[Solved] What is wrong with this FastAPI app code that attempts to add a global dependency? from fastapi import FastAPI, Depends def check_auth(): pass app = FastAPI(dependencies=Depends(check_auth)) | FastAPI

FastAPI - Dependency Injection

What is wrong with this FastAPI app code that attempts to add a global dependency?

from fastapi import FastAPI, Depends

def check_auth():
    pass

app = FastAPI(dependencies=Depends(check_auth))

AThe check_auth function must return a value

BThe dependencies parameter expects a list, not a single Depends instance

CDepends cannot be used with functions without parameters

DGlobal dependencies must be added with @app.dependency decorator

Step-by-Step Solution

Solution:

Step 1: Check dependencies parameter type
The dependencies parameter requires a list of Depends instances, not a single Depends object.
Step 2: Analyze the code
Here, dependencies=Depends(check_auth) passes a single Depends instance instead of a list.
Step 3: Confirm other options
check_auth does not need to return a value, Depends works with parameterless functions, and no such decorator exists.
Final Answer:
The dependencies parameter expects a list, not a single Depends instance -> Option B
Quick Check:
dependencies must be a list [OK]

Quick Trick: dependencies parameter requires a list of Depends [OK]

Common Mistakes:

MISTAKES

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