Automate generating GitHub releases

Author: nicoddemus

.github/workflows/main.yml

@@ -53,12 +53,20 @@ jobs:
     - name: Install wheel
       run: |
         python -m pip install --upgrade pip
-        pip install wheel
+        pip install build
     - name: Build package
       run: |
-        python setup.py sdist bdist_wheel
+        python -m build
     - name: Publish package to PyPI
       uses: pypa/gh-action-pypi-publish@master
       with:
         user: __token__
         password: ${{ secrets.pypi_token }}
+    - name: Generate release notes
+      run: |
+        pip install pypandoc
+        python scripts/gen-release-notes.py
+    - name: GitHub Release
+      uses: softprops/action-gh-release@v1
+      with:
+        body_path: scripts/latest-release-notes.md

.gitignore

@@ -60,3 +60,4 @@ docs/_build/
 .idea
 .vscode
 /src/pytest_mock/_version.py
+scripts/latest-release-notes.md

scripts/gen-release-notes.py

@@ -0,0 +1,30 @@
+"""
+Generates the release notes for the latest release, in Markdown.
+
+Convert CHANGELOG.rst to Markdown, and extracts just the latest release.
+
+Writes to ``scripts/latest-release-notes.md``, which can be
+used with https://github.com/softprops/action-gh-release.
+"""
+from pathlib import Path
+
+import pypandoc
+
+this_dir = Path(__file__).parent
+rst_text = (this_dir.parent / "CHANGELOG.rst").read_text(encoding="UTF-8")
+md_text = pypandoc.convert_text(
+    rst_text, "md", format="rst", extra_args=["--wrap=preserve"]
+)
+
+output_lines = []
+first_heading_found = False
+for line in md_text.splitlines():
+    if line.startswith("# "):
+        if first_heading_found:
+            break
+        first_heading_found = True
+    output_lines.append(line)
+
+output_fn = this_dir / "latest-release-notes.md"
+output_fn.write_text("\n".join(output_lines), encoding="UTF-8")
+print(output_fn, "generated.")