Question

Hi I would like to understand how are the error messages displayed in ruby on rails, more importantly how is the order determined in which the error messages are displayed on the page.

Thanks for your time.

Answer 1

Most common way to display errors is to use helper error_messages:

<%= f.error_messages %>

As far as I know it adds some html tags to error messages that are stored in @my_object.errors hash. Error messages are ordered hash and they are in order that your validations are specified in model (at least it works like this in my applications). You can read more about Errors class here.

Since error_messages are just a helper, you can write your own helper to display error messages.