Dropping __future__ from cmssw

[smuzaffar]

We have many python files (over 900) with statements like [a] which we had added for python2/3 compatibility. As CMSSW only supports python3, so I suggest to remove all these lines.

We will open PRs (one per category) to remove these statements.

[a]

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

[smuzaffar]

FYI @cms-sw/all-l2

[cmsbuild]

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[cmsbuild]

A new Issue was created by @smuzaffar.

@Dr15Jones, @antoniovilela, @makortel, @mandrenguyen, @rappoccio, @sextonkennedy, @smuzaffar can you please review it and eventually sign/assign? Thanks.

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[makortel]

assign core

[cmsbuild]

New categories assigned: core

@Dr15Jones,@makortel,@smuzaffar you have been requested to review this Pull request/Issue and eventually sign? Thanks

[kpedro88]

@smuzaffar according to https://docs.python.org/3/library/__future__.html#module-contents, I do not think from __future__ import annotations should be dropped in this cleanup. This is a python3-specific feature. (generator_stop is also on the list of newer python3-only __future__ features, but that one does not currently appear to be used anywhere in CMSSW.)

[smuzaffar]

thanks @kpedro88 , you are right annotations will be default in python 4 so yes from __future__ import annotations should not be removed. Luckily we only have one place where it is used. I have updated the PR to reintroduce it.