[flake8-pyi] Implement PYI053

crates/ruff/resources/test/fixtures/flake8_pyi/PYI053.py

@@ -0,0 +1,38 @@
+def f1(x: str = "50 character stringggggggggggggggggggggggggggggggg") -> None:
+    ...
+
+
+def f2(x: str = "51 character stringgggggggggggggggggggggggggggggggg") -> None:
+    ...
+
+
+def f3(x: str = "50 character stringggggggggggggggggggggggggggggg\U0001f600") -> None:
+    ...
+
+
+def f4(x: str = "51 character stringgggggggggggggggggggggggggggggg\U0001f600") -> None:
+    ...
+
+
+def f5(x: bytes = b"50 character byte stringgggggggggggggggggggggggggg") -> None:
+    ...
+
+
+def f6(x: bytes = b"51 character byte stringgggggggggggggggggggggggggg") -> None:
+    ...
+
+
+def f7(x: bytes = b"50 character byte stringggggggggggggggggggggggggg\xff") -> None:
+    ...
+
+
+def f8(x: bytes = b"50 character byte stringgggggggggggggggggggggggggg\xff") -> None:
+    ...
+
+
+foo: str = "50 character stringggggggggggggggggggggggggggggggg"
+bar: str = "51 character stringgggggggggggggggggggggggggggggggg"
+
+baz: bytes = b"50 character byte stringgggggggggggggggggggggggggg"
+
+qux: bytes = b"51 character byte stringggggggggggggggggggggggggggg\xff"

crates/ruff/resources/test/fixtures/flake8_pyi/PYI053.pyi

@@ -0,0 +1,30 @@
+def f1(x: str = "50 character stringggggggggggggggggggggggggggggggg") -> None: ...  # OK
+def f2(
+    x: str = "51 character stringgggggggggggggggggggggggggggggggg",  # Error: PYI053
+) -> None: ...
+def f3(
+    x: str = "50 character stringggggggggggggggggggggggggggggg\U0001f600",  # OK
+) -> None: ...
+def f4(
+    x: str = "51 character stringgggggggggggggggggggggggggggggg\U0001f600",  # Error: PYI053
+) -> None: ...
+def f5(
+    x: bytes = b"50 character byte stringgggggggggggggggggggggggggg",  # OK
+) -> None: ...
+def f6(
+    x: bytes = b"51 character byte stringgggggggggggggggggggggggggg",  # Error: PYI053
+) -> None: ...
+def f7(
+    x: bytes = b"50 character byte stringggggggggggggggggggggggggg\xff",  # OK
+) -> None: ...
+def f8(
+    x: bytes = b"50 character byte stringgggggggggggggggggggggggggg\xff",  # Error: PYI053
+) -> None: ...
+
+foo: str = "50 character stringggggggggggggggggggggggggggggggg"  # OK
+
+bar: str = "51 character stringgggggggggggggggggggggggggggggggg"  # Error: PYI053
+
+baz: bytes = b"50 character byte stringgggggggggggggggggggggggggg"  # OK
+
+qux: bytes = b"51 character byte stringggggggggggggggggggggggggggg\xff"  # Error: PYI053

crates/ruff/src/checkers/ast/mod.rs

@@ -3393,6 +3393,14 @@ where
                     }
                 }
             }
+            Expr::Constant(ast::ExprConstant {
+                value: Constant::Bytes(_),
+                ..
+            }) => {
+                if self.is_stub && self.enabled(Rule::LongStringOrBytesInStub) {
+                    flake8_pyi::rules::long_string_or_bytes_in_stub(self, expr);
+                }
+            }
             Expr::Constant(ast::ExprConstant {
                 value: Constant::Str(value),
                 kind,
@@ -3427,6 +3435,9 @@ where
                 if self.enabled(Rule::UnicodeKindPrefix) {
                     pyupgrade::rules::unicode_kind_prefix(self, expr, kind.as_deref());
                 }
+                if self.is_stub && self.enabled(Rule::LongStringOrBytesInStub) {
+                    flake8_pyi::rules::long_string_or_bytes_in_stub(self, expr);
+                }
             }
             Expr::Lambda(
                 lambda @ ast::ExprLambda {

crates/ruff/src/codes.rs

@@ -599,6 +599,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8Pyi, "045") => (RuleGroup::Unspecified, Rule::IterMethodReturnIterable),
         (Flake8Pyi, "048") => (RuleGroup::Unspecified, Rule::StubBodyMultipleStatements),
         (Flake8Pyi, "052") => (RuleGroup::Unspecified, Rule::UnannotatedAssignmentInStub),
+        (Flake8Pyi, "053") => (RuleGroup::Unspecified, Rule::LongStringOrBytesInStub),
 
         // flake8-pytest-style
         (Flake8PytestStyle, "001") => (RuleGroup::Unspecified, Rule::PytestFixtureIncorrectParenthesesStyle),

crates/ruff/src/registry.rs

@@ -519,6 +519,7 @@ ruff_macros::register_rules!(
     rules::flake8_pyi::rules::DuplicateUnionMember,
     rules::flake8_pyi::rules::EllipsisInNonEmptyClassBody,
     rules::flake8_pyi::rules::CollectionsNamedTuple,
+    rules::flake8_pyi::rules::LongStringOrBytesInStub,
     rules::flake8_pyi::rules::NonEmptyStubBody,
     rules::flake8_pyi::rules::PassInClassBody,
     rules::flake8_pyi::rules::PassStatementStubBody,

crates/ruff/src/rules/flake8_pyi/mod.rs

@@ -50,6 +50,8 @@ mod tests {
     #[test_case(Rule::TypedArgumentDefaultInStub, Path::new("PYI011.pyi"))]
     #[test_case(Rule::UnannotatedAssignmentInStub, Path::new("PYI052.py"))]
     #[test_case(Rule::UnannotatedAssignmentInStub, Path::new("PYI052.pyi"))]
+    #[test_case(Rule::LongStringOrBytesInStub, Path::new("PYI053.py"))]
+    #[test_case(Rule::LongStringOrBytesInStub, Path::new("PYI053.pyi"))]
     #[test_case(Rule::UnprefixedTypeParam, Path::new("PYI001.py"))]
     #[test_case(Rule::UnprefixedTypeParam, Path::new("PYI001.pyi"))]
     #[test_case(Rule::UnrecognizedPlatformCheck, Path::new("PYI007.py"))]

crates/ruff/src/rules/flake8_pyi/rules/long_string_or_bytes_in_stub.rs

@@ -0,0 +1,43 @@
+use ruff_diagnostics::{Diagnostic, Violation};
+use rustpython_parser::ast::{self, Constant, Expr, Ranged};
+
+use ruff_macros::{derive_message_formats, violation};
+
+use crate::checkers::ast::Checker;
+
+#[violation]
+pub struct LongStringOrBytesInStub;
+
+/// ## What it does
+/// Checks for `str` or `bytes` literals longer than 50 characters in stubs.
+///
+/// ## Why is this bad?
+/// Extremely long strings used as argument defaults or otherwise are unlikely to be useful for
+/// users. Consider replacing them with ellipses.
+impl Violation for LongStringOrBytesInStub {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!("`str` and `bytes` literals longer than 50 characters should not be used in stubs.")
+    }
+}
+
+/// PYI053
+pub(crate) fn long_string_or_bytes_in_stub(checker: &mut Checker, expr: &Expr) {
+    let length = match expr {
+        Expr::Constant(ast::ExprConstant {
+            value: Constant::Str(s),
+            ..
+        }) => s.chars().count(),
+        Expr::Constant(ast::ExprConstant {
+            value: Constant::Bytes(bytes),
+            ..
+        }) => bytes.len(),
+        _ => return,
+    };
+
+    if length > 50 {
+        checker
+            .diagnostics
+            .push(Diagnostic::new(LongStringOrBytesInStub, expr.range()));
+    }
+}

crates/ruff/src/rules/flake8_pyi/rules/mod.rs

@@ -11,6 +11,9 @@ pub(crate) use ellipsis_in_non_empty_class_body::{
 pub(crate) use iter_method_return_iterable::{
     iter_method_return_iterable, IterMethodReturnIterable,
 };
+pub(crate) use long_string_or_bytes_in_stub::{
+    long_string_or_bytes_in_stub, LongStringOrBytesInStub,
+};
 pub(crate) use non_empty_stub_body::{non_empty_stub_body, NonEmptyStubBody};
 pub(crate) use pass_in_class_body::{pass_in_class_body, PassInClassBody};
 pub(crate) use pass_statement_stub_body::{pass_statement_stub_body, PassStatementStubBody};
@@ -39,6 +42,7 @@ mod docstring_in_stubs;
 mod duplicate_union_member;
 mod ellipsis_in_non_empty_class_body;
 mod iter_method_return_iterable;
+mod long_string_or_bytes_in_stub;
 mod non_empty_stub_body;
 mod pass_in_class_body;
 mod pass_statement_stub_body;

crates/ruff/src/rules/flake8_pyi/snapshots/ruff__rules__flake8_pyi__tests__PYI053_PYI053.py.snap

@@ -0,0 +1,4 @@
+---
+source: crates/ruff/src/rules/flake8_pyi/mod.rs
+---
+

crates/ruff/src/rules/flake8_pyi/snapshots/ruff__rules__flake8_pyi__tests__PYI053_PYI053.pyi.snap

@@ -0,0 +1,41 @@
+---
+source: crates/ruff/src/rules/flake8_pyi/mod.rs
+---
+PYI053.pyi:3:14: PYI053 `str` and `bytes` literals longer than 50 characters should not be used in stubs.
+  |
+3 | def f1(x: str = "50 character stringggggggggggggggggggggggggggggggg") -> None: ...  # OK
+4 | def f2(
+5 |     x: str = "51 character stringgggggggggggggggggggggggggggggggg",  # Error: PYI053
+  |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PYI053
+6 | ) -> None: ...
+7 | def f3(
+  |
+
+PYI053.pyi:21:16: PYI053 `str` and `bytes` literals longer than 50 characters should not be used in stubs.
+   |
+21 | ) -> None: ...
+22 | def f8(
+23 |     x: bytes = b"50 character byte stringgggggggggggggggggggggggggg\xff",  # Error: PYI053
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PYI053
+24 | ) -> None: ...
+   |
+
+PYI053.pyi:26:12: PYI053 `str` and `bytes` literals longer than 50 characters should not be used in stubs.
+   |
+26 | foo: str = "50 character stringggggggggggggggggggggggggggggggg"  # OK
+27 | 
+28 | bar: str = "51 character stringgggggggggggggggggggggggggggggggg"  # Error: PYI053
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PYI053
+29 | 
+30 | baz: bytes = b"50 character byte stringgggggggggggggggggggggggggg"  # OK
+   |
+
+PYI053.pyi:30:14: PYI053 `str` and `bytes` literals longer than 50 characters should not be used in stubs.
+   |
+30 | baz: bytes = b"50 character byte stringgggggggggggggggggggggggggg"  # OK
+31 | 
+32 | qux: bytes = b"51 character byte stringggggggggggggggggggggggggggg\xff"  # Error: PYI053
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ PYI053
+   |
+
+