When the value for the required key is empty an ActionController::ParameterMissing is raised which gets caught by ActionController::Base and turned into a 400 Bad Request reply with a message in the body saying the key is missing, which is misleading.
With these changes, ActionController::EmptyParameter will be raised which ActionController::Base will catch and turn into a 400 Bad Request reply with a message in the body saying the key value is empty.
Many named routes have keys that are required to successfully resolve. If a key is left off like this:
<%= link_to 'user', user_path %>
This will produce an error like this:
No route matches {:action=>"show", :controller=>"users"}
Since we know that the :id is missing, we can add extra debugging information to the error message.
No route matches {:action=>"show", :controller=>"users"} missing required keys: [:id]
This will help new and seasoned developers look closer at their parameters. I've also subclassed the routing error to be clear that this error is a result of attempting to generate a url and not because the user is trying to visit a bad url.
While this may sound trivial this error message is misleading and confuses most developers. The important part isn't what's in the options its's what's missing. Adding this information to the error message will make debugging much more obvious.
This is the sister pull request of https://github.com/rails/journey/pull/44 which will be required to get they missing keys into the correct error message.
Example Development Error in Rails: http://cl.ly/image/3S0T0n1T3421
Currently Rack raises a TypeError when it encounters a malformed or
ambiguous hash like `foo[]=bar&foo[4]=bar`. Rather than pass this
through to the application this commit captures the exception and
re-raises it using a new ActionController::BadRequest exception.
The new ActionController::BadRequest exception returns a 400 error
instead of the 500 error that would've been returned by the original
TypeError. This allows exception notification libraries to ignore
these errors if so desired.
Closes#3051
