Prevent django formset submission if empty

I have a form that I only want users to be able to submit if a field in a formset is filled. This is a dynamic formset in which users can add and remove rows, I want it so that at least one row needs to have an entry in it. However it seems that the formset is able to be submitted even if not valid.

For example if the user does not put an entry for ‘age’ a popup will request that they enter something. This does not occur for ‘diagnosis’

models.py

class Patient(TimeStampedModel):
    patient_id = models.UUIDField(primary_key=True, unique=True, default=uuid.uuid4, editable=False)
    
    age = models.IntegerField("Age")

    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        on_delete=models.SET_NULL)

    
class Diagnosis(TimeStampedModel):
    
    DIAG_CHOICES = [
        (‘heart’, (
                (‘mi’, ‘heart attack’),
                (‘chf’, ‘heart failure’),
            )
        ),
        (‘kidney’, (
                (‘arf’, ‘acute renal failure’),
                (‘crf’, ‘chronic renal failure’),
            )
        ),
        ]
    
    diag_name = models.CharField(
        "diag", max_length=200,
        choices=DIAG_CHOICES, blank=False)

    patient = models.ForeignKey(Patient, on_delete=models.CASCADE)

forms.py

class PatientForm(ModelForm):

    class Meta:
        model = Patient
        fields = ['age']


DiagnosisFormSet = inlineformset_factory(
    Patient, Diagnosis, fields=("diag_name", ), extra=0, min_num=1, validate_min=True)

views.py

class PatientAddView(LoginRequiredMixin,TemplateView):
    model = Patient
    template_name = "../templates/patient/add.html"

    def get(self, *args, **kwargs):
        patient_form = PatientForm
        diagnosis_formset = DiagnosisFormSet(queryset=Diagnosis.objects.none())

        return self.render_to_response({'diagnosis_formset': diagnosis_formset,
                                        'patient_form': patient_form
                                })

    def post(self, *args, **kwargs):
        form = PatientForm(data=self.request.POST)
        diagnosis_formset = DiagnosisFormSet(data=self.request.POST)

        if form.is_valid(): 
            patient_instance = form.save()
            patient_instance.user = self.request.user
            patient_instance.save()

            if diagnosis_formset.is_valid():
                diag_name = diagnosis_formset.save(commit=False)
                for diag in diag_name:
                    diag.patient = patient_instance
                    diag.save()
          

        return redirect(reverse(
                        'patient:treatment_detail',
                        kwargs={"patient_id": patient_instance.patient_id}))

Answer

from django.forms.widgets import Select    

DiagnosisFormSet = inlineformset_factory(
        Patient, Diagnosis, fields=("diag_name",), extra=1, min_num=1, validate_min=True,
        widgets={
            'diag_name': Select(attrs={'required': 'required'}),
        },
    )