Re: [Python-Dev] Python3.7 backwards incompatible

2018-06-23 Thread Ivan Levkivskyi
This particular breakage is explicitly listed in PEP 560, see an example with List and List[int] in https://www.python.org/dev/peps/pep-0560/#backwards-compatibility-and-impact-on-users-who-don-t-use-typing In general, isinstance() with typing types should be avoided when possible (Mark Shannon wh

Re: [Python-Dev] Python3.7 backwards incompatible

2018-06-23 Thread Guido van Rossum
First, the typing module is still provisional, so there is no strict backwards compatibility guarantee. With that out of the way, I can reproduce your problem, and I assume it's caused by the implementation of PEP 560, which is meant to speed up the typing module (among other goals). I'm wonderin

[Python-Dev] Python3.7 backwards incompatible

2018-06-23 Thread Rokker Ruslan
Python 3.7 in the status of RC, but I do not see information about the fact that python3.7 is backwards incompatible with python3.5. $ ~ python3.5Python 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609] on linuxType "help", "copyright", "credits" or "license" for more information.>>> from