BaseFormSet.is_multipart() should not only consider the first Form

[mail@…]

I am constructing a FormSet consisting of forms which have fields dynamically added in the init method of the form (to add a FileField only if no initial parameters are given).

However, it shows that BaseFormatSet.is_multipart() only considers the first form of the form set which causes my FormSet to fail if a FileField exists in some forms of the form set, but no in the first one.

Of course, I can solve my problem by implementing is_multipart() by myself but this seems like an ugly workaround. In my opinion, BaseFormatSet.is_multipart() should check all forms of the form set whether any of them contains a field which requires multipart encoding.

[Tim Graham]

I tend to think it's better for you to override it for your use case rather than impose the performance penalty of iterating through all forms on all users. There are similar assumptions in BaseFormSet, like the media property, that assume all forms will be identical.