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

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:

jupyterlab_code_formatter/jupyterlab_code_formatter/formatters.py

Lines 452 to 458 in 9f5bec9

	if process.stderr:
	logger.info(f"An error with {self.command[0]} has occurred:")
	logger.info(process.stderr)
	return code
	else:
	return process.stdout

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.