FastAPI 0.87.0 (and in particular starlette 0.21.0) broke query string parsing in TestClient (starlette 0.22.0 fixes it!)

[andreagrandi]

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Example Code

from fastapi import FastAPI

Description

We have a test that does something like this:

now = utc_datetime()
url = client.app.url_path_for("balances")
start_date = now - timedelta(minutes=1)
start_date_param = urlencode({"start_date": start_date.isoformat()})
end_date_param = urlencode({"end_date": now.isoformat()})
response = client.get(url + f"?{start_date_param}&{end_date_param}")

With FastAPI 0.86 everything works. Starting from 0.87 (which uses starlette 0.21.0) our endpoint errors with:

{'error': {'code': 'validation_error', 'message': 'Validation Error', 'errors': [{'attribute': 'query -> start_date', 'code': 'value_error.datetime', 'message': 'invalid datetime format', 'ctx': None}, {'attribute': 'query -> end_date', 'code': 'value_error.datetime', 'message': 'invalid datetime format', 'ctx': None}]}}

If I force the installation of starlette 0.22.0 and rerun the test, everything works. This is a known bug of starlette 0.21.0 and it has been fixed in 0.22.0:

• https://github.com/encode/starlette/pull/1953/files
• https://github.com/encode/starlette/releases/tag/0.22.0

Solution

Bump starlette version in FastAPI to 0.22.0

Note

I can make this small PR with the update as soon as you confirm/acknowledge this issue.

Operating System

macOS

Operating System Details

No response

FastAPI Version

0.87.0

Python Version

3.10.0

Additional Context

No response

[TheJumpyWizard]

There's a PR up for this now actually

[slafs]

The PR is #5659
and this issue is then, most likely, a duplicate of #5646.

[andreagrandi]

Thanks everyone for the feedback. It seems a duplicate of #5646 yes and since there is already a PR to fix this, I closed the issue already. Looking forward to 0.88.0 release 🫶