ModelSerializer not generating validators for constraints · Issue #7173 · encode/django-rest-framework (original) (raw)

Replacing unique_together on a model with UniqueConstraint constraint (as per Django docs) results in .is_valid() returning True (and an IntegrityError exception being thrown when a call to .save() follows (or 500 Internal Server Error when using API)) rather than .is_valid() returning False (or 400 Bad Request when using API) when uniqueness is violated.

>>># The following is the behavior when using unique_together
>>> data = {'f1': 'bar', 'f2': 1}
>>> s = FooSerializer(data=data)
>>> if s.is_valid():
...     s.save()
...
<Foo: Foo object (1)>
>>> del s
>>> s = FooSerializer(data=data)
>>> if s.is_valid():
...     s.save()
...
>>>

When using, e.g., the browsable API, this results in a 400 Bad Request.

>>># The following is the behavior when using UniqueConstraint
>>> data = {'f1': 'bar', 'f2': 1}
>>> s = FooSerializer(data=data)
>>> if s.is_valid():
...     s.save()
...
<Foo: Foo object (1)>
>>> del s
>>> s = FooSerializer(data=data)
>>> if s.is_valid():
...     s.save()
...
Traceback (most recent call last):
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/sqlite3/base.py", line 383, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.IntegrityError: UNIQUE constraint failed: app_foo.f1, app_foo.f2

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 2, in <module>
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/rest_framework/serializers.py", line 212, in save
    self.instance = self.create(validated_data)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/rest_framework/serializers.py", line 948, in create
    instance = ModelClass._default_manager.create(**validated_data)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/query.py", line 422, in create
    obj.save(force_insert=True, using=self.db)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/base.py", line 741, in save
    force_update=force_update, update_fields=update_fields)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/base.py", line 779, in save_base
    force_update, using, update_fields,
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/base.py", line 870, in _save_table
    result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/base.py", line 908, in _do_insert
    using=using, raw=raw)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/query.py", line 1186, in _insert
    return query.get_compiler(using=using).execute_sql(return_id)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/models/sql/compiler.py", line 1368,
in execute_sql
    cursor.execute(sql, params)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/utils.py", line 99, in execute
    return super().execute(sql, params)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/utils.py", line 67, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/utils.py", line 76, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/home/noone/miniconda3/envs/unique_constraint_sample/lib/python3.7/site-packages/django/db/backends/sqlite3/base.py", line 383, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.IntegrityError: UNIQUE constraint failed: app_foo.f1, app_foo.f2
>>>

When using, e.g., the browsable API, this results in a 500 Internal Server Error.