ruff/BREAKING_CHANGES.md

Breaking Changes

0.0.246

multiple-statements-on-one-line-def (E704) was removed (#2773)

This rule was introduced in v0.0.245. However, it turns out that pycodestyle and Flake8 ignore this rule by default, as it is not part of PEP 8. As such, we've removed it from Ruff.

0.0.245

Ruff's public check method was removed (#2709)

Previously, Ruff exposed a check method as a public Rust API. This method was used by few, if any clients, and was not well documented or supported. As such, it has been removed, with the intention of adding a stable public API in the future.

0.0.238

select, extend-select, ignore, and extend-ignore have new semantics (#2312)

Previously, the interplay between select and its related options could lead to unexpected behavior. For example, ruff --select E501 --ignore ALL and ruff --select E501 --extend-ignore ALL behaved differently. (See #2312 for more examples.)

When Ruff determines the enabled rule set, it has to reconcile select and ignore from a variety of sources, including the current pyproject.toml, any inherited pyproject.toml files, and the CLI.

The new semantics are such that Ruff uses the "highest-priority" select as the basis for the rule set, and then applies any extend-select, ignore, and extend-ignore adjustments. CLI options are given higher priority than pyproject.toml options, and the current pyproject.toml file is given higher priority than any inherited pyproject.toml files.

extend-select and extend-ignore are no longer given "top priority"; instead, they merely append to the select and ignore lists, as in Flake8.

This change is largely backwards compatible -- most users should experience no change in behavior. However, as an example of a breaking change, consider the following:

[tool.ruff]
ignore = ["F401"]

Running ruff --select F would previously have enabled all F rules, apart from F401. Now, it will enable all F rules, including F401, as the command line's --select resets the resolution.

remove-six-compat (UP016) has been removed (#2332)

The remove-six-compat rule has been removed. This rule was only useful for one-time Python 2-to-3 upgrades.

0.0.237

--explain, --clean, and --generate-shell-completion are now subcommands (#2190)

--explain, --clean, and --generate-shell-completion are now implemented as subcommands:

ruff .         # Still works! And will always work.
ruff check .   # New! Also works.

ruff --explain E402   # Still works.
ruff rule E402        # New! Also works. (And preferred.)

# Oops! The command has to come first.
ruff --format json --explain E402   # No longer works.
ruff --explain E402 --format json   # Still works!
ruff rule E402   --format json      # Works! (And preferred.)

This change is largely backwards compatible -- most users should experience no change in behavior. However, please note the following exceptions:

• Subcommands will now fail when invoked with unsupported arguments, instead of silently ignoring them. For example, the following will now fail:

  ruff --clean --respect-gitignore
  

  (the clean command doesn't support --respect-gitignore.)

• The semantics of ruff <arg> have changed slightly when <arg> is a valid subcommand. For example, prior to this release, running ruff rule would run ruff over a file or directory called rule. Now, ruff rule would invoke the rule subcommand. This should only impact projects with files or directories named rule, check, explain, clean, or generate-shell-completion.

• Scripts that invoke ruff should supply -- before any positional arguments. (The semantics of ruff -- <arg> have not changed.)

• --explain previously treated --format grouped as a synonym for --format text. This is no longer supported; instead, use --format text.

0.0.226

misplaced-comparison-constant (PLC2201) was deprecated in favor of SIM300 (#1980)

These two rules contain (nearly) identical logic. To deduplicate the rule set, we've upgraded SIM300 to handle a few more cases, and deprecated PLC2201 in favor of SIM300.

0.0.225

@functools.cache rewrites have been moved to a standalone rule (UP033) (#1938)

Previously, UP011 handled both @functools.lru_cache()-to-@functools.lru_cache conversions, and @functools.lru_cache(maxsize=None)-to-@functools.cache conversions. The latter has been moved out to its own rule (UP033). As such, some # noqa: UP011 comments may need to be updated to reflect the change in rule code.

0.0.222

--max-complexity has been removed from the CLI (#1877)

The McCabe plugin's --max-complexity setting has been removed from the CLI, for consistency with the treatment of other, similar settings.

To set the maximum complexity, use the max-complexity property in your pyproject.toml file, like so:

[tool.ruff.mccabe]
max-complexity = 10

0.0.181

Files excluded by .gitignore are now ignored (#1234)

Ruff will now avoid checking files that are excluded by .ignore, .gitignore, .git/info/exclude, and global gitignore files. This behavior is powered by the ignore crate, and is applied in addition to Ruff's built-in exclude system.

To disable this behavior, set respect-gitignore = false in your pyproject.toml file.

Note that hidden files (i.e., files and directories prefixed with a .) are not ignored by default.

0.0.178

Configuration files are now resolved hierarchically (#1190)

pyproject.toml files are now resolved hierarchically, such that for each Python file, we find the first pyproject.toml file in its path, and use that to determine its lint settings.

See the README for more.