[ruff] Fix B004 to skip invalid hasattr/getattr calls

crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B004.py

@@ -52,3 +52,21 @@ def __init__(self): self.__call__ = None
 
 assert hasattr(A(), "__call__")
 assert callable(A()) is False
+
+# https://github.com/astral-sh/ruff/issues/20440
+def test_invalid_hasattr_calls():
+    hasattr(0, "__call__", 0)  # 3 args - invalid
+    hasattr(0, "__call__", x=0)  # keyword arg - invalid
+    hasattr(0, "__call__", 0, x=0)  # 3 args + keyword - invalid
+    hasattr()  # no args - invalid
+    hasattr(0)  # 1 arg - invalid
+    hasattr(*(), "__call__", "extra")  # unpacking - invalid
+    hasattr(*())  # unpacking - invalid
+
+def test_invalid_getattr_calls():
+    getattr(0, "__call__", None, "extra")  # 4 args - invalid
+    getattr(0, "__call__", default=None)  # keyword arg - invalid
+    getattr()  # no args - invalid
+    getattr(0)  # 1 arg - invalid
+    getattr(*(), "__call__", None, "extra")  # unpacking - invalid
+    getattr(*())  # unpacking - invalid

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -717,7 +717,9 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 flake8_bugbear::rules::re_sub_positional_args(checker, call);
             }
             if checker.is_rule_enabled(Rule::UnreliableCallableCheck) {
-                flake8_bugbear::rules::unreliable_callable_check(checker, expr, func, args);
+                flake8_bugbear::rules::unreliable_callable_check(
+                    checker, expr, func, args, keywords,
+                );
             }
             if checker.is_rule_enabled(Rule::StripWithMultiCharacters) {
                 flake8_bugbear::rules::strip_with_multi_characters(checker, expr, func, args);

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

@@ -90,7 +90,11 @@ pub(crate) fn unreliable_callable_check(
     expr: &Expr,
     func: &Expr,
     args: &[Expr],
+    keywords: &[ast::Keyword],
 ) {
+    if !keywords.is_empty() {
+        return;
+    }
     let [obj, attr, ..] = args else {
         return;
     };
@@ -103,7 +107,21 @@ pub(crate) fn unreliable_callable_check(
     let Some(builtins_function) = checker.semantic().resolve_builtin_symbol(func) else {
         return;
     };
-    if !matches!(builtins_function, "hasattr" | "getattr") {
+
+    // Validate function arguments based on function name
+    let valid_args = match builtins_function {
+        "hasattr" => {
+            // hasattr should have exactly 2 positional arguments and no keywords
+            args.len() == 2
+        }
+        "getattr" => {
+            // getattr should have 2 or 3 positional arguments and no keywords
+            args.len() == 2 || args.len() == 3
+        }
+        _ => return,
+    };
+
+    if !valid_args {
         return;
     }
 

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B004_B004.py.snap

@@ -156,4 +156,6 @@ help: Replace with `callable()`
    - assert hasattr(A(), "__call__")
 53 + assert callable(A())
 54 | assert callable(A()) is False
+55 | 
+56 | # https://github.com/astral-sh/ruff/issues/20440
 note: This is an unsafe fix and may change runtime behavior