Bug: SQLFORM.accepts() breaks formstyle when widgets are defined

[tim.n...@conted.ox.ac.uk]

I'm using a custom formstyle to apply bootstrap3 to my forms (a modified copy of the built-in bootstrap3_inline).  Importantly, it adds the form-control class to each input.

This works fine, until you define a widget for a field, and have it fail validation.

db.define_table('test',

    Field('one', 'string', requires=IS_MATCH('STUFF')),

    Field('two', 'string', requires=IS_MATCH('STUFF'), widget=SQLFORM.widgets.string.widget),    

    )

def index():

    form = SQLFORM(db.test, formstyle='bootstrap3_inline')  

    form.process()

    

    return dict(form=form)

Despite being identical fields, with identical widgets, field two loses its formatting.  Why?  Because of the following code at the bottom of SQLFORM.accepts()

elif (not ret) and (not auch):

    # auch is true when user tries to delete a record

    # that does not pass validation, yet it should be deleted

    for fieldname in self.fields:

        field = (self.table[fieldname]

                 if fieldname in self.table.fields

                 else self.extra_fields[fieldname])

        ### this is a workaround! widgets should always have default not None!

        if not field.widget and field.type.startswith('list:') and \

                not OptionsWidget.has_options(field):

            field.widget = self.widgets.list.widget

        if field.widget and fieldname in request_vars:

            if fieldname in self.request_vars:

                value = self.request_vars[fieldname]

            elif self.record:

                value = self.record[fieldname]

            else:

                value = field.default

            row_id = '%s_%s%s' % (

                self.table, fieldname, SQLFORM.ID_ROW_SUFFIX)

            widget = field.widget(field, value)

            parent = self.field_parent[row_id]

            if parent:

                parent.components = [widget]

                if self.errors.get(fieldname):

                    parent._traverse(False, hideerror)

            self.custom.widget[fieldname] = widget

If a field's widget is defined, it overwrites it, for reasons mysterious to me.  This occurs after the formstyle is applied.

If I remove that source code, or remove the widget between form setup and validation:

def index():

    form = SQLFORM(db.test, formstyle='bootstrap3_inline')  

    db.test.two.widget=None  

    form.process()

    

    return dict(form=form)

Then everything works fine.  

What is the point of that code at the end of accepts(), and is this working as designed?