Use setuptools_scm (#48)

* Use setuptools_scm

Follows up #47

- on [pypi](https://pypi.org/project/torchsampler/0.1.1/) it's 0.1.1
- on github it's [0.1.0](https://github.com/ufoym/imbalanced-dataset-sampler/releases/tag/v0.1.0)
    - but the attached [wheel](https://github.com/ufoym/imbalanced-dataset-sampler/releases/download/v0.1.0/torchsampler-0.1.1-py3-none-any.whl)
      and [sdist](https://github.com/ufoym/imbalanced-dataset-sampler/releases/download/v0.1.0/torchsampler-0.1.1.tar.gz) are 0.1.1

[`setuptools-scm`](https://pypi.org/project/setuptools-scm/) makes git the single-source of truth
for the version of the package, and works well with the build script in #47 (which is triggered
by tagging a new version in git).

`setuptools-scm` also replaces most of MANIFEST.in, so this removes the
redundant lines from that too.

* Deprecate torchsampler.__about__

It's better to keep all metadata in setup.py and use importlib.metadata.
Otherwise, you need to 'import __about__' during the build process
means importlib-metadata needs to be installed during the build
if building on python 3.6 or python 3.7, and potentially running an
unbounded amount of other code during the build.

It's easier to just sidestep the issue.

* Squash a build warning

> .../site-packages/setuptools/dist.py:726: UserWarning: Usage of dash-separated 'description-file' will not be supported in future versions. Please use the underscore name 'description_file' instead

description_file has been superseded recently in
4c4a6e3 anyway.

.github/workflows/ci_install-pkg.yml

@@ -19,8 +19,6 @@ jobs:
 
       - name: Check package
         run: |
-          pip install check-manifest
-          check-manifest
           python setup.py check --metadata --strict
 
       - name: Create package

MANIFEST.in

@@ -1,24 +1,11 @@
-# Manifest syntax https://docs.python.org/2/distutils/sourcedist.html
-graft wheelhouse
+# Manifest syntax https://setuptools.pypa.io/en/latest/deprecated/distutils/commandref.html#sdist-cmd
 
-recursive-exclude __pycache__  *.py[cod] *.orig
-
-# Include the README
-include *.md
-
-# Include the license file
-include LICENSE
-
-recursive-include torchsampler *.py
-
-# Include the Requirements
-include requirements.txt
+# FIXME: switching to a src/ layout would obviate the need for this file entirely.
+#        see https://setuptools.pypa.io/en/latest/userguide/package_discovery.html#src-layout
 
 # Exclude build configs
 exclude *.yml
 exclude *.yaml
 
 prune .github
 prune example*
-prune temp*
-prune test*

requirements.txt

@@ -1,3 +1,5 @@
 torch>=1.3
 torchvision>=0.5
 pandas
+# only needed by __about__.py, which is deprecated:
+importlib_metadata; python_version<'3.8'

setup.cfg

@@ -1,6 +1,5 @@
 [metadata]
 license_file = LICENSE
-description-file = README.md
 
 [flake8]
 max-line-length = 120

setup.py

@@ -1,17 +1,9 @@
 """A setuptools based setup module."""
 
-import sys
 from pathlib import Path
 
 from setuptools import setup
 
-try:
-    from torchsampler import __about__ as about
-except ImportError:
-    # alternative https://stackoverflow.com/a/67692/4521646
-    sys.path.append("torchsampler")
-    import __about__ as about
-
 PATH_HERE = Path(__file__).parent
 
 with open(PATH_HERE / 'requirements.txt', encoding='utf-8') as fp:
@@ -20,16 +12,18 @@
 
 setup(
     name='torchsampler',
-    version=about.__version__,
-    url=about.__homepage__,
-    author=about.__author__,
-    author_email=about.__author_email__,
-    license=about.__license__,
-    description=about.__doc__,
+    use_scm_version=True,
+    url="https://github.com/ufoym/imbalanced-dataset-sample",
+    author="Ming, et al.",
+    author_email="[email protected]",
+    license="MIT",
+    description="A (PyTorch) imbalanced dataset sampler for oversampling low classes"
+    "and undersampling high frequent ones.",
     long_description=long_description,
     long_description_content_type='text/markdown',
     packages=['torchsampler'],
     keywords='sampler,pytorch,dataloader',
+    setup_requires=['setuptools_scm'],
     install_requires=requirements,
     python_requires='>=3.6',
     include_package_data=True,

torchsampler/__about__.py

@@ -1,10 +1,31 @@
-__version__ = "0.1.1"
-__author__ = "Ming, et al."
-__author_email__ = "[email protected]"
-__license__ = "MIT"
-__homepage__ = "https://github.com/ufoym/imbalanced-dataset-sampler"
-__doc__ = "A (PyTorch) imbalanced dataset sampler for oversampling low frequent classes" \
-          " and undersampling high frequent ones."
+import sys
+
+if sys.version_info < (3, 8):
+    from importlib_metadata import distribution, PackageNotFoundError
+else:
+    from importlib.metadata import distribution, PackageNotFoundError
+
+import warnings
+
+warnings.warn(
+    "Use importlib.metadata.distribution('torchsampler').metadata instead of torchsampler.__about__.",
+    category=DeprecationWarning
+)
+
+try:
+    _m = distribution('torchsampler').metadata
+    __version__ = _m['version']
+    __author__ = _m['author']
+    __author_email__ = _m['author-email']
+    __license__ = _m['license']
+    __homepage__ = _m['homepage']
+    __doc__ = _m['summary']
+    del _m
+except PackageNotFoundError:
+    # package is not installed (i.e. we're probably in the build process itself)
+    pass
+
+del sys, distribution, PackageNotFoundError, warnings
 
 __all__ = [
     "__author__",