Import/startup performance improvements

src/pretix/helpers/countries.py

@@ -1,6 +1,7 @@
 from django.core.cache import cache
 from django.utils.translation import get_language
 from django_countries import Countries
+from django_countries.fields import CountryField
 
 
 class CachedCountries(Countries):
@@ -27,3 +28,24 @@ class CachedCountries(Countries):
         self._cached_lists[cache_key] = val
         cache.set(cache_key, val, 3600 * 24 * 30)
         yield from val
+
+
+class FastCountryField(CountryField):
+    def __init__(self, *args, **kwargs):
+        kwargs.setdefault("countries", CachedCountries)
+        super().__init__(*args, **kwargs)
+
+    def check(self, **kwargs):
+        # Disable _check_choices since it would require sorting all country names at every import of this field,
+        # which taskes 1-2 seconds
+        return [
+            *self._check_field_name(),
+            # *self._check_choices(),
+            *self._check_db_index(),
+            *self._check_null_allowed_for_primary_keys(),
+            *self._check_backend_specific_checks(**kwargs),
+            *self._check_validators(),
+            *self._check_deprecation_details(),
+            *self._check_multiple(),
+            *self._check_max_length_attribute(**kwargs),
+        ]