django, mypy : 查询集，选择错误：不兼容的类型

问题描述

我们有：

在models.py中

class Language(models.IntegerChoices):
    en = 1
    ru = 2

class Translation(models.Model):
    language_id = models.PositiveIntegerField(choices=Language.choices)
    mnemonic = models.CharField(max_length=255)
    translation = models.CharField(max_length=255)

1. 在 serializers.py 中

    66    def get_translations(self,obj):
    67        language: int = self.initial_data.get('language') or settings.SERVER['current_language_id']
    68        common_public = Translation.objects.filter(language_id=language).exclude(mnemonic__startswith='dictionary')

当我通过 mypy 检查它时：

resources/serializers.py:67: 错误：赋值中的类型不兼容（表达式类型为“Union[Any,object]”，变量类型为“int”）

2. 如果在 serializers.py 中

    66    def get_translations(self,obj):
    67        language: Union[Any,object] = self.initial_data.get('language') or settings.SERVER['current_language_id']
    68        common_public = Translation.objects.filter(language_id=language).exclude(mnemonic__startswith='dictionary')

通过mypy检查：

resources/serializers.py:68: 错误：查找 'language_id' 的类型不兼容：（得到“Union[Any,object]”，预期为“Union[str,int]”）

3)

66    def get_translations(self,obj):
67        language: Union[str,int] = self.initial_data.get('language') or settings.SERVER['current_language_id']
68        common_public = Translation.objects.filter(language_id=language).exclude(mnemonic__startswith='dictionary')

检查一下：

resources/serializers.py:67: 错误：赋值中的类型不兼容（表达式类型为“Union[Any,object]”，变量类型为“Union[str,int]”）

怎么了？

mypy.ini:

[mypy]
python_version = 3.8
mypy_path = ./stubs

check_untyped_defs = True
disallow_any_generics = True
disallow_untyped_calls = True
disallow_untyped_decorators = True
ignore_errors = False
ignore_missing_imports = True
implicit_reexport = False
strict_optional = True
strict_equality = True
no_implicit_optional = True
warn_unused_ignores = True
warn_redundant_casts = True
warn_unused_configs = True
warn_unreachable = True
warn_no_return = True
plugins = mypy_django_plugin.main

[mypy.plugins.django-stubs]
django_settings_module = server.settings

[mypy-*.migrations.*]
ignore_errors = True

解决方法

错误出现在 settings.SERVER['current_language_id']

正确的方法：

getattr(settings.SERVER,'current_language_id')

现在mypy好了