[llvm-dev] Migrate utils/ Python 2 scripts to Python 3

[Fāng-ruì Sòng via llvm-dev]

Thanks for the information. Then how about standalone scripts (many
one-file) like utils/update_check_tests.py that are unrelated to lit
or other important infrastructure? Can they be changed from
`#!/usr/bin/python2.7` to `#!/usr/bin/python3` shebang?

On Tue, Jan 30, 2018 at 11:20 AM, Chris Matthews
<chris.matthews at apple.com> wrote:
> Personally, every machine I work with only has Python 2.7.
>
> Justin is correct that there is a non-trivial amount of effort to convert
> the bots.
>
> Python 3 is wonderful. But, a Python 3 dependency seems like one burden that
> could be avoided.  We have already made that trade-off in the past, for
> example by only using standard python packages, so there is less/nothing to
> pip install when getting started.  Dependencies likes host compiler and
> cmake totally make sense given they are central to how LLVM is made.  I
> don’t think the same for the python code.
>
> I’m in favor of 2/3 compatibility until the death clock ends.
>
>
> On Jan 30, 2018, at 4:48 AM, 陳韋任 via llvm-dev <llvm-dev at lists.llvm.org>
> wrote:
>
> Does Python 3 have feature we want to use in LLVM codebase, and no
> workaround there? If so, please give some examples. I think that makes the
> discussion more concrete.
>
> 2018-01-30 4:46 GMT+08:00 Fāng-ruì Sòng via llvm-dev
> <llvm-dev at lists.llvm.org>:
>>
>> Hi LLVM-Devs,
>>
>> I noticed that many Python scripts under utils/ have a shebang of
>> `#!/usr/bin/python` (which is a symlink to python2.7 on many platforms)
>> and some of them use Python 2 syntax that is not compatible with Python 3
>> (e.g. print statements; str/bytes)
>>
>> I created a revision to migrate utils/update_{llc_,}_test_checks.py from
>> Python 2 to Python 3 https://reviews.llvm.org/D42450 , the arguments against
>> making it Python 3 is:
>>
>> * There are many Mac OS X users and Mac OS X 10.8 comes with Python 2.7
>> pre-installed [0] but not Python 3.
>> * Forcing scripts to use Python 3 (by doing so we can avoid some
>> compatibility trouble) may not be a good idea.
>>
>> Python 2.7 was published in 2010 and planned as the last of the 2.x
>> releases. It will not be maintained past 2020 and there is also a retirement
>> page https://pythonclock.org/ .
>>
>> The second argument would not need to be addressed if the first one did
>> not lay too much burden on developers. After all, we have to install `cmake,
>> ninja/GNU Make / libedit(for lldb)` to build LLVM. These packages are not
>> installed by default on many platforms.
>>
>> Thoughts on deprecating Python 2 for utils/ scripts (different from
>> libclang or lldb scripts) which are not user-facing?
>>
>> [0]:
>> https://docs.python.org/3/using/mac.html#getting-and-installing-macpython
>>
>>
>> Thanks,
>> Fangrui
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
>
>
>
> --
> Wei-Ren Chen (陳韋任)
> Homepage: https://people.cs.nctu.edu.tw/~chenwj
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>



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