#22260: Custom model field: field.db_type not called for (initial) migration /
docs
wrong? (DurationField)
----------------------------+--------------------
Reporter: blueyed | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: master
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+--------------------
While trying to use the [https://github.com/johnpaulett/django-
durationfield DurationField] with Django 1.7 I have noticed that the field
is silently ignored from being added to the database.
While the initial migration is correct, the lookup for the db field type
fails.
The [https://docs.djangoproject.com/en/dev/howto/custom-model-fields
/#custom-database-types docs state]:
> The db_type() method is called by Django when the framework constructs
the CREATE TABLE statements for your application – that is, when you first
create your tables.
This does not appear to be the case with migrations however, which only
call `field.db_parameters`:
…/django-master/django/db/migrations/executor.py(60)migrate()
58 for migration, backwards in plan:
59 if not backwards:
---> 60 self.apply_migration(migration, fake=fake)
61 else:
62 self.unapply_migration(migration, fake=fake)
…/django-
master/django/db/migrations/executor.py(95)apply_migration()
93 import ipdb; ipdb.set_trace()
94 project_state =
self.loader.graph.project_state((migration.app_label, migration.name),
at_end=False)
---> 95 migration.apply(project_state,
schema_editor)
96 # For replacement migrations, record individual
statuses
97 if migration.replaces:
…/django-master/django/db/migrations/migration.py(97)apply()
95 operation.state_forwards(self.app_label,
new_state)
96 # Run the operation
---> 97 operation.database_forwards(self.app_label,
schema_editor, project_state, new_state)
98 # Switch states
99 project_state = new_state
…/django-
master/django/db/migrations/operations/models.py(28)database_forwards()
26 model = apps.get_model(app_label, self.name)
27 if
router.allow_migrate(schema_editor.connection.alias, model):
---> 28 schema_editor.create_model(model)
29
30 def database_backwards(self, app_label, schema_editor,
from_state, to_state):
…/django-master/django/db/backends/schema.py(191)create_model()
189 for field in model._meta.local_fields:
190 # SQL
--> 191 definition, extra_params = self.column_sql(model,
field)
192 if definition is None:
193 continue
> …/django-master/django/db/backends/schema.py(108)column_sql()
106 """
107 # Get the column's type and use that as the basis of
the SQL
--> 108 db_params =
field.db_parameters(connection=self.connection)
109 sql = db_params['type']
110 params = []
From the initial migration:
> ('runtime',
durationfield.db.models.fields.duration.DurationField(help_text=u'Format:
HH:MM:SS', null=True, verbose_name=u'Playtime')),
Commit [https://github.com/django/django/commit/e5983af e5983af] (from
2012) changed BaseDatabaseSchemaEditor from using `db_type` to
`db_parameters`.
(In commit [https://github.com/django/django/commit/1a9f13d 1a9f13d] the
documentation got improved somehow, but appears to still reflect not the
new/different behavior using migrations).
I have filed an [https://github.com/johnpaulett/django-
durationfield/issues/15 issue for django-durationfield].
The source for the custom model field: [https://github.com/johnpaulett
/django-
durationfield/blob/master/durationfield/db/models/fields/duration.py
duration.py].
Let me know if I should provide a simple test case / test app.
While at it, I think that there should have been a warning or assertion
being triggered in this case. I have seen that the code considers this
case to be a m2m field (or something similar), but those might look
different at that point - and an assertion could be made there.
--
Ticket URL: <https://code.djangoproject.com/ticket/22260>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-updates+unsubscr...@googlegroups.com.
To post to this group, send email to django-updates@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/050.90c604fb03ce0537d248fc8f8dd0c724%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
