Silent errors on invalid form submissions

[Matt Giuca]

At least one form fails silently if invalid form data is passed. This could be an idiom we're using but I don't really like it. I tried adding a field and it took me a very long time to discover why the validator wasn't working.

In the New Enrolments form:
http://ivle.localhost/subjects/ivle-102/2009/2/+enrolments/+new

Try adding (with Firebug) a new text field with a funny name, e.g., "foo". Now if you click Enrol, the page will refresh with no errors, as if nothing had happened.

Internally, in ivle/webapp/admin/subject.py, something is afoot! If you get an error validating, say, the "user" field, then the error object you get back will be something like {'user': 'User does not exist'}. This displays properly because our error reporting (in ivle/webapp/admin/templates/enrol.html) is:

<span py:if="'user' in errors" class="form_error">${errors.user}</span>

However, if the error is not with a particular field, but with the form itself, then the error object you get back will be u"The input field 'role' was not expected." (not a dictionary at all, but a string).

I think this error should be displayed somewhere, not just ignored. I can fix it in this particular instance, but I need to know if this is systemic or just an isolated case. ???

[William Grant (wgrant)]

New forms that I've added do not suffer from this problem. Anything deriving from BaseFormView just needs to have something like this in the template:

<div class="submit form_error" py:if="defined('error_value')" py:content="error_value" />