Avoid PEP 604 panic with empty tuple (#3526)

astral-sh · Mar 14, 2023 · 58353a4 · 58353a4
1 parent a36139a
commit 58353a4
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diff --git a/crates/ruff/resources/test/fixtures/pyupgrade/UP038.py b/crates/ruff/resources/test/fixtures/pyupgrade/UP038.py
@@ -5,3 +5,4 @@
 issubclass("yes", int)  # OK
 isinstance(1, int | float)  # OK
 issubclass("yes", int | str)  # OK
+isinstance(1, ())  # OK
diff --git a/crates/ruff/src/rules/pyupgrade/rules/use_pep604_isinstance.rs b/crates/ruff/src/rules/pyupgrade/rules/use_pep604_isinstance.rs
@@ -68,6 +68,7 @@ fn union(elts: &[Expr]) -> Expr {
     }
 }
 
+/// UP038
 pub fn use_pep604_isinstance(checker: &mut Checker, expr: &Expr, func: &Expr, args: &[Expr]) {
     if let ExprKind::Name { id, .. } = &func.node {
         let Some(kind) = CallKind::from_name(id) else {
@@ -78,6 +79,9 @@ pub fn use_pep604_isinstance(checker: &mut Checker, expr: &Expr, func: &Expr, ar
         };
         if let Some(types) = args.get(1) {
             if let ExprKind::Tuple { elts, .. } = &types.node {
+                if elts.is_empty() {
+                    return;
+                }
                 let mut diagnostic =
                     Diagnostic::new(IsinstanceWithTuple { kind }, Range::from(expr));
                 if checker.patch(diagnostic.kind.rule()) {