
On 15 April 2016 at 18:54, Jim J. Jewett <jimjjewett@gmail.com> wrote:
[2A] Do you want to promise that replacing a value with a non-identical object *will* trigger a version_tag update *even* if the objects are equal?
I would vote no, but I realize backwards-compatibility may create such a promise implicitly.
It needs to trigger a version update. Equality doesn't guarantee any kind of equivalence in Python. It's not even guaranteed that a==b will come to the same value if evaluated twice in a row. An example:
from fractions import Fraction as F F(1) == 1 True d = globals() d['a'] = F(1) a.limit_denominator() Fraction(1, 1) d['a'] = 1 a.limit_denominator() Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'int' object has no attribute 'limit_denominator'
-- Oscar