Automate creating releases from Changelog and add Changelog to docs

.github/workflows/release.yml

@@ -0,0 +1,28 @@
+name: Create GitHub release
+
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+
+permissions:
+  contents: write
+
+jobs:
+  create-release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Extract changelog for this version
+        run: |
+          VERSION="${{ github.ref_name }}"
+          python3 build_support/releases/extract_changelog.py "${VERSION#v}"
+
+      - name: Create GitHub release
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          gh release create "${{ github.ref_name }}" \
+            --title "Gambit ${{ github.ref_name }}" \
+            --notes-file release_notes.md

ChangeLog

@@ -1,5 +1,3 @@
-# Changelog
-
 ## [16.7.0] - unreleased
 
 ### Added

build_support/releases/extract_changelog.py

@@ -0,0 +1,81 @@
+"""Extract the changelog section for a given version from the ChangeLog file.
+
+The ChangeLog at the repository root follows the Keep a Changelog format
+(https://keepachangelog.com). Each release section looks like:
+
+    ## [X.Y.Z] - YYYY-MM-DD
+
+    ### Added
+    - ...
+
+    ### Fixed
+    - ...
+
+This script locates the section for a given version and writes it to an output
+file, which is then used by the ``release.yml`` GitHub Actions workflow to
+populate the GitHub release notes.
+
+Usage
+-----
+Run from the repository root::
+
+    python build_support/releases/extract_changelog.py X.Y.Z
+
+Optional arguments::
+
+    --changelog PATH   Path to the ChangeLog file (default: ChangeLog)
+    --output PATH      Path to write extracted notes (default: release_notes.md)
+"""
+
+import argparse
+import pathlib
+import re
+import sys
+
+
+def extract(version: str, changelog: pathlib.Path, output: pathlib.Path) -> None:
+    """Extract the release notes for *version* from *changelog* and write to *output*.
+
+    Searches for a section header of the form ``## [X.Y.Z] - ...`` and captures
+    everything up to the next version header (or end of file).  Exits with a
+    non-zero status and an error message if the version is not found.
+
+    Parameters
+    ----------
+    version:
+        Version string without a leading ``v``, e.g. ``"16.6.0"``.
+    changelog:
+        Path to the ChangeLog file to read from.
+    output:
+        Path to the file to write the extracted notes to.
+    """
+    text = changelog.read_text()
+    pattern = re.compile(
+        rf"^## \[{re.escape(version)}\][^\n]*\n(.*?)(?=^## \[|\Z)",
+        re.MULTILINE | re.DOTALL,
+    )
+    match = pattern.search(text)
+    if not match:
+        print(f"No ChangeLog entry found for version {version}", file=sys.stderr)
+        sys.exit(1)
+    output.write_text(match.group(1).strip())
+    print(f"Extracted release notes for {version}")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("version", help="Version string, e.g. 16.6.0")
+    parser.add_argument(
+        "--changelog",
+        type=pathlib.Path,
+        default=pathlib.Path("ChangeLog"),
+        help="Path to the ChangeLog file (default: ChangeLog)",
+    )
+    parser.add_argument(
+        "--output",
+        type=pathlib.Path,
+        default=pathlib.Path("release_notes.md"),
+        help="Path to write the extracted notes (default: release_notes.md)",
+    )
+    args = parser.parse_args()
+    extract(args.version, args.changelog, args.output)

build_support/releases/test_extract_changelog.py

@@ -0,0 +1,171 @@
+"""Tests for extract_changelog.py.
+
+Covers two concerns:
+1. Correctness of the extraction logic (unit tests against fixture content).
+2. Format validity of the repository's actual ChangeLog file.
+
+The format tests act as a CI guard: if a contributor adds a malformed version
+header or an unrecognised section type to ChangeLog, the test suite will fail.
+"""
+
+import pathlib
+import re
+
+import pytest
+from extract_changelog import extract
+
+# ---------------------------------------------------------------------------
+# Paths
+# ---------------------------------------------------------------------------
+
+REPO_ROOT = pathlib.Path(__file__).parent.parent.parent
+CHANGELOG = REPO_ROOT / "ChangeLog"
+
+# ---------------------------------------------------------------------------
+# ChangeLog format rules (Keep a Changelog)
+# ---------------------------------------------------------------------------
+
+# Pre-release suffixes (a1, b2, rc3) follow PEP 440 conventions used in this project.
+VERSION_HEADER_RE = re.compile(
+    r"^## \[\d+\.\d+\.\d+(?:a\d+|b\d+|rc\d+)?\] - (\d{4}-\d{2}-\d{2}|unreleased)$"
+)
+# 'General' is a project-specific extension used for cross-cutting changes.
+SECTION_HEADER_RE = re.compile(r"^### (Added|Changed|Deprecated|Removed|Fixed|Security|General)$")
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+SAMPLE_CHANGELOG = """\
+# Changelog
+
+## [2.0.0] - 2024-01-15
+
+### Added
+- Feature A
+
+### Fixed
+- Bug B
+
+## [1.0.0] - 2023-06-01
+
+### Added
+- Initial release
+"""
+
+UNRELEASED_CHANGELOG = (
+    """\
+# Changelog
+
+## [3.0.0] - unreleased
+
+### Added
+- Upcoming feature
+
+"""
+    + SAMPLE_CHANGELOG
+)
+
+
+# ---------------------------------------------------------------------------
+# Extraction unit tests
+# ---------------------------------------------------------------------------
+
+
+def test_extract_known_version(tmp_path):
+    changelog = tmp_path / "ChangeLog"
+    changelog.write_text(SAMPLE_CHANGELOG)
+    output = tmp_path / "notes.md"
+
+    extract("2.0.0", changelog, output)
+
+    content = output.read_text()
+    assert "Feature A" in content
+    assert "Bug B" in content
+
+
+def test_extract_does_not_bleed_into_next_version(tmp_path):
+    changelog = tmp_path / "ChangeLog"
+    changelog.write_text(SAMPLE_CHANGELOG)
+    output = tmp_path / "notes.md"
+
+    extract("2.0.0", changelog, output)
+
+    assert "Initial release" not in output.read_text()
+
+
+def test_extract_last_version_in_file(tmp_path):
+    changelog = tmp_path / "ChangeLog"
+    changelog.write_text(SAMPLE_CHANGELOG)
+    output = tmp_path / "notes.md"
+
+    extract("1.0.0", changelog, output)
+
+    assert "Initial release" in output.read_text()
+
+
+def test_extract_unreleased_version(tmp_path):
+    changelog = tmp_path / "ChangeLog"
+    changelog.write_text(UNRELEASED_CHANGELOG)
+    output = tmp_path / "notes.md"
+
+    extract("3.0.0", changelog, output)
+
+    assert "Upcoming feature" in output.read_text()
+
+
+def test_extract_missing_version_exits(tmp_path):
+    changelog = tmp_path / "ChangeLog"
+    changelog.write_text(SAMPLE_CHANGELOG)
+    output = tmp_path / "notes.md"
+
+    with pytest.raises(SystemExit) as exc_info:
+        extract("99.0.0", changelog, output)
+
+    assert exc_info.value.code != 0
+
+
+def test_extract_output_is_stripped(tmp_path):
+    changelog = tmp_path / "ChangeLog"
+    changelog.write_text(SAMPLE_CHANGELOG)
+    output = tmp_path / "notes.md"
+
+    extract("2.0.0", changelog, output)
+
+    content = output.read_text()
+    assert content == content.strip()
+
+
+# ---------------------------------------------------------------------------
+# ChangeLog format validation tests
+# ---------------------------------------------------------------------------
+
+
+def _changelog_lines():
+    """Return (line_number, line) pairs for the repository ChangeLog."""
+    return list(enumerate(CHANGELOG.read_text().splitlines(), start=1))
+
+
+@pytest.mark.parametrize(
+    "lineno,line",
+    [(line_number, line) for line_number, line in _changelog_lines() if line.startswith("## ")],
+)
+def test_version_header_format(lineno, line):
+    """Every '## ' line must match '## [X.Y.Z] - YYYY-MM-DD' or '## [X.Y.Z] - unreleased'."""
+    assert VERSION_HEADER_RE.match(line), (
+        f"ChangeLog line {lineno}: invalid version header: {line!r}\n"
+        "Expected: ## [X.Y.Z] - YYYY-MM-DD  or  ## [X.Y.Z] - unreleased"
+    )
+
+
+@pytest.mark.parametrize(
+    "lineno,line",
+    [(line_number, line) for line_number, line in _changelog_lines() if line.startswith("### ")],
+)
+def test_section_header_type(lineno, line):
+    """Every '### ' line must be one of the recognised Keep a Changelog types."""
+    assert SECTION_HEADER_RE.match(line), (
+        f"ChangeLog line {lineno}: unrecognised section header: {line!r}\n"
+        "Allowed: ### Added, ### Changed, ### Deprecated, "
+        "### Removed, ### Fixed, ### Security"
+    )

doc/conf.py

@@ -49,6 +49,7 @@
     "sphinxcontrib.tikz",
     "jupyter_sphinx",
     "sphinxcontrib.bibtex",
+    "myst_parser",
 ]
 
 
@@ -212,7 +213,7 @@ def get_techreport_template(self, e):
 templates_path = ["_templates"]
 
 # The suffix of source filenames.
-source_suffix = ".rst"
+source_suffix = {".rst": "restructuredtext", ".md": "markdown"}
 
 # The encoding of source files.
 # source_encoding = 'utf-8'
@@ -240,6 +241,11 @@ def get_techreport_template(self, e):
     # Throw error if GAMBIT_VERSION file not found
     raise FileNotFoundError("GAMBIT_VERSION file not found")
 
+_release_url = f"https://github.com/gambitproject/gambit/releases/tag/v{_full_version}"
+rst_epilog = f"""
+.. |release_link| replace:: `GitHub releases page <{_release_url}>`__
+"""
+
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 # language = None

doc/developer.contributing.rst

@@ -280,7 +280,19 @@ When making a new release of Gambit, follow these steps:
    - `doc/conf.py` reads from GAMBIT_VERSION file at documentation build time
    - Documentation pages reference the `|release|` substitution variable to automatically reflect the updated version number.
 
-3. Update the `ChangeLog` file with a summary of changes
+3. Update the ``ChangeLog`` file at the repository root with a summary of changes for this release.
+   This file is the single source of truth for release notes — it is surfaced in the documentation
+   (see :ref:`releases`) and used to populate the GitHub release automatically.
+
+   The ``ChangeLog`` must follow the `Keep a Changelog <https://keepachangelog.com>`__ format:
+   version headers of the form ``## [X.Y.Z] - YYYY-MM-DD`` and subsections from
+   ``Added``, ``Changed``, ``Deprecated``, ``Removed``, ``Fixed``, or ``Security``.
+   The test suite enforces this format — any malformed entry will cause ``pytest`` to fail.
+
+   To verify the new entry will be extracted correctly before tagging, run the
+   extraction script from the repository root::
+
+       python build_support/releases/extract_changelog.py X.Y.Z
 
 4. Once there are no further commits to be made for the release, create a tag for the release from the latest commit on the maintenance branch. ::
 
@@ -291,8 +303,10 @@ When making a new release of Gambit, follow these steps:
     git push origin maintX_Y
     git push origin --tags
 
-6. Create a new release on the `GitHub releases page <https://github.com/gambitproject/gambit/releases>`__, using the tag created in step 4.
-   Include a summary of changes from the `ChangeLog` file in the release notes.
+6. Pushing the tag triggers the ``release.yml`` GitHub Actions workflow, which automatically
+   reads the ``ChangeLog`` entry for the new version and creates the corresponding release on the
+   `GitHub releases page <https://github.com/gambitproject/gambit/releases>`__ with those notes.
+   No manual action is required.
 
 7. Currently there is no automated process for pushing the new release to PyPI. This must be done manually.
 

doc/index.rst

@@ -21,7 +21,6 @@ construction and analysis of finite extensive and strategic games.
          :color: secondary
          :expand:
 
-
    .. grid-item-card:: 🐍 PyGambit
       :columns: 3