circular-dependency

Flask MVC with Circular Dependency (dependency injection?)

Flask MVC with Circular Dependency (dependency injection?) Question: I’m trying to create models to form the mvc in flask but it’s marked as a circular dependency (db in init), I even removed the models to test and put them in for the controllers to use the bank, but the result was the same, what could …

Total answers: 1

Does this design represent circular dependency?

Does this design represent circular dependency? Question: Imagine this example (that may be run without any errors): from random import uniform class Car: def __init__(self, position): self.position = position self.sensor = Sensor(id, self) class Sensor: def __init__(self, id, carrier_car): self.id = id self.position = self.compute_position(carrier_car) def compute_position(self, carrier_car): return [carrier_car.position[0] + uniform(1,3), carrier_car.position[0] + uniform(2,4)] …

Total answers: 1

Using typeguard decorator: @typechecked in Python, whilst evading circular imports?

Using typeguard decorator: @typechecked in Python, whilst evading circular imports? Question: Context To prevent circular imports in Python when using type-hints, one can use the following construct: # controllers.py from __future__ import annotations from typing import TYPE_CHECKING if TYPE_CHECKING: from models import Book class BookController: def __init__(self, book: "Book") -> None: self.book = book Where …

Total answers: 2

FastAPI / Pydantic circular references in separate files

FastAPI / Pydantic circular references in separate files Question: I would love to use a schema that looks something like the following in FastAPI: from __future__ import annotations from typing import List from pydantic import BaseModel class Project(BaseModel): members: List[User] class User(BaseModel): projects: List[Project] Project.update_forward_refs() but in order to keep my project structure clean, I …

Total answers: 4

Python program importing itself

Python program importing itself Question: I made a file named challenge.py with this code in it: import challenge def main(): print(‘Circular much…’) challenge.main() From this I was expecting python to raise an error due to the circular import of importing the file which is running but I found that on python 3.7 & 3.8 this …

Total answers: 4

Why do circular imports seemingly work further up in the call stack but then raise an ImportError further down?

Why do circular imports seemingly work further up in the call stack but then raise an ImportError further down? Question: I’m getting this error Traceback (most recent call last): File "/Users/alex/dev/runswift/utils/sim2014/simulator.py", line 3, in <module> from world import World File "/Users/alex/dev/runswift/utils/sim2014/world.py", line 2, in <module> from entities.field import Field File "/Users/alex/dev/runswift/utils/sim2014/entities/field.py", line 2, in <module> …

Total answers: 9

How to avoid circular imports in Python?

How to avoid circular imports in Python? Question: I know the issue of circular imports in python has come up many times before and I have read these discussions. The comment that is made repeatedly in these discussions is that a circular import is a sign of a bad design and the code should be …

Total answers: 3

Circular import dependency in Python

Circular import dependency in Python Question: Let’s say I have the following directory structure: a __init__.py b __init__.py c __init__.py c_file.py d __init__.py d_file.py In the a package’s __init__.py, the c package is imported. But c_file.py imports a.b.d. The program fails, saying b doesn’t exist when c_file.py tries to import a.b.d. (And it really doesn’t …

Total answers: 7

Circular dependency in Python

Circular dependency in Python Question: I have two files, node.py and path.py, which define two classes, Node and Path, respectively. Up to today, the definition for Path referenced the Node object, and therefore I had done from node.py import * in the path.py file. However, as of today I created a new method for Node …

Total answers: 5

What happens when using mutual or circular (cyclic) imports in Python?

What happens when using mutual or circular (cyclic) imports? Question: In Python, what happens when two modules attempt to import each other? More generally, what happens if multiple modules attempt to import in a cycle? See also What can I do about "ImportError: Cannot import name X" or "AttributeError: … (most likely due to a …

Total answers: 15