Summary

The docs for E501 states that "a line will not be flagged as overlong if a pragma comment causes it to exceed the line length."

This works if the comment is # noqa, but seems to fail if there's any other preceding # (with some exceptions for # type: ignore, see below).

Reproducible with source:

def foo(arg=True):... ## noqa: FBT002

and settings:

{
  "line-length": 35,
  "lint": {
    "select": [
      "E501",
      "FBT"
    ]
  },
  "format": {}
}

The practical real-world use-case for this is when multiple linting tools and ignore comments are used, e.g. adding # noqa here where the line was previously not too long will cause a violation (but should not):

# numpydoc ignore=PR01  # noqa: FBT002

Interestingly, the # type: ignore case is handled properly, and does not cause a violation:

# type: ignore  # noqa: FBT002

Version

ruff v0.11.12 (using the ruff playground)

EDIT: For clarity:

This line is not too long:

def foo(arg=True):... #

But this line is:

def foo(arg=True):... ## noqa: FBT002

But, simply adding # noqa: FBT002 should not cause the line to be too long.