Cell content removed on syntax errors with `ruffformat`

[redeboer]

First of all, thanks a ton for fixing support for Ruff since v3.0.0! 🎉

Bug description

It seems that jupyterlab-code-formatter with ruff deletes all content in cells that contain syntax errors.

Reproduce

Running Jupyter Lab in a venv in Python 3.12 with these dependencies

```pip-requirements anyio==4.4.0 argon2-cffi==23.1.0 argon2-cffi-bindings==21.2.0 arrow==1.3.0 asttokens==2.4.1 async-lru==2.0.4 attrs==24.2.0 babel==2.16.0 beautifulsoup4==4.12.3 bleach==6.1.0 certifi==2024.7.4 cffi==1.17.0 charset-normalizer==3.3.2 comm==0.2.2 debugpy==1.8.5 decorator==5.1.1 defusedxml==0.7.1 executing==2.0.1 fastjsonschema==2.20.0 fqdn==1.5.1 h11==0.14.0 httpcore==1.0.5 httpx==0.27.0 idna==3.7 ipykernel==6.29.5 ipython==8.26.0 isoduration==20.11.0 jedi==0.19.1 jinja2==3.1.4 json5==0.9.25 jsonpointer==3.0.0 jsonschema==4.23.0 jsonschema-specifications==2023.12.1 jupyter-client==8.6.2 jupyter-core==5.7.2 jupyter-events==0.10.0 jupyter-lsp==2.2.5 jupyter-server==2.14.2 jupyter-server-terminals==0.5.3 jupyterlab==4.2.4 jupyterlab-code-formatter==3.0.2 jupyterlab-pygments==0.3.0 jupyterlab-server==2.27.3 markupsafe==2.1.5 matplotlib-inline==0.1.7 mistune==3.0.2 nbclient==0.10.0 nbconvert==7.16.4 nbformat==5.10.4 nest-asyncio==1.6.0 notebook-shim==0.2.4 overrides==7.7.0 packaging==24.1 pandocfilters==1.5.1 parso==0.8.4 pexpect==4.9.0 platformdirs==4.2.2 prometheus-client==0.20.0 prompt-toolkit==3.0.47 psutil==6.0.0 ptyprocess==0.7.0 pure-eval==0.2.3 pycparser==2.22 pygments==2.18.0 python-dateutil==2.9.0.post0 python-json-logger==2.0.7 pyyaml==6.0.2 pyzmq==26.1.0 referencing==0.35.1 requests==2.32.3 rfc3339-validator==0.1.4 rfc3986-validator==0.1.1 rpds-py==0.20.0 ruff==0.5.7 send2trash==1.8.3 setuptools==72.2.0 six==1.16.0 sniffio==1.3.1 soupsieve==2.6 stack-data==0.6.3 terminado==0.18.1 tinycss2==1.3.0 tornado==6.4.1 traitlets==5.14.3 types-python-dateutil==2.9.0.20240316 uri-template==1.3.0 urllib3==2.2.2 wcwidth==0.2.13 webcolors==24.8.0 webencodings==0.5.1 websocket-client==1.8.0 ```

and using these minimal settings

{
  "preferences": {
    "default_formatter": {
      "python": ["ruffformat"]
    }
  }
}

Context

• Extension version: 3.0.2
• Operating System and its version: Ubuntu 22.04

[devmcp]

Not sure if it's the same issue, or related, but jupyterlab-code-formatter with ruff also deletes all content in cells that contain non-standard characters. E.g.

print("°")

gets deleted

[redeboer]

Works okay for me. (Same dependencies as in issue description.)

[harrylojames]

Just to chime in also seeing this issue

Not sure if it's the same issue, or related, but jupyterlab-code-formatter with ruff also deletes all content in cells that contain non-standard characters. E.g.

print("°")

gets deleted

[krassowski]

It seems like the code checks whether the command line formatter wrote to stderr to determine if it cannot handle the input:

https://github.com/jupyterlab-contrib/jupyterlab_code_formatter/blob/9f5bec93ffcdb8f74c66b05a3557a6931d8daa39/jupyterlab_code_formatter/formatters.py#L452-L458

But in case of ruff format this probably does not happen and ruff does not return output to neither standard output nor error. I think it should also check the exit code (https://docs.astral.sh/ruff/formatter/#exit-codes). For backward compatibility with other instances/sub-classes of CommandLineFormatter maybe checking the exit code should be optional (e.g. toggled by class property) and for now default to False but changed to True in ruff format.

[dlimpid]

Just to chime in also seeing this issue

Not sure if it's the same issue, or related, but jupyterlab-code-formatter with ruff also deletes all content in cells that contain non-standard characters. E.g.

print("°")

gets deleted

Same to me. When I used @jbwhit's solution there was the same error, that cells containing non-ascii characters were not formatted. For me adding encoding="utf-8" in the subprocess.run() call would fix it.

[yt87]

An exception is required in order to pop up the Jupyterlab Code Formatter Error dialog. Black raises InvalidInput when black.format_str fails. My quick and dirty solution is:

1. Remove quiet option in RuffFormatFormatter.
2. Replace lines 454and 455 by:

   raise ValueError(process.stdin)
   return code

   I think a proper solution would be to subclass CommandLineFormatter overriding format_code.