Refactor our migrate command monkeypatching

src/pretix/base/management/commands/makemigrations.py

@@ -32,53 +32,10 @@
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.
 
-"""
-Django, for theoretically very valid reasons, creates migrations for *every single thing*
-we change on a model. Even the `help_text`! This makes sense, as we don't know if any
-database backend unknown to us might actually use this information for its database schema.
-
-However, pretix only supports PostgreSQL, MySQL, MariaDB and SQLite and we can be pretty
-certain that some changes to models will never require a change to the database. In this case,
-not creating a migration for certain changes will save us some performance while applying them
-*and* allow for a cleaner git history. Win-win!
-
-Only caveat is that we need to do some dirty monkeypatching to achieve it...
-"""
 from django.core.management.commands.makemigrations import Command as Parent
-from django.db import models
-from django.db.migrations.operations import models as modelops
-from django_countries.fields import CountryField
+from ._migrations import monkeypatch_migrations
 
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("verbose_name")
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("verbose_name_plural")
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("ordering")
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("get_latest_by")
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("default_manager_name")
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("permissions")
-modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("default_permissions")
-IGNORED_ATTRS = [
-    # (field type, attribute name, banlist of field sub-types)
-    (models.Field, 'verbose_name', []),
-    (models.Field, 'help_text', []),
-    (models.Field, 'validators', []),
-    (models.Field, 'editable', [models.DateField, models.DateTimeField, models.DateField, models.BinaryField]),
-    (models.Field, 'blank', [models.DateField, models.DateTimeField, models.AutoField, models.NullBooleanField,
-                             models.TimeField]),
-    (models.CharField, 'choices', [CountryField])
-]
-
-original_deconstruct = models.Field.deconstruct
-
-
-def new_deconstruct(self):
-    name, path, args, kwargs = original_deconstruct(self)
-    for ftype, attr, banlist in IGNORED_ATTRS:
-        if isinstance(self, ftype) and not any(isinstance(self, ft) for ft in banlist):
-            kwargs.pop(attr, None)
-    return name, path, args, kwargs
-
-
-models.Field.deconstruct = new_deconstruct
+monkeypatch_migrations()
 
 
 class Command(Parent):