id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
27037	'required' attribute on prefilled ClearableFileInput prevents valid form submissions	Matt Westcott	nobody	"The addition of the `required` HTML attribute on required form fields (#22383) does not handle the situation where a `ClearableFileInput` is pre-populated with an initial value (causing it to display the ""Currently: foo.txt"" text alongside an empty `<input type=""file"">` field) and submitted without selecting a new file. According to Django's validation logic this is a valid form submission, as the field is considered non-empty. However, the browser-side validation doesn't know about this nuance - at the HTML level, the `<input type=""file"">` element ''is'' an empty field, and has the `required` attribute set, causing it to fail validation.

This breaks the conventional ModelForm-based 'edit' view pattern, on any model that has a required FileField. For example:

{{{
# models.py
class Document(models.Model):
    title = models.CharField(max_length=255)
    file = models.FileField()

# forms.py
class DocumentForm(forms.ModelForm):
    class Meta:
        model = Document
        fields = ['title', 'file']

# views.py
def edit(request, document_id):
    document = Document.objects.get(id=document_id)

    if request.method == 'POST':
        # ...
        return HttpResponse(""OK"")
    else:
        form = DocumentForm(instance=document)
        return render(request, 'edit.html', {'document': document, 'form': form})

# edit.html
	<form action=""{% url 'edit_document' document.id %}"" method=""POST"">
		{{ form.as_p }}
		<input type=""submit"">
	</form>

# renders as the following, which cannot be submitted as-is: 
<p><label for=""id_file"">File:</label> Currently: <a href=""hello.txt"">hello.txt</a> <br />Change: <input id=""id_file"" name=""file"" type=""file"" required /></p>
}}}

I suggest that ClearableFileInput should discard the `required` attribute whenever an initial value exists, in much the same way that CheckboxSelectMultiple does: https://github.com/django/django/blob/35225e2ade08ea32e36a994cd4ff90842c599e20/django/forms/widgets.py#L797-L799"	Bug	closed	Forms	1.10	Release blocker	fixed			Ready for checkin	1	0	0	0	0	0