from django.db import models, IntegrityError

class MyModel(models.Model):
    def save(self):
        """Auto-populate an empty slug field from the MyModel name and
        if it conflicts with an existing slug then append a number and try
        saving again.
        """
        import re
        from django.template.defaultfilters import slugify
        
        if not self.slug:
            self.slug = slugify(self.name)  # Where self.name is the field used for 'pre-populate from'
        
        while True:
            try:
                super(MyModel, self).save()
            # Assuming the IntegrityError is due to a slug fight
            except IntegrityError:
                match_obj = re.match(r'^(.*)-(\d+)$', self.slug)
                if match_obj:
                    next_int = int(match_obj.group(2)) + 1
                    self.slug = match_obj.group(1) + '-' + str(next_int)
                else:
                    self.slug += '-2'
            else:
                break