[flake8-bugbear] Do not raise error if keyword argument is present …

…and target-python version is less or equals than 3.9 (`B903`) (#15549)

crates/ruff_linter/resources/test/fixtures/flake8_bugbear/class_as_data_structure.py

@@ -95,4 +95,10 @@ def __init__(self, foo:int, bar:list):
         self.foo = foo
         self.bar = bar
 
+
+class KeywordOnly: # OK with python3.9 or less, not OK starting python3.10
+    def __init__(self, *, foo: int, bar: int):
+        self.foo = foo
+        self.bar = bar 
+
 # <-- end flake8-bugbear tests

crates/ruff_linter/src/rules/flake8_bugbear/mod.rs

@@ -16,6 +16,8 @@ mod tests {
     use crate::settings::LinterSettings;
     use crate::test::test_path;
 
+    use crate::settings::types::PythonVersion;
+
     #[test_case(Rule::AbstractBaseClassWithoutAbstractMethod, Path::new("B024.py"))]
     #[test_case(Rule::AssertFalse, Path::new("B011.py"))]
     #[test_case(Rule::AssertRaisesException, Path::new("B017.py"))]
@@ -78,6 +80,34 @@ mod tests {
         Ok(())
     }
 
+    #[test_case(
+        Rule::ClassAsDataStructure,
+        Path::new("class_as_data_structure.py"),
+        PythonVersion::Py39
+    )]
+    fn rules_with_target_version(
+        rule_code: Rule,
+        path: &Path,
+        target_version: PythonVersion,
+    ) -> Result<()> {
+        let snapshot = format!(
+            "{}_py{}{}_{}",
+            rule_code.noqa_code(),
+            target_version.major(),
+            target_version.minor(),
+            path.to_string_lossy(),
+        );
+        let diagnostics = test_path(
+            Path::new("flake8_bugbear").join(path).as_path(),
+            &LinterSettings {
+                target_version,
+                ..LinterSettings::for_rule(rule_code)
+            },
+        )?;
+        assert_messages!(snapshot, diagnostics);
+        Ok(())
+    }
+
     #[test]
     fn zip_without_explicit_strict() -> Result<()> {
         let snapshot = "B905.py";

crates/ruff_linter/src/rules/flake8_bugbear/rules/class_as_data_structure.rs

@@ -5,6 +5,7 @@ use ruff_python_semantic::analyze::visibility::{self, Visibility::Public};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
+use crate::settings::types::PythonVersion;
 
 /// ## What it does
 /// Checks for classes that only have a public `__init__` method,
@@ -77,6 +78,7 @@ pub(crate) fn class_as_data_structure(checker: &mut Checker, class_def: &ast::St
                         // skip `self`
                         .skip(1)
                         .all(|param| param.annotation().is_some() && !param.is_variadic())
+                    && (func_def.parameters.kwonlyargs.is_empty() || checker.settings.target_version >= PythonVersion::Py310)
                     // `__init__` should not have complicated logic in it
                     // only assignments
                     && func_def

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B903_class_as_data_structure.py.snap

@@ -66,6 +66,15 @@ class_as_data_structure.py:91:1: B903 Class could be dataclass or namedtuple
 95 | |         self.foo = foo
 96 | |         self.bar = bar
    | |______________________^ B903
-97 |
-98 |   # <-- end flake8-bugbear tests
    |
+
+class_as_data_structure.py:99:1: B903 Class could be dataclass or namedtuple
+    |
+ 99 | / class KeywordOnly: # OK with python3.9 or less, not OK starting python3.10
+100 | |     def __init__(self, *, foo: int, bar: int):
+101 | |         self.foo = foo
+102 | |         self.bar = bar 
+    | |______________________^ B903
+103 |
+104 |   # <-- end flake8-bugbear tests
+    |

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B903_py39_class_as_data_structure.py.snap

@@ -0,0 +1,69 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+class_as_data_structure.py:6:1: B903 Class could be dataclass or namedtuple
+  |
+6 | / class Point:  # B903
+7 | |     def __init__(self, x: float, y: float) -> None:
+8 | |         self.x = x
+9 | |         self.y = y
+  | |__________________^ B903
+  |
+
+class_as_data_structure.py:40:1: B903 Class could be dataclass or namedtuple
+   |
+38 |           ...
+39 |
+40 | / class C:   # B903
+41 | |     c: int
+42 | |     def __init__(self,d:list):
+43 | |         self.d = d
+   | |__________________^ B903
+44 |
+45 |   class D:   # B903
+   |
+
+class_as_data_structure.py:45:1: B903 Class could be dataclass or namedtuple
+   |
+43 |           self.d = d
+44 |
+45 | / class D:   # B903
+46 | |     """This class has a docstring."""
+47 | |     # this next method is an init
+48 | |     def __init__(self,e:dict):
+49 | |         self.e = e
+   | |__________________^ B903
+50 |
+51 |   # <--- begin flake8-bugbear tests below
+   |
+
+class_as_data_structure.py:63:1: B903 Class could be dataclass or namedtuple
+   |
+63 | / class NoWarningsClassAttributes:
+64 | |     spam = "ham"
+65 | |
+66 | |     def __init__(self, foo:int, bar:list):
+67 | |         self.foo = foo
+68 | |         self.bar = bar
+   | |______________________^ B903
+   |
+
+class_as_data_structure.py:85:1: B903 Class could be dataclass or namedtuple
+   |
+85 | / class Warnings:
+86 | |     def __init__(self, foo:int, bar:list):
+87 | |         self.foo = foo
+88 | |         self.bar = bar
+   | |______________________^ B903
+   |
+
+class_as_data_structure.py:91:1: B903 Class could be dataclass or namedtuple
+   |
+91 | / class WarningsWithDocstring:
+92 | |     """A docstring should not be an impediment to a warning"""
+93 | |
+94 | |     def __init__(self, foo:int, bar:list):
+95 | |         self.foo = foo
+96 | |         self.bar = bar
+   | |______________________^ B903
+   |