Previously Linter::parse_code("E401") returned
(Linter::Pycodestyle, "401") ... after this commit it returns
(Linter::Pycodestyle, "E401") instead, which is important
for the future implementation of the many-to-many mapping.
(The second value of the tuple isn't used currently.)
Fixes a regression introduced in 4e4643aa5d.
We want the longest prefixes to be checked first so we of course
have to reverse the sorting when sorting by prefix length.
Fixes#2210.
We already enforced pedantic clippy lints via the
following command in .github/workflows/ci.yaml:
cargo clippy --workspace --all-targets --all-features -- -D warnings -W clippy::pedantic
Additionally adding #![warn(clippy::pedantic)] to all main.rs and lib.rs
has the benefit that violations of pedantic clippy lints are also
reported when just running `cargo clippy` without any arguments and
are thereby also picked up by LSP[1] servers such as rust-analyzer[2].
However for rust-analyzer to run clippy you'll have to configure:
"rust-analyzer.check.command": "clippy",
in your editor.[3]
[1]: https://microsoft.github.io/language-server-protocol/
[2]: https://rust-analyzer.github.io/
[3]: https://rust-analyzer.github.io/manual.html#configuration
This commit removes rule redirects such as ("U" -> "UP") from the
RuleCodePrefix enum because they complicated the generation of that enum
(which we want to change to be prefix-agnostic in the future).
To preserve backwards compatibility redirects are now resolved
before the strum-generated RuleCodePrefix::from_str is invoked.
This change also brings two other advantages:
* Redirects are now only defined once
(previously they had to be defined twice:
once in ruff_macros/src/rule_code_prefix.rs
and a second time in src/registry.rs).
* The deprecated redirects will no longer be suggested in IDE
autocompletion within pyproject.toml since they are now no
longer part of the ruff.schema.json.
Yet another refactor to let us implement the many-to-many mapping
between codes and rules in a prefix-agnostic way.
We want to break up the RuleCodePrefix[1] enum into smaller enums.
To facilitate that this commit introduces a new wrapping type around
RuleCodePrefix so that we can start breaking it apart.
[1]: Actually `RuleCodePrefix` is the previous name of the autogenerated
enum ... I renamed it in b19258a243 to
RuleSelector since `ALL` isn't a prefix. This commit now renames it back
but only because the new `RuleSelector` wrapper type, introduced in this
commit, will let us move the `ALL` variant from `RuleCodePrefix` to
`RuleSelector` in the next commit.
To enable ruff_dev to automatically generate the rule Markdown tables in
the README the ruff library contained the following function:
Linter::codes() -> Vec<RuleSelector>
which was slightly changed to `fn prefixes(&self) -> Prefixes` in
9dc66b5a65 to enable ruff_dev to split
up the Markdown tables for linters that have multiple prefixes
(pycodestyle has E & W, Pylint has PLC, PLE, PLR & PLW).
The definition of this method was however largely redundant with the
#[prefix] macro attributes in the Linter enum, which are used to
derive the Linter::parse_code function, used by the --explain command.
This commit removes the redundant Linter::prefixes by introducing a
same-named method with a different signature to the RuleNamespace trait:
fn prefixes(&self) -> &'static [&'static str];
As well as implementing IntoIterator<Rule> for &Linter. We extend the
extisting RuleNamespace proc macro to automatically derive both
implementations from the Linter enum definition.
To support the previously mentioned Markdown table splitting we
introduce a very simple hand-written method to the Linter impl:
fn categories(&self) -> Option<&'static [LinterCategory]>;
ParseCode was a fitting name since the trait only contained a single
parse_code method ... since we now however want to introduce an
additional `prefixes` method RuleNamespace is more fitting.
Using Ident as the key type is inconvenient since creating an Ident
requires the specification of a Span, which isn't actually used by
the Hash implementation of Ident.
543865c96b introduced
RuleCode::origin() -> RuleOrigin generation via a macro, while that
signature now has been renamed to Rule::origin() -> Linter we actually
want to get rid of it since rules and linters shouldn't be this tightly
coupled (since one rule can exist in multiple linters).
Another disadvantage of the previous approach was that the prefixes
had to be defined in ruff_macros/src/prefixes.rs, which was easy to
miss when defining new linters in src/*, case in point
INP001 => violations::ImplicitNamespacePackage has in the meantime been
added without ruff_macros/src/prefixes.rs being updated accordingly
which resulted in `ruff --explain INP001` mistakenly reporting that the
rule belongs to isort (since INP001 starts with the isort prefix "I").
The derive proc macro introduced in this commit requires every variant
to have at least one #[prefix = "..."], eliminating such mistakes.
More accurate since the enum also encompasses:
* ALL (which isn't a prefix at all)
* fully-qualified rule codes (which aren't prefixes unless you say
they're a prefix to the empty string but that's not intuitive)
"origin" was accurate since ruff rules are currently always modeled
after one origin (except the Ruff-specific rules).
Since we however want to introduce a many-to-many mapping between codes
and rules, the term "origin" no longer makes much sense. Rules usually
don't have multiple origins but one linter implements a rule first and
then others implement it later (often inspired from another linter).
But we don't actually care much about where a rule originates from when
mapping multiple rule codes to one rule implementation, so renaming
RuleOrigin to Linter is less confusing with the many-to-many system.
As we surface rule names more to users we want
them to be easier to type than PascalCase.
Prior art:
Pylint and ESLint also use kebab-case for their rule names.
Clippy uses snake_case but only for syntactical reasons
(so that the argument to e.g. #![allow(clippy::some_lint)]
can be parsed as a path[1]).
[1]: https://doc.rust-lang.org/reference/paths.html
The idea is nice and simple we replace:
fn placeholder() -> Self;
with
fn message_formats() -> &'static [&'static str];
So e.g. if a Violation implementation defines:
fn message(&self) -> String {
format!("Local variable `{name}` is assigned to but never used")
}
it would also have to define:
fn message_formats() -> &'static [&'static str] {
&["Local variable `{name}` is assigned to but never used"]
}
Since we however obviously do not want to duplicate all of our format
strings we simply introduce a new procedural macro attribute
#[derive_message_formats] that can be added to the message method
declaration in order to automatically derive the message_formats
implementation.
This commit implements the macro. The following and final commit
updates violations.rs to use the macro. (The changes have been separated
because the next commit is autogenerated via a Python script.)
ruff_dev::generate_rules_table previously documented which rules are
autofixable via DiagnosticKind::fixable ... since the DiagnosticKind was
obtained via Rule::kind (and Violation::placeholder) which we both want
to get rid of we have to obtain the autofixability via another way.
This commit implements such another way by adding an AUTOFIX
associated constant to the Violation trait. The constant is of the type
Option<AutoFixkind>, AutofixKind is a new struct containing an
Availability enum { Sometimes, Always}, letting us additionally document
that some autofixes are only available sometimes (which previously
wasn't documented). We intentionally introduce this information in a
struct so that we can easily introduce further autofix metadata in the
future such as autofix applicability[1].
[1]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_errors/enum.Applicability.html
This commit series removes the following associated
function from the Violation trait:
fn placeholder() -> Self;
ruff previously used this placeholder approach for the messages it
listed in the README and displayed when invoked with --explain <code>.
This approach is suboptimal for three reasons:
1. The placeholder implementations are completely boring code since they
just initialize the struct with some dummy values.
2. Displaying concrete error messages with arbitrary interpolated values
can be confusing for the user since they might not recognize that the
values are interpolated.
3. Some violations have varying format strings depending on the
violation which could not be documented with the previous approach
(while we could have changed the signature to return Vec<Self> this
would still very much suffer from the previous two points).
We therefore drop Violation::placeholder in favor of a new macro-based
approach, explained in commit 4/5.
Violation::placeholder is only invoked via Rule::kind, so we firstly
have to get rid of all Rule::kind invocations ... this commit starts
removing the trivial cases.
Since the UI still relies on the rule codes this improves the developer
experience by letting developers view the code of a Rule enum variant by
hovering over it.
This commit series refactors ruff to decouple "rules" from "rule codes",
in order to:
1. Make our code more readable by changing e.g.
RuleCode::UP004 to Rule::UselessObjectInheritance.
2. Let us cleanly map multiple codes to one rule, for example:
[UP004] in pyupgrade, [R0205] in pylint and [PIE792] in flake8-pie
all refer to the rule UselessObjectInheritance but ruff currently
only associates that rule with the UP004 code (since the
implementation was initially modeled after pyupgrade).
3. Let us cleanly map one code to multiple rules, for example:
[C0103] from pylint encompasses N801, N802 and N803 from pep8-naming.
The latter two steps are not yet implemented by this commit series
but this refactoring enables us to introduce such a mapping. Such a
mapping would also let us expand flake8_to_ruff to support e.g. pylint.
After the next commit which just does some renaming the following four
commits remove all trait derivations from the Rule (previously RuleCode)
enum that depend on the variant names to guarantee that they are not
used anywhere anymore so that we can rename all of these variants in the
eigth and final commit without breaking anything.
While the plan very much is to also surface these human-friendly names
more in the user interface this is not yet done in this commit series,
which does not change anything about the UI: it's purely a refactor.
[UP004]: pyupgrade doesn't actually assign codes to its messages.
[R0205]: https://pylint.pycqa.org/en/latest/user_guide/messages/refactor/useless-object-inheritance.html
[PIE792]: https://github.com/sbdchd/flake8-pie#pie792-no-inherit-object
[C0103]: https://pylint.pycqa.org/en/latest/user_guide/messages/convention/invalid-name.html
