title: Django's ClearableFileInput widget doesn't pass initial ("Currently") value on submit
body: <p>My basic goal is to create a form (using <code>ModelForm</code>) prefilled with data from an existing database object, allow a user to modify those data, then save the submitted form as a <em>new</em> object.  (Sort of a "Copy" then "Paste With Modifications" setup.)  This works fine except with File Fields and the ClearableFileInput widget.</p>
  
  <p>The answers to questions like <a href="https://stackoverflow.com/questions/4358356/django-forms-filefield-initial-field">this</a>, <a href="https://stackoverflow.com/questions/3680603/does-django-repopulate-file-fields-on-form-error">this</a>, and <a href="https://stackoverflow.com/questions/4814104/how-to-pass-initial-value-of-filefield-to-formset-in-django">this</a> make it clear that file fields can't and shouldn't be populated with an initial value.</p>
  
  <p>The Django docs, however, on the <a href="https://docs.djangoproject.com/en/dev/ref/forms/widgets/#clearablefileinput" rel="nofollow noreferrer">ClearableFileInput</a> widget say:</p>
  
  <blockquote>
    <p>File upload input: <code>&lt;input type='file' ...&gt;</code>, with an additional checkbox input to clear the field's value, if the field is not required and has <strong><em>initial</em></strong> data.</p>
  </blockquote>
  
  <p>(A bit confusing already, but I assume Django's referring to the <em>model</em> field having an initial value, whereas the <code>&lt;input type='file' ...&gt;</code> field is still blank?)</p>
  
  <p>So if I use either this method:</p>
  
  <pre><code>&gt;&gt;&gt; obj = Foo.objects.get(pk=1)
  &gt;&gt;&gt; obj.fooFile.name
  u'files/foo1.txt'
  &gt;&gt;&gt; f = FooForm(instance=obj)
  </code></pre>
  
  <p>or this method:</p>
  
  <pre><code>f = FooForm(initial={'fooFile':Foo.objects.get(pk=1).fooFile})
  </code></pre>
  
  <p>to instantiate my form, the ClearableFileInput widget displays:</p>
  
  <p><a href="http://phagesdb.org/static/formDisplay.png" rel="nofollow noreferrer">Currently with clearing checkbox, Change... input http://phagesdb.org/static/formDisplay.png</a></p>
  
  <p>When the user submits the form without changing this field, however, the value from the "Currently" line seems to be totally lost to Django.  It doesn't appear to be in either <code>request.POST</code> or <code>form.cleaned_data</code>.  When I call <code>.is_valid()</code> and then <code>.save()</code> on my bound ModelForm, the file field ends up blank in the new object.</p>
  
  <p>So:</p>
  
  <ol>
  <li><p>Does the ClearableFileInput widget pass the "Currently" value or not?  If not, isn't the ClearableFileInput widget misleading and/or of very limited use?  I'd assume that the value returned would be the value in "Currently..." unless I use the "Change..." input.</p></li>
  <li><p>How can I capture that value so it appears in my new object when I call <code>.save()</code>?  (Remember that I can't use <code>f = FooForm(request.POST, request.FILES, instance=obj)</code> because I want a new object, not a modified object.)</p></li>
  </ol>