Changing CSV field accessor does not work with auto-detect format

[sleepinggenius2]

NetBox version

v3.4.4

Python version

3.8

Steps to Reproduce

1. Create Region with name = "Foo" and slug = "foo"
2. Navigate to Site Bulk Import
3. Populate Data with:

name,slug,status,region.slug
Bar,bar,active,foo

4. Leave Format as Auto-detect
5. Click Submit button

Expected Behavior

Site is created successfully under the Foo region.

Observed Behavior

A toast error message saying Record 1 region: Object not found: foo appears.

I believe this is due to this if statement being False, so the correct headers are never set:

netbox/netbox/netbox/views/generic/bulk_views.py

Lines 387 to 388 in 93ac0b7

	if form.cleaned_data['format'] == ImportFormatChoices.CSV:
	model_form_kwargs['headers'] = form._csv_headers

When the format is auto-detected here:

netbox/netbox/utilities/forms/forms.py

Lines 187 to 191 in 93685d9

	# Determine the data format
	if self.cleaned_data['format'] == ImportFormatChoices.AUTO:
	format = self._detect_format(data)
	else:
	format = self.cleaned_data['format']

The value for form.cleaned_data['format'] is never updated to reflect the auto-detected format, so it is still ImportFormatChoices.AUTO when checked in the view.

[jeremystretch]

Thanks for tracking this down @sleepinggenius2!