tiangolo/fastapi · error · HTTPException

Item not found, there's only a plumbus here

Error message

Item not found, there's only a plumbus here

What it means

Same 404 HTTPException as error 24 but in the non-Annotated tutorial008d_py310.py. The yield-dependency re-raises InternalError; any item_id other than 'plumbus' returns 404.

Solutions

1. Request GET /items/plumbus.
2. Understand the tutorial's contrast: this variant re-raises InternalError (500) rather than swallowing it.
3. Map InternalError to an HTTPException in the except block if a clean status code is required.

Example fix

// before
if item_id != "plumbus":
    raise HTTPException(status_code=404, detail="Item not found, there's only a plumbus here")
// after
if item_id != "plumbus":
    raise HTTPException(status_code=404, detail=f"Item '{item_id}' not found")

ALLOWED = {'plumbus'}
if item_id not in ALLOWED:
    print('404; portal-gun -> 500')

def is_known_item(item_id: str) -> bool:
    return item_id == 'plumbus'

resp = requests.get(f'http://localhost:8000/items/{item_id}')
if resp.status_code == 404:
    print('unknown id')
elif resp.status_code == 500:
    print('re-raised InternalError')

When it happens

Trigger: GET /items/{item_id} with item_id != 'plumbus' and != 'portal-gun'.

Common situations: Testing the re-raise variant of yield-dependencies. The 404 fires for ordinary unknown ids; the InternalError (500) fires for 'portal-gun'.

Related errors

• Item not found, there's only a plumbus here
• Item not found, there's only a plumbus here
• Item not found, there's only a plumbus here
• Hero not found
• Hero not found

AI-assisted analysis of tiangolo/fastapi@3e8d1526d8 (2026-08-11). Data as JSON: /api/errors/48a554ee92d6b27f. Report an issue: GitHub.

Appendix: source

Thrown at docs_src/dependencies/tutorial008d_py310.py:25

    pass


def get_username():
    try:
        yield "Rick"
    except InternalError:
        print("We don't swallow the internal error here, we raise again 😎")
        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: str = Depends(get_username)):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(
            status_code=404, detail="Item not found, there's only a plumbus here"
        )
    return item_id

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