BaseForm._html_output() uses inconsistent formatting for normal row

[A. Lloyd Flanagan]

Steps to reproduce:

1. Create a form with at least one HiddenInput form field.
2. Override a method such as as_p() by calling _html_output() with:
   1. A normal_row parameter containing the string "%(field_name)s"
   2. A row_ender parameter which is *not* the last tag in normal_row
3. Attempt to render the form. This will result in a builtins.KeyError: 'field_name' message.

Under these conditions, BaseForm._html_output() attempts to create a new row to hold the hidden input fields. When it does, it uses normal_row % {..}, but the dictionary does not have the field "field_name" in it. This causes a KeyError. On the other hand, if normal_row ends in a row_ender tag, it doesn't create a new row, and the method succeeds.

[ppYang]

I'll try to create a patch before this weekend.

[Tim Graham]

Did you see the existing ​pull request and the questions on it?

[ppYang]

Replying to timgraham:

Did you see the existing ​pull request and the questions on it?

Sorry, I thought it's unsigned and wasn't aware of wadevries' pull request.

And even worse, I just submitted another ​pull request...

Sorry for bother your guys, I should be more careful.

[Tim Graham <timograham@…>]

In 3f9ec12d9c9eff9a3b1a205d87c7e66587cf9967:

Fixed #23712 -- Fixed KeyError with BaseForm._html_output()