New submission from Curtis M <3ed7qja...@liamekaens.com>:
Example code to replicate issue on python 3.10.2 is attached. How to replicate issue: 1. Define a namedtuple where all fields have default values. At least one field's default value will be an empty list: [] 2. Instantiate 2 instances of the namedtuple. 3. In the first instance, use namedtuple._replace() to add a replacement list into a field that defaults to []. 4. Now look at the contents of both namedtuples. *Both* of them are modified, even though the code only modified the first object. *** Output from attached example code: g.P5 1: myNamedTuple(P1='hello', P2='world', P3=None, P4='', P5=[], P6=[]) h.P5 1: myNamedTuple(P1='good', P2='morning', P3=None, P4='', P5=[], P6=[]) Expected: g.P5: [] Actual: g.P5: [] Expected: h.P5: [] Actual: h.P5: [] g.P5 2: myNamedTuple(P1='hello', P2='world', P3=None, P4='', P5=['a', 'b'], P6=[]) h.P5 2: myNamedTuple(P1='good', P2='morning', P3=None, P4='', P5=['a', 'b'], P6=[]) Expected: g.P5: ['a', 'b'] Actual: g.P5: ['a', 'b'] Expected: h.P5: [] Actual: h.P5: ['a', 'b'] g.P5 3: myNamedTuple(P1='hello', P2='world', P3=None, P4='', P5=['a', 'b', 'c', 'd'], P6=[]) h.P5 3: myNamedTuple(P1='good', P2='morning', P3=None, P4='', P5=['a', 'b', 'c', 'd'], P6=[]) Expected: g.P5: ['a', 'b', 'c', 'd'] Actual: g.P5: ['a', 'b', 'c', 'd'] Expected: h.P5: [] Actual: h.P5: ['a', 'b', 'c', 'd'] ---------- components: Library (Lib) files: namedtuple_example.py messages: 411079 nosy: user027.7 priority: normal severity: normal status: open title: namedtuple leaks data between instances when field's default value is empty list type: behavior versions: Python 3.10 Added file: https://bugs.python.org/file50568/namedtuple_example.py _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue46450> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
