

rake aborted!
ActiveRecord::ReadOnlyRecord: ActiveRecord::ReadOnlyRecord
<PATH_TO_PROJECT>/lib/tasks/example.rake:3:in `block in <top (required)>'
Tasks: TOP => example
(See full trace by running task with --trace)

With my change, you would see:

rake aborted!
ActiveRecord::ReadOnlyRecord: Foo is marked as readonly
<PATH_TO_PROJECT>/lib/tasks/example.rake:3:in `block in <top (required)>'
Tasks: TOP => example
(See full trace by running task with --trace)

[sgrif]

This needs a test.

[senny]

@frankywahl thank you 💛

[frankywahl]

@senny My Pleasure ;)