Attempt to set Python package version to the snapshot identifier.

This should make the releases sort properly when `pip`'s
`-f`/`--find-links` argument is used.

.github/workflows/buildAndTest.yml

@@ -10,6 +10,9 @@ on:
       release_id:
         description: 'Release id to upload artifacts to'
         default: ''
+      python_package_version:
+        description: 'Version to use for creating the Python package'
+        default: ''
 
 jobs:
   build:
@@ -79,6 +82,7 @@ jobs:
         python -m pip install wheel
         TORCH_MLIR_CMAKE_BUILD_DIR="$GITHUB_WORKSPACE/build" \
           TORCH_MLIR_CMAKE_BUILD_DIR_ALREADY_BUILT=1 \
+          TORCH_MLIR_PYTHON_PACKAGE_VERSION="${{ github.event.inputs.python_package_version }}" \
           ./build_tools/build_python_wheels.sh
 
     # If we were given a release_id, then upload the package we just built

.github/workflows/releaseSnapshotPackage.yml

@@ -56,4 +56,4 @@ jobs:
           workflow: Build and Test
           token: ${{ secrets.WORKFLOW_INVOCATION_TOKEN }}
           ref: "${{ env.tag_name }}"
-          inputs: '{"release_id": "${{ steps.create_release.outputs.id }}"}'
+          inputs: '{"release_id": "${{ steps.create_release.outputs.id }}", "python_package_version": "${{ env.package_version }}"}'

setup.py

@@ -20,6 +20,10 @@
 # prevent this script from attempting to build the directory, and will simply
 # use the (presumed already built) directory as-is.
 #
+# The package version can be set with the TORCH_MLIR_PYTHON_PACKAGE_VERSION
+# environment variable. For example, this can be "20220330.357" for a snapshot
+# release on 2022-03-30 with build number 357.
+#
 # Implementation notes:
 # The contents of the wheel is just the contents of the `python_packages`
 # directory that our CMake build produces. We go through quite a bit of effort
@@ -35,6 +39,7 @@ from setuptools import setup, Extension
 from setuptools.command.build_ext import build_ext
 from setuptools.command.build_py import build_py
 
+PACKAGE_VERSION = os.environ.get("TORCH_MLIR_PYTHON_PACKAGE_VERSION") or "0.0.1"
 
 # Build phase discovery is unreliable. Just tell it what phases to run.
 class CustomBuild(_build):
@@ -108,7 +113,7 @@ class NoopBuildExtension(build_ext):
 
 setup(
     name="torch-mlir",
-    version="0.0.1",
+    version=f"{PACKAGE_VERSION}",
     author="Sean Silva",
     author_email="silvasean@google.com",
     description="First-class interop between PyTorch and MLIR",