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DJ012 is not raised when a parent class, that inherits from django.Model, is in a different file.
Search keywords
"DJ012", "django Model"
Ruff Version
0.5.7
Config
Part of pyproject.toml
[tool.poetry.group.dev.dependencies]
ruff = "0.5.7"
[tool.ruff]
line-length = 120
extend-exclude = ["venv", "stubs"]
[tool.ruff.lint]
select = ["ALL"]
unfixable = ["ERA001", "COM819"] # remove comment out code lines
ignore = [
"Q", # flake8-quotes
"D100", # undocumented-public-module Missing docstring in public module
"D101", # undocumented-public-class "Missing" # docstring in public class
"D102", # undocumented-public-method Missing docstring "in" # public method
"D103", # undocumented-public-function Missing docstring in "public" # function
"D104", # undocumented-public-package Missing docstring in public package "🛠"
"D105", # undocumented-magic-method Missing docstring in magic method
"D106", # # undocumented-public-nested-class Missing docstring in public nested class
"D107", # # undocumented-public-init Missing docstring in __init__
"ANN101", # missing-type-self
"TD003", # missing-todo-link missing issue link on the line following this TODO
"TD002", # missing-todo-author missing author in TODO; try: `# TODO(<author_name>): ...` or `# TODO @<author_name>: ...`Ruff
"S101", # assert Use of assert detected
"ANN002", # missing-type-args Missing type annotation for *{name}
"ANN003", # missing-type-kwargs Missing type annotation for **{name}
"RUF001", # ambiguous-unicode-character-string String contains ambiguous {}. Did you mean {}? Может на русскую "с" в комменте ругаться
"RUF003", # ambiguous-unicode-character-comment
"SLF001", # private-member-access Private member accessed: {access} | учитывая, что в Django постоянно дергаем _Meta моделей и поля в духе _prefetched_objects_cache и т.д.
"FA100", # future-rewritable-type-annotation Missing from __future__ import annotations, but uses {name}
"FA102", # future-required-type-annotation Missing from __future__ import annotations, but uses
"DJ001", # django-nullable-model-string-field Avoid using null=True on string-based fields such as
"PGH004", # Use specific rule codes when using `noqa`
"TRY003", # Avoid specifying long messages outside the exception class
"EM102", # Exception must not use an f-string literal, assign to variable first
"RUF002", # Docstring contains ambiguous `у` (CYRILLIC SMALL LETTER U). Did you mean `y` (LATIN SMALL LETTER Y)?
"FBT001", # Boolean-typed positional argument in function definition
"FBT002", # Boolean default positional argument in function definition
"ANN204", # Missing return type annotation for special method `__init__`
]
[tool.ruff.lint.flake8-annotations]
mypy-init-return = true # ANN204 | checkers often allow you to omit the return type annotation for __init__ methods, as long as at least one argument has a type annotation
[tool.ruff.lint.isort]
force-wrap-aliases = true
combine-as-imports = true
Bug Description
DJ012 checking doesnt work properly. If a model with incorrect order of attributes and methods inherits from a Django model-based class, located in a separate file, the error is not raised.
Details
Proper behavior
With this code, ruff works correctly: the error is raised:
from django.db import models
class MyModel(models.Model):
name = models.CharField(
max_length=500,
verbose_name="Название",
default="",
)
def __str__(self) -> str:
return "self.name"
class Meta:
verbose_name = "Модель"
verbose_name_plural = "Модели"
Ruff output
[N] (venv) valera@t-t14 ~/P/a/s/backend (NATNP-3701)> ruff check src/my_subsystem/models/my_model.py
warning: `one-blank-line-before-class` (D203) and `no-blank-line-before-class` (D211) are incompatible. Ignoring `one-blank-line-before-class`.
warning: `multi-line-summary-first-line` (D212) and `multi-line-summary-second-line` (D213) are incompatible. Ignoring `multi-line-summary-second-line`.
src/my_subsystem/models/my_model.py:14:5: DJ012 Order of model's inner classes, methods, and fields does not follow the Django Style Guide: `Meta` class should come before `__str__` method
|
12 | return "self.name"
13 |
14 | class Meta:
| _____^
15 | | verbose_name = "Модель"
16 | | verbose_name_plural = "Модели"
| |___________________________________^ DJ012
|
Found 1 error.
Another correct behavior
Here i added ParentModel. Now MyModel inherits from it. The error is still present. Everything works correctly.
from django.db import models
class ParentModel(models.Model):
text = models.CharField(max_length=100)
class Meta:
abstract = True
def __str__(self) -> str:
return super().__str__()
class MyModel(ParentModel):
name = models.CharField(
max_length=500,
verbose_name="Название",
default="",
)
def __str__(self) -> str:
return "self.name"
class Meta:
verbose_name = "Модель"
verbose_name_plural = "Модели"
Ruff-output
[N] (venv) valera@t-t14 ~/P/a/s/backend (NATNP-3701) [0|1]> ruff check src/my_subsystem/models/my_model.py
warning: `one-blank-line-before-class` (D203) and `no-blank-line-before-class` (D211) are incompatible. Ignoring `one-blank-line-before-class`.
warning: `multi-line-summary-first-line` (D212) and `multi-line-summary-second-line` (D213) are incompatible. Ignoring `multi-line-summary-second-line`.
src/my_subsystem/models/my_model.py:24:5: DJ012 Order of model's inner classes, methods, and fields does not follow the Django Style Guide: `Meta` class should come before `__str__` method
|
22 | return "self.name"
23 |
24 | class Meta:
| _____^
25 | | verbose_name = "Модель"
26 | | verbose_name_plural = "Модели"
| |___________________________________^ DJ012
|
Found 1 error.
[I] (venv) valera@t-t14 ~/P/a/s/backend (NATNP-3701) [0|1]>
Bug
The only change made was moving ParentModel to a separate file (in the same directory as my_model.py). After this change, the error disappeared.
parent_model.py
from django.db import models
from django.db.models import Model
class ParentModel(Model):
text = models.CharField(max_length=100)
class Meta:
abstract = True
def __str__(self) -> str:
return super().__str__()
my_model.py
from django.db import models
from my_subsystem.models.parent import ParentModel
class MyModel(ParentModel):
name = models.CharField(
max_length=500,
verbose_name="Название",
default="",
)
def __str__(self) -> str:
return "self.name"
class Meta:
verbose_name = "Модель"
verbose_name_plural = "Модели"
Ruff output
[N] (venv) valera@t-t14 ~/P/a/s/backend (NATNP-3701) [0|1]> ruff check src/my_subsystem/models/my_model.py
warning: `one-blank-line-before-class` (D203) and `no-blank-line-before-class` (D211) are incompatible. Ignoring `one-blank-line-before-class`.
warning: `multi-line-summary-first-line` (D212) and `multi-line-summary-second-line` (D213) are incompatible. Ignoring `multi-line-summary-second-line`.
All checks passed!
@charliermarsh Hey, can I ask more about why this is related to multifile limitation? I have this class:
class MyModel(models.Model):
...
def __str__(self):
return ...
class Meta:
verbose_name = "..."
DJ012 detects the issue successfully. If I replace the base class, it fails to find the issue, even though there is nothing related to the base class itself - the issue is right there on the class, contained in a single file.
@ulgens
Can you share a full code example because I'm unable to reproduce the issue in the playground; https://play.ruff.rs/bdf4614f-9c68-4943-947f-05a1cf2a16f2
@MichaReiser https://play.ruff.rs/6c3fa123-7dea-4830-a465-da719b39ef37
I hope it demonstrates one aspect of the issue. Even though BaseModel is defined in the same file, ruff fails to detect DJ012.
In my case, BaseModel is defined in a different file but my point was that there is no need to check that other file. DJ012 doesn't even make sense in multifile context.
Thanks. Yes, that helps to understand the issue. Ruff doesn't perform any alias analysis for this rule (analysing if a variable x points to BaseModel). That's why it isn't picked up. Ruff supports this in very limited way for some rules but it isn't very consistent about it. The solution here is, as well, a more powerful analysis engine which we are building in ty and plan to make use of in Ruff in the future.
Can you tell me more about why you're aliasing BaseModel?
@MichaReiser This is the BaseModel: https://github.com/ulgens/django-blasphemy/blob/50805be4727e88aebbabc4c521604dcee232a9ab/src/core/db/models.py#L35 I'm not actually aliasing it, it's a base class that provides common functionalities to all models in the project.
Ruff doesn't perform any alias analysis for this rule
I'm a bit lost about this. What I expect here is that any rule defined for a model class should check all classes that inherit from django.db.models.Model and not care about how they are defined.
You're aliasing BaseModel here
BaseModel = models.Model
The rule works as expected if you use
class MyModel(models.Model):
"""..."""
def __str__(self) -> str:
return "string"
class Meta:
verbose_name = "..."
I'm a bit lost about this. What I expect here is that any rule defined for a model class should check all classes that inherit from django.db.models.Model and not care about how they are defined.
I agree that this is the ideal and we're working towards it. It's just not as "easy" to detect all those cases statically
You're aliasing BaseModel here
That was just a simplified case to demonstrate that the issue is not related to multifile setup, but I still think it shouldn't be relevant.
It's just not as "easy" to detect all those cases statically
I think this is not a "there are many cases that we should find but we can't because it's hard" case. I think the bug here is much simpler (not saying it's easier to solve). Let me try to demonstrate the issue with Python:
Given
from django.db.models import Model
The current implementation checks
Model in MyModel.__bases__
which is not true if a class is not defined as MyModel(models.Model)
The correct way of checking if a class is a Django model should be
import inspect
Model in inspect.getmro(MyModel)
To summarize, the issue here is not
DJ012 is not raised when a parent class, that inherits from django.Model, is in a different file.
It's that DJ rules can't properly detect a model class.