% ruff rule E501 # Requested at #1909 (review)

line-too-long (E501)

Derived from the pycodestyle linter.

What it does

Checks for lines that exceed the specified maximum character length.

Why is this bad?

Overlong lines can hurt readability. PEP 8, for example, recommends
limiting lines to 79 characters. By default, this rule enforces a limit
of 88 characters for compatibility with Black and the Ruff formatter,
though that limit is configurable via the [line-length] setting.

In the interest of pragmatism, this rule makes a few exceptions when
determining whether a line is overlong. Namely, it:

1. Ignores lines that consist of a single "word" (i.e., without any
   whitespace between its characters).
2. Ignores lines that end with a URL, as long as the URL starts before
   the line-length threshold.
3. Ignores line that end with a pragma comment (e.g., # type: ignore
   or # noqa), as long as the pragma comment starts before the
   line-length threshold. That is, a line will not be flagged as
   overlong if a pragma comment causes it to exceed the line length.
   (This behavior aligns with that of the Ruff formatter.)
4. Ignores SPDX license identifiers and copyright notices
   (e.g., # SPDX-License-Identifier: MIT), which are machine-readable
   and should not wrap over multiple lines.

If [lint.pycodestyle.ignore-overlong-task-comments] is true, this rule will
also ignore comments that start with any of the specified [lint.task-tags]
(e.g., # TODO:).

Example

my_function(param1, param2, param3, param4, param5, param6, param7, param8, param9, param10)

Use instead:

my_function(
    param1, param2, param3, param4, param5,
    param6, param7, param8, param9, param10
)

Error suppression

Hint: when suppressing E501 errors within multi-line strings (like
docstrings), the noqa directive should come at the end of the string
(after the closing triple quote), and will apply to the entire string, like
so:

"""Lorem ipsum dolor sit amet.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.
"""  # noqa: E501

Options

• line-length
• lint.task-tags
• lint.pycodestyle.ignore-overlong-task-comments
• lint.pycodestyle.max-line-length