[issue39110] It seems that list() changes the value of the parameter

[ctarn]

ctarn <i at ctarn.io> added the comment:

In the code, each item of ls = [[0], [1], [2],...] has an owner pointing to d, which is a Tree inheriting from collections.UserList.
When `d[0] = a`, and `a.owner = d`, and `_ = list(d[0:1])` is called, a.owner will be changed to d[0:1].

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue39110>
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