Bug: Breaking change in new release of Starlette

[miguescri]

Yesterday, Starlette 0.14.1 was released, which removes UJSONResponse. As a result,

fastapi/fastapi/responses.py

Line 10 in b53c443

from starlette.responses import UJSONResponse # noqa

breaks on start-up.

[ycd]

Here is the related PR #2335

[miguescri]

Thank you for the pointer @ycd .

I'll keep the issue open until the PR merges, for reference for users whose servers break (like mine did).

[mezhaka]

What's the smartest thing to do here?
I use conda to create my environment and I have currently pinned starlette==0.13.8, which seems to help.

[Kludex]

@mezhaka Not importing starlette directly on your requirements 🤔

[miguescri]

Yes, until #2335 merges, the Starlette version needs to be pinned to <0.14.1 if you have it in your requirements.

@Kludex , for most people that will do. But it is worth noting that may not be an option if you directly use some of Startlette's elements and need to have an updated version. Keep in mind that right now FastAPI installs by default Starlette 0.13.6, which is 4 releases behind master.

[mezhaka]

@Kludex @miguescri I did not have explicit Starlette in my environment and this way the app was broken. As I have added it explicitly -- it runs.

[Mause]

Which package manager are you using? If you don't add an explicit dependency version, it should automatically install a compatible version

[miguescri]

@mezhaka are you using a virtual env or a system wide installation? And are you using a Python package manager or you installed some of the Python packages from your distro's repositories?

[mezhaka]

@Mause @miguescri I use conda. I have an environment.yml file which looks something like this (I've removed some packages):

name: myapp
channels:
  - conda-forge
  - mycompany
dependencies:
  - python~=3.7
  - pymongo~=3.10
  - gunicorn~=20.0
  - uvicorn~=0.11
  - fastapi~=0.60
  - pydantic~=1.6

I then create environments with conda env create -f env.yml, activate it conda env activate myapp, and start my python web app.
As soon as I've added - starlette==0.13.8 to this list -- the error went away.

[ycd]

Btw, i'm still not sure this error is an expected behaviour, because in our pyproject.toml

fastapi/pyproject.toml

Line 35 in 52dd592

"starlette ==0.13.6",

Starlette pinned to the 0.13.6, so it shouldn't be installing the 0.14.1.

[maresb]

I also ran into problems with my Conda environment. FastAPI pins starlette-base to 0.13.6 but starlette itself is unpinned.

I reported it to the feedstock here:
conda-forge/fastapi-feedstock#43

[miguescri]

#2335 has been merged.

[tiangolo]

Thanks for the help here everyone! 👏 🙇

Thanks for reporting back and closing the issue @miguescri 👍

Sorry for the long delay! 🙈 I wanted to personally address each issue/PR and they piled up through time, but now I'm checking each one in order.

[github-actions]

Assuming the original need was handled, this will be automatically closed now. But feel free to add more comments or create new issues or PRs.