Parenthesize NamedExpr if target breaks (#6714)

crates/ruff_python_formatter/resources/test/fixtures/ruff/expression/named_expr.py

@@ -47,6 +47,13 @@ if (
 ):
     pass
 
+if (
+    x # 2
+    := # 3
+    y
+):
+    pass
+
 y0 = (y1 := f(x))
 
 f(x:=y, z=True)

crates/ruff_python_formatter/src/expression/expr_named_expr.rs

@@ -75,7 +75,7 @@ impl NeedsParentheses for ExprNamedExpr {
         {
             OptionalParentheses::Always
         } else {
-            OptionalParentheses::Never
+            OptionalParentheses::Multiline
         }
     }
 }

crates/ruff_python_formatter/tests/snapshots/format@expression__named_expr.py.snap

@@ -53,6 +53,13 @@ if (
 ):
     pass
 
+if (
+    x # 2
+    := # 3
+    y
+):
+    pass
+
 y0 = (y1 := f(x))
 
 f(x:=y, z=True)
@@ -149,6 +156,13 @@ if (
 ):
     pass
 
+if (
+    x  # 2
+    :=  # 3
+    y
+):
+    pass
+
 y0 = (y1 := f(x))
 
 f(x := y, z=True)