Tighten str subclass conversion regression

Copilot · youknowone · Copilot · commit 008e4c6fdb45 · 2026-03-17T14:35:43.000Z
Co-authored-by: youknowone &lt;69878+youknowone@users.noreply.github.com&gt;
diff --git a/Lib/test/test_str.py b/Lib/test/test_str.py
@@ -2441,6 +2441,10 @@ def __str__(self):
         self.assertTypedEqual(StrSubclass(StrWithStr(OtherStrSubclass('abc'))),
                               StrSubclass('abc'))
 
+        str_value = StrSubclass('abc')
+        self.assertIs(str(WithStr(str_value)), str_value)
+        self.assertIs(str(StrWithStr(str_value)), str_value)
+
         self.assertTypedEqual(str(WithRepr('<abc>')), '<abc>')
         self.assertTypedEqual(str(WithRepr(StrSubclass('<abc>'))), StrSubclass('<abc>'))
         self.assertTypedEqual(StrSubclass(WithRepr('<abc>')), StrSubclass('<abc>'))
@@ -2449,6 +2453,9 @@ def __str__(self):
         self.assertTypedEqual(StrSubclass(WithRepr(OtherStrSubclass('<abc>'))),
                               StrSubclass('<abc>'))
 
+        repr_value = StrSubclass('<abc>')
+        self.assertIs(str(WithRepr(repr_value)), repr_value)
+
     def test_unicode_repr(self):
         class s1:
             def __repr__(self):
