Don't support legacy Python

[pytorch]

Don't support legacy Python

[apaszke]

This looks like a reason to me:

[black-puppydog]

Sorry do be the necromancer here.

The numbers for the charts above are a bit hard to replicate, since download statistics from pypi have been disabled, then re-enabled in the meantime, and it's not entirely clear to me how good they were then and how good they are now.

So I just looked at the conda-cloud download numbers for 0.4.0 and 0.4.1, and it might be time to re-evaluate this.

Pytorch Version	Python 2.7	Python 3.X
0.4.0	20,900	165,057
0.4.1	14,578	127,007

There may be other sources of data that I didn't see or don't have access to, and there may be other reasons to further support legacy python, but I thought I'd put this out here.

[soumith]

One can get consistent PyPI download numbers over the last 1.5 years from this bigtable: https://bigquery.cloud.google.com/dataset/the-psf:pypi

Running a query to get the download numbers for the last ~3 months (since 2018-06-15):

SELECT
  file.project,
  file.version,
  file.type,
  file.filename,
  COUNT(*) as total_downloads,
FROM
  TABLE_DATE_RANGE(
    [the-psf:pypi.downloads],
    TIMESTAMP("20180615"),
    CURRENT_TIMESTAMP()
  )
WHERE
  file.project in ('torch')
GROUP BY
  file.project, file.version, file.filename, file.type 
ORDER BY total_downloads DESC
LIMIT 100

This gives:

file_project	file_version	file_type	file_filename	total_downloads
torch	0.4.1	bdist_wheel	torch-0.4.1-cp36-cp36m-manylinux1_x86_64.whl	107464
torch	0.4.1	bdist_wheel	torch-0.4.1-cp35-cp35m-manylinux1_x86_64.whl	76897
torch	0.4.1	bdist_wheel	torch-0.4.1-cp27-cp27mu-manylinux1_x86_64.whl	64493
torch	0.4.0	bdist_wheel	torch-0.4.0-cp36-cp36m-manylinux1_x86_64.whl	53572
torch	0.1.2.post1	sdist	torch-0.1.2.post1.tar.gz	33083
torch	0.3.1	bdist_wheel	torch-0.3.1-cp36-cp36m-manylinux1_x86_64.whl	25778
torch	0.4.0	bdist_wheel	torch-0.4.0-cp27-cp27mu-manylinux1_x86_64.whl	23750
torch	0.4.0	bdist_wheel	torch-0.4.0-cp35-cp35m-manylinux1_x86_64.whl	17091
torch	0.4.1	bdist_wheel	torch-0.4.1-cp36-cp36m-macosx_10_7_x86_64.whl	15014
torch	0.4.1.post2	bdist_wheel	torch-0.4.1.post2-cp37-cp37m-manylinux1_x86_64.whl	8977
torch	0.3.1	bdist_wheel	torch-0.3.1-cp27-cp27mu-manylinux1_x86_64.whl	8479
torch	0.4.1	bdist_wheel	torch-0.4.1-cp37-cp37m-macosx_10_7_x86_64.whl	6943
torch	0.4.1	bdist_wheel	torch-0.4.1-cp27-none-macosx_10_6_x86_64.whl	6496
torch	0.3.1	bdist_wheel	torch-0.3.1-cp35-cp35m-manylinux1_x86_64.whl	5504
torch	0.4.0	bdist_wheel	torch-0.4.0-cp36-cp36m-macosx_10_7_x86_64.whl	4059
torch	0.4.1	bdist_wheel	torch-0.4.1-cp37-cp37m-manylinux1_x86_64.whl	2852
torch	0.4.1	bdist_wheel	torch-0.4.1-cp35-cp35m-macosx_10_6_x86_64.whl	2495
torch	0.4.0	bdist_wheel	torch-0.4.0-cp27-none-macosx_10_6_x86_64.whl	1976
torch	0.4.1	bdist_wheel	torch-0.4.1-cp27-cp27m-manylinux1_x86_64.whl	1841
torch	0.3.1	bdist_wheel	torch-0.3.1-cp36-cp36m-macosx_10_7_x86_64.whl	1618
torch	0.4.0	bdist_wheel	torch-0.4.0-cp27-cp27m-manylinux1_x86_64.whl	1210
torch	0.4.0	bdist_wheel	torch-0.4.0-cp35-cp35m-macosx_10_6_x86_64.whl	1160
torch	0.1.2	sdist	torch-0.1.2.tar.gz	908
torch	0.3.1	bdist_wheel	torch-0.3.1-cp27-none-macosx_10_6_x86_64.whl	697
torch	0.3.1	bdist_wheel	torch-0.3.1-cp27-cp27m-manylinux1_x86_64.whl	494
torch	0.3.1	bdist_wheel	torch-0.3.1-cp35-cp35m-macosx_10_6_x86_64.whl	402
torch	0.3.0.post4	bdist_wheel	torch-0.3.0.post4-cp36-cp36m-macosx_10_7_x86_64.whl	299
torch	0.3.0.post4	bdist_wheel	torch-0.3.0.post4-cp27-none-macosx_10_6_x86_64.whl	254
torch	0.3.0.post4	bdist_wheel	torch-0.3.0.post4-cp35-cp35m-macosx_10_6_x86_64.whl	210

On PyPI, 2.7 is very much alive and kicking, still.
The reason Anaconda numbers are skewed is because anaconda brings it's Python, and a lot of users just start with miniconda3 instead of miniconda2

[black-puppydog]

Indeed, pypi gives a different picture.
After figuring out how to use bigquery (had to select "legacy" sql...) I played around with it a bit.
I aggregated the python/torch version numbers to only make the distinction between major python versions (2/3) and minor pytorch versions (i.e. ignoring postfixes such as "post1").

SELECT
  REGEXP_EXTRACT(file.version, r'^([0-9](?:\.[0-9]+)*)') as version,
  REGEXP_EXTRACT(details.python, r'^([2-3])\.[0-9].') as python_major,
  COUNT(*) as total_downloads,
FROM
  TABLE_DATE_RANGE(
    [the-psf:pypi.downloads],
    TIMESTAMP("20180615"),
    TIMESTAMP("20181015")
  )
WHERE
  file.project in ('torch')
--   AND (file.version = '0.4.0' OR file.version = '0.4.1')
GROUP BY 
  version, python_major
ORDER BY version, python_major ASC

Ignoring the requests that have no python version set (assuming they're distributed like the other downloads) that puts python 2 at about 24% for the 0.4.0 and 0.4.1 releases. So yeah, arguably still relevant. But is seems to be changing, finally. 🎉

[soumith]

@black-puppydog nice SQL skills, i might use that in the future.