Removal of semicolon in notebooks

[peendebak]

One of the default rules in ruff is to remove a trailing semicolon. That is fine for python scripts, for for jupyter notebook this can change the output of the code cells. A screenshot to illustrate:

The removal of the semicolon results in the output of the plt.plot command being displayed. Typically this is not the intention, so a semicolor is used to hide the command output and only the the plotted graph.

Can the ruff default settings be modified to remove semicolons for python files, but not for notebooks?

[dhruvmanila]

I think this might be similar to #6586 where it's only the last expression in a cell where this rule should be disabled. We could probably have a general interface internally to include rules which need not be checked for last expressions in all cells within a Jupyter Notebook.

Until that is supported, you could disable this rule on Jupyter Notebooks like so:

[tool.ruff]
per-file-ignores = { "*.ipynb" = ["E703"] }

https://beta.ruff.rs/docs/rules/useless-semicolon/

[henryiii]

There are several rules that don't apply to notebooks, or apply in a modified form. B018 - A useless expression at the end of a cell is actually not useless, that's how you show the (notebook customized if applicable) display of an object. T20 also usually doesn't apply, notebooks are not library files, but I think it's fine to have to disable that.

Ideally B018 and E703 would learn that when in a cell, they don't apply to the last item in the cell.

[charliermarsh]

Agreed.

[charliermarsh]

We already had to solve this cell-boundaries problem for isort, so should be doable in these cases too.

[s-weigand]

[tool.ruff]
per-file-ignores = { "*.ipynb" = ["E703"] }

Sadly this seems not to be respected by ruff format 😢
Even so, it is not part of the conflicting rules

[dhruvmanila]

(Merging this with a general tracking issue: #8669)

[dhruvmanila]

[tool.ruff]
per-file-ignores = { "*.ipynb" = ["E703"] }

Sadly this seems not to be respected by ruff format 😢 Even so, it is not part of the conflicting rules

@s-weigand Hi, we recently updated the formatter to not remove any trailing semicolon in notebook context: #8590. It'll be available in the next release.