[harikb]

The trouble is I publish a (new) code that advertises itself as working on 3.x and then it turns out it is being used by a person who only had the version prior to this change.

That said, Go made a similar change (from insertion-order to explicitly-randomized) and world didn’t end. So there’s that.

[ryebit]

If your code relies on a minimum python version, you can add `python_requires=">=3.5"` to your setup.py [https://packaging.python.org/guides/distributing-packages-us...] to ensure it's not installed on older releases.

That field itself is kinda new; but if needing to block users with older versions, that shouldn't be an issue.

[hprotagonist]

personally, i just drop a f-string in setup.py and that'll filter out any python for which this issue pertains.

[baq]

This might not work if you’re distributing a wheel.

[AdamN]

Python 3.4 is EOL anyway so there's no need to do this. Anybody running 3.4 is already unsupported.

[hprotagonist]

and 3.5 dies in september. hurray!

[strken]

I thought Go made the change from undefined behaviour with an underlying implementation that was insertion order in a map with 8 or fewer entries, to similarly undefined behaviour with an implementation that randomised lookups in those cases. Any code that has ever relied on any kind of ordering in Go maps will almost certainly be wrong, even random ordering, because the distribution of the "random" ordering is biased.

See https://medium.com/i0exception/map-iteration-in-go-275abb76f...

[throwaway894345]

FWIW, when Go made that change, it was a much less-widely-used language (smaller blast radius).