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Preserve str subclass results from __repr__ in plain str() #7454

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Preserve str subclass results from __repr__ in plain str() #7454

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8a56d78
Initial plan
Copilot Mar 17, 2026
ed2fd1e
Preserve str subclass returned by __repr__
Copilot Mar 17, 2026
2ff66e7
Format str constructor fast path
Copilot Mar 17, 2026
5140534
Tighten str subclass conversion regression
Copilot Mar 17, 2026
9a11d44
Align test_str with CPython and move local coverage
Copilot Mar 19, 2026
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Tighten str subclass conversion regression 
Co-authored-by: youknowone <69878+youknowone@users.noreply.github.com>
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@youknowone
Copilot and youknowone committed Mar 28, 2026
commit 514053415cbe168fb776db83efac2d61e690a1f7
7 changes: 7 additions & 0 deletions Lib/test/test_str.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2440,6 +2440,10 @@ 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>'))
Expand All @@ -2448,6 +2452,9 @@ 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):
Expand Down