Simple fix for the CfP proposal progress issue

app/eventyay/cfp/flow.py

@@ -219,14 +219,30 @@ def get_form_initial(self):
         return copy.deepcopy({**initial_data, **previous_data})
 
     def get_form(self, from_storage=False):
-        if self.request.method == 'GET' or from_storage:
+        if self.request.method == 'GET':
+            # For GET requests, use unbound forms with initial data
+            # This correctly displays saved values from the session
             return self.form_class(
-                data=self.get_form_initial() if from_storage else None,
+                data=None,
+                initial=self.get_form_initial(),
+                files=None,
+                **self.get_form_kwargs(),
+            )
+        if from_storage:
+            # For validation checks, create a bound form with session data
+            return self.form_class(
+                data=self.get_form_initial(),
                 initial=self.get_form_initial(),
                 files=self.get_files(),
                 **self.get_form_kwargs(),
             )
-        return self.form_class(data=self.request.POST, files=self.request.FILES, **self.get_form_kwargs())
+        # For POST requests, merge new uploads with existing session files
+        # This allows users to navigate back without losing previously uploaded files
+        session_files = self.get_files() or {}
+        new_files = dict(self.request.FILES.items())
+        # New uploads take precedence over session files
+        files = {**session_files, **new_files}
+        return self.form_class(data=self.request.POST, files=files, **self.get_form_kwargs())
 
     def is_completed(self, request):
         self.request = request
@@ -237,6 +253,11 @@ def get_context_data(self, **kwargs):
         result['form'] = self.get_form()
         previous_data = self.cfp_session.get('data')
         result['submission_title'] = previous_data.get('info', {}).get('title')
+        # Add information about uploaded files for display in templates
+        saved_files = self.cfp_session.get('files', {}).get(self.identifier, {})
+        result['uploaded_files'] = {
+            field: file_dict.get('name') for field, file_dict in saved_files.items()
+        } if saved_files else {}
         return result
 
     def post(self, request):

app/eventyay/cfp/templates/cfp/event/submission_base.html

@@ -49,6 +49,16 @@ <h2>{% block submission_step_title %}{{ title|default:'' }}{% endblock submissio
             </div>
             {% block submission_step_text %}<p>{{ text|rich_text }}</p>{% endblock %}
             {% block inner %}
+                {% if uploaded_files %}
+                    <div class="alert alert-info mb-3">
+                        <i class="fa fa-info-circle"></i> {% translate "Previously uploaded files:" %}
+                        <ul class="mb-0 mt-1">
+                            {% for field_name, filename in uploaded_files.items %}
+                                <li><strong>{{ filename }}</strong> {% translate "(will be preserved if you don't upload a new file)" %}</li>
+                            {% endfor %}
+                        </ul>
+                    </div>
+                {% endif %}
                 {{ form }}
             {% endblock inner %}
             {% block buttons %}