"Using a model formset in a view" example doesn't handle invalid formset.

[Stephen G Tuggy]

The URL is here: ​https://docs.djangoproject.com/en/dev/topics/forms/modelforms/#using-a-model-formset-in-a-view The 2.2 and 1.8 documentation versions suffer from the same problem (and probably every other version in between).

You will notice that the Method-Based View manage_authors handles the case where request.method == 'POST' and formset.is_valid(), but not the case where request.method == 'POST' and formset is not valid. As a result, newbies (like myself) following this example may not implement this case either. Then, if the data POSTed to this view passes client-side validation but not server-side validation, the user will get an error message:

The view '...' didn't return an HttpResponse object. It returned None instead

See this StackOverflow post, for example: ​https://stackoverflow.com/questions/50202477/the-view-blog-views-post-list-didnt-return-an-httpresponse-object-it-returned?rq=1 And this post: ​https://www.freecodecamp.org/forum/t/didnt-return-an-httpresponse-object-it-returned-none-instead/216155/2

As far as I have been able to determine, the correct code behavior in this situation is pretty much the same as what you do for a GET: Construct a context dictionary, starting with RequestContext, then return the result of rendering the formset once more. One caveat: Make sure your template has a spot to display non-field errors.

Is this correct? Thank you for your attention.

[Mariusz Felisiak]

Thanks for the report, however this code works for me. Please notice that return is outside if ... else block, so it is called even when form is invalid:

if request.method == 'POST':
    ...
else:
    ...
return render(request, 'manage_authors.html', {'formset': formset})

Maybe some indentation issue?

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