NOMRG Comments on prototype weights and model builders

[NicolasHug]

Here are a bunch of comments on the new weights prototype. I'm opening this as a PR (not to be merged) instead of an issue as I think it will better help localize each discussion.

Overall I don't have any major comment or concern, except maybe for the somewhat BC breaking changes of some model building functions. I think we can work around BC for some of them, but not all.

[facebook-github-bot]

💊 CI failures summary and remediations

As of commit 500f826 (more details on the Dr. CI page):

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• 1/1 failures introduced in this PR

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🕵️ 1 new failure recognized by patterns

The following CI failures do not appear to be due to upstream breakages:

python_type_check (1/1)

Step: "sudo apt-get update -y
sudo apt install -y libturbojpeg-dev
pip install --user --progress-bar off mypy
pip install --user --progress-bar off types-requests
pip install --user --progress-bar off --pre torch -f https://download.pytorch.org/whl/nightly/cpu/torch_nightly.html
pip install --user --progress-bar off git+https://github.com/pytorch/data.git
pip install --user --progress-bar off --no-build-isolation --editable .
mypy --config-file mypy.ini
" (full log | diagnosis details | 🔁 rerun)

Found 2 errors in 1 file (checked 190 source files)

�[33mWARNING: You are using pip version 21.2.4; however, version 21.3.1 is available.
You should consider upgrading via the '/usr/local/bin/python -m pip install --upgrade pip' command.�[0m
torchvision/prototype/models/resnet.py:52: error: Name "blah" is not defined 
[name-defined]
                    f"Oops, you specified num_classes={blah} but this is i...
                    ^
torchvision/prototype/models/resnet.py:52: error: Name "blop" is not defined 
[name-defined]
                    f"Oops, you specified num_classes={blah} but this is i...
                    ^
Found 2 errors in 1 file (checked 190 source files)


Exited with code exit status 1

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[datumbox]

Thanks for the comments @NicolasHug.

I'm going to go ahead and implement many of the proposals and send a PR (I'll add you as reviewer).

I also added more comments/context to those that I require more clarifications. Let me know your thoughts.

[datumbox]

@NicolasHug I believe we addressed all the comments on this PR and we can close it. If there are more, happy to make the needed changes. Let me know

[NicolasHug]

Thanks for all the discussions @datumbox @fmassa , we can safely close this one now. Latest discussions were tracked in #4652 (comment)