[Enhancement] Add build_func for UPSAMPLE_LAYERS

[Junjun2016]

Motivation

Add build_func for UPSAMPLE_LAYERS

Modification

UPSAMPLE_LAYERS

BC-breaking (Optional)

Does the modification introduce changes that break the backward-compatibility of the downstream repos?
Not sure.

Use cases

• Before the PR

from mmcv.cnn import build_upsample_layer
build_upsample_layer(cfg, *args, **kwargs)

• After the PR

from mmcv.cnn.bricks.registry import UPSAMPLE_LAYERS
UPSAMPLE_LAYERS.build(cfg, *args, **kwargs)

[Junjun2016]

@xvjiarui

[codecov]

Codecov Report

Merging #1272 (4f4e31a) into master (54907a3) will increase coverage by 0.40%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1272      +/-   ##
==========================================
+ Coverage   68.42%   68.82%   +0.40%     
==========================================
  Files         160      161       +1     
  Lines       10610    10747     +137     
  Branches     1938     1972      +34     
==========================================
+ Hits         7260     7397     +137     
+ Misses       2975     2962      -13     
- Partials      375      388      +13     

Flag	Coverage Δ
unittests	68.82% <100.00%> (+0.40%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmcv/cnn/bricks/registry.py	100.00% <100.00%> (ø)
mmcv/cnn/bricks/upsample.py	100.00% <100.00%> (ø)
mmcv/utils/config.py	90.10% <0.00%> (-0.29%)	⬇️
mmcv/ops/psa_mask.py	31.81% <0.00%> (ø)
mmcv/runner/builder.py	100.00% <0.00%> (ø)
mmcv/utils/registry.py	98.31% <0.00%> (ø)
mmcv/runner/__init__.py	100.00% <0.00%> (ø)
mmcv/runner/hooks/__init__.py	100.00% <0.00%> (ø)
mmcv/runner/default_constructor.py	77.77% <0.00%> (ø)
mmcv/video/processing.py	77.41% <0.00%> (+0.37%)	⬆️
... and 7 more

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[zhouzaida]

LGTM

[ZwwWayne]

Should use UPSAMPLE_LAYERS.buil() here?

[Junjun2016]

Will lead to recursive import.

[ZwwWayne]

Then please leave a comment above this line of code.

[ZwwWayne]

Add docstring to indicates what is the difference between build_upsample_layer_from_cfg and build_from_cfg

[Junjun2016]

Since the interfaces of all UPSAMPLE_LAYERs modules are different.
I have added usage and deprecate information.

[Junjun2016]

I just wrap build_upsample_layer as a build_func (build_upsample_layer_from_cfg) and build_upsample_layer can be deprecated in the future.

[ZwwWayne]

1. The motivation of this PR is not clearly delivered through the PR message and the code comments/docstring. Does it want to deprecate build_upsample_layer or what? Please write accurate PR messages and add comments in the code docstring.
2. not sure is not an acceptable answer for the BC-breaking section. Please be responsible, think about it seriously, and answer it accurately.
3. The modification section is vague and inconsistent with the real code change. Please rephrase it.
4. Put build_upsample_layer_from_cfg in registry.py is not a good design to me, please re-think it.
5. This PR is closed as it dis-obey many rules. Please create a new PR with a better design and more serious/clear PR message. See a good example at [Feature] Add revert_sync_batchnorm #1253