[ruff] Fix false positives on starred arguments (RUF057)

crates/ruff_linter/resources/test/fixtures/ruff/RUF057.py

@@ -81,3 +81,7 @@
 round(
     17 # a comment
 )
+
+# See: https://github.com/astral-sh/ruff/issues/21209
+print(round(125, **{"ndigits": -2}))
+print(round(125, *[-2]))

crates/ruff_linter/src/rules/ruff/rules/unnecessary_round.rs

@@ -143,6 +143,15 @@ pub(super) fn rounded_and_ndigits<'a>(
         return None;
     }
 
+    // *args
+    if arguments.args.iter().any(Expr::is_starred_expr) {
+        return None;
+    }
+    // **kwargs
+    if arguments.keywords.iter().any(|kw| kw.arg.is_none()) {
+        return None;
+    }
+
     let rounded = arguments.find_argument_value("number", 0)?;
     let ndigits = arguments.find_argument_value("ndigits", 1);
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF057_RUF057.py.snap

@@ -253,6 +253,8 @@ RUF057 [*] Value being rounded is already an integer
 82 | |     17 # a comment
 83 | | )
    | |_^
+84 |
+85 |   # See: https://github.com/astral-sh/ruff/issues/21209
    |
 help: Remove unnecessary `round` call
 78 | round(# a comment
@@ -262,4 +264,7 @@ help: Remove unnecessary `round` call
    -     17 # a comment
    - )
 81 + 17
+82 | 
+83 | # See: https://github.com/astral-sh/ruff/issues/21209
+84 | print(round(125, **{"ndigits": -2}))
 note: This is an unsafe fix and may change runtime behavior