Use setuptools_scm to produce a version number dynamically (#97)

This will generate a version number automatically from tags in the
repository. It will also produce a distinct development tag for each
commit we make to the repository. This allows pushing intermediate
package snapshots to TestPyPI in between official tags.

Author: ldionne

.github/workflows/build-and-publish-package.yml

@@ -11,6 +11,7 @@ jobs:
     steps:
     - uses: actions/checkout@v5
       with:
+        fetch-depth: 0 # fetch all history including tags -- necessary to determine the version from SCM
         persist-credentials: false
     - name: Set up Python
       uses: actions/setup-python@v5
@@ -29,8 +30,7 @@ jobs:
 
   publish-to-testpypi:
     runs-on: ubuntu-latest
-    if: startsWith(github.ref, 'refs/tags/') # only publish to test.PyPI on tag pushes (for the time being)
-    # if: github.event_name == 'push' && github.ref == 'refs/heads/main' # only publish to test.PyPI on pushes to main
+    if: github.event_name == 'push' && github.ref == 'refs/heads/main' # only publish to test.PyPI on pushes to main
 
     name: Publish LNT to TestPyPI
     needs: [build]

.github/workflows/build-docker.yaml

@@ -18,6 +18,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      with:
+        fetch-depth: 0 # fetch all history including tags -- necessary to determine the version from SCM
 
     - name: Log in to the Container registry
       uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef
@@ -32,3 +34,4 @@ jobs:
       with:
         push: ${{ github.event_name == 'push' }}
         tags: ghcr.io/${{github.repository}}:latest
+        context: . # use the current directory as context, as checked out by actions/checkout -- needed for setuptools_scm

.github/workflows/tox.yaml

@@ -15,6 +15,8 @@ jobs:
 
     steps:
     - uses: actions/checkout@v5
+      with:
+        fetch-depth: 0 # fetch all history including tags -- necessary to determine the version from SCM
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v6
       with:

pyproject.toml

@@ -1,10 +1,10 @@
 [build-system]
-requires = ["setuptools >= 74.1"]
+requires = ["setuptools>=80", "setuptools-scm>=8"]
 build-backend = "setuptools.build_meta"
 
 [project]
 name = "llvm-lnt"
-version = "0.4.3"
+dynamic = ["version"]
 description = "LLVM Nightly Test Infrastructure"
 readme = "README.md"
 license = "LicenseRef-Apache-2.0-with-LLVM-exception"
@@ -98,6 +98,9 @@ find = {namespaces = false}
     "migrations/*.py"
 ]
 
+[tool.setuptools_scm]
+# This section is needed with older versions of Python, although it can be empty.
+
 [tool.flake8]
 ignore = ["E712", "E402", "E711", "E266", "W605", "E126", "E226", "W504"]
 max-line-length = 120