Migrate from changelog_entry.yaml to towncrier fragments

.github/bump_version.py

@@ -0,0 +1,79 @@
+"""Infer semver bump from towncrier fragment types and update version."""
+
+import re
+import sys
+from pathlib import Path
+
+
+def get_current_version(pyproject_path: Path) -> str:
+    text = pyproject_path.read_text()
+    match = re.search(r'^version\s*=\s*"(\d+\.\d+\.\d+)"', text, re.MULTILINE)
+    if not match:
+        print(
+            "Could not find version in pyproject.toml",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+    return match.group(1)
+
+
+def infer_bump(changelog_dir: Path) -> str:
+    fragments = [
+        f
+        for f in changelog_dir.iterdir()
+        if f.is_file() and f.name != ".gitkeep"
+    ]
+    if not fragments:
+        print("No changelog fragments found", file=sys.stderr)
+        sys.exit(1)
+
+    categories = {f.suffix.lstrip(".") for f in fragments}
+    for f in fragments:
+        parts = f.stem.split(".")
+        if len(parts) >= 2:
+            categories.add(parts[-1])
+
+    if "breaking" in categories:
+        return "major"
+    if "added" in categories or "removed" in categories:
+        return "minor"
+    return "patch"
+
+
+def bump_version(version: str, bump: str) -> str:
+    major, minor, patch = (int(x) for x in version.split("."))
+    if bump == "major":
+        return f"{major + 1}.0.0"
+    elif bump == "minor":
+        return f"{major}.{minor + 1}.0"
+    else:
+        return f"{major}.{minor}.{patch + 1}"
+
+
+def update_file(path: Path, old_version: str, new_version: str):
+    text = path.read_text()
+    updated = text.replace(
+        f'version = "{old_version}"',
+        f'version = "{new_version}"',
+    )
+    if updated != text:
+        path.write_text(updated)
+        print(f"  Updated {path}")
+
+
+def main():
+    root = Path(__file__).resolve().parent.parent
+    pyproject = root / "pyproject.toml"
+    changelog_dir = root / "changelog.d"
+
+    current = get_current_version(pyproject)
+    bump = infer_bump(changelog_dir)
+    new = bump_version(current, bump)
+
+    print(f"Version: {current} -> {new} ({bump})")
+
+    update_file(pyproject, current, new)
+
+
+if __name__ == "__main__":
+    main()

.github/workflows/pr_changelog.yaml

@@ -1,30 +1,21 @@
 name: Changelog entry
+
 on:
   pull_request:
     branches: [main]
 
 jobs:
-  check-fork:
+  check-changelog:
+    name: Check changelog fragment
     runs-on: ubuntu-latest
     steps:
-      - name: Check if PR is from fork
+      - uses: actions/checkout@v4
+      - name: Check for changelog fragment
         run: |
-          if [ "${{ github.event.pull_request.head.repo.full_name }}" != "${{ github.repository }}" ]; then
-            echo "❌ ERROR: This PR is from a fork repository."
-            echo "PRs must be created from branches in the main PolicyEngine/policyengine-us-data repository."
-            echo "Please close this PR and create a new one following these steps:"
-            echo "1. git checkout main"
-            echo "2. git pull upstream main"
-            echo "3. git checkout -b your-branch-name"
-            echo "4. git push -u upstream your-branch-name"
-            echo "5. Create PR from the upstream branch"
+          FRAGMENTS=$(find changelog.d -type f ! -name '.gitkeep' | wc -l)
+          if [ "$FRAGMENTS" -eq 0 ]; then
+            echo "::error::No changelog fragment found in changelog.d/"
+            echo "Add one with: echo 'Description.' > changelog.d/\$(git branch --show-current).<type>.md"
+            echo "Types: added, changed, fixed, removed, breaking"
             exit 1
           fi
-          echo "✅ PR is from the correct repository"
-
-  require-entry:
-    needs: check-fork
-    uses: ./.github/workflows/reusable_changelog_check.yaml
-    with:
-      require_entry: true
-      validate_format: true

.github/workflows/versioning.yaml

@@ -7,7 +7,7 @@ on:
           - main
 
       paths:
-        - changelog_entry.yaml
+        - "changelog.d/**"
         - "!pyproject.toml"
 
 jobs:
@@ -19,20 +19,23 @@ jobs:
             uses: actions/checkout@v4
             with:
               token: ${{ secrets.POLICYENGINE_GITHUB }}
+              fetch-depth: 0
           - name: Setup Python
             uses: actions/setup-python@v5
             with:
               python-version: 3.12
           - name: Install uv
             uses: astral-sh/setup-uv@v5
-          - name: Build changelog
-            run: pip install yaml-changelog && make changelog
+          - name: Install towncrier
+            run: pip install towncrier
+          - name: Bump version and build changelog
+            run: |
+              python .github/bump_version.py
+              towncrier build --yes --version $(python -c "import re; print(re.search(r'version = \"(.+?)\"', open('pyproject.toml').read()).group(1))")
           - name: Update lockfile
             run: uv lock
-          - name: Preview changelog update
-            run: ".github/get-changelog-diff.sh"
           - name: Update changelog
             uses: EndBug/add-and-commit@v9
             with:
               add: "."
-              message: Update package version
+              message: Update package version

Makefile

@@ -15,12 +15,8 @@ install:
 	pip install -e ".[dev]"  --config-settings editable_mode=compat
 
 changelog:
-	build-changelog changelog.yaml --output changelog.yaml --update-last-date --start-from 1.0.0 --append-file changelog_entry.yaml
-	build-changelog changelog.yaml --org PolicyEngine --repo policyengine-us-data --output CHANGELOG.md --template .github/changelog_template.md
-	bump-version changelog.yaml pyproject.toml
-	rm changelog_entry.yaml || true
-	touch changelog_entry.yaml
-
+	python .github/bump_version.py
+	towncrier build --yes --version $$(python -c "import re; print(re.search(r'version = \"(.+?)\"', open('pyproject.toml').read()).group(1))")
 download:
 	python policyengine_us_data/storage/download_private_prerequisites.py
 

changelog.d/migrate-to-towncrier.changed.md

@@ -0,0 +1 @@
+Migrated from changelog_entry.yaml to towncrier fragments to eliminate merge conflicts.

pyproject.toml

@@ -65,7 +65,8 @@ dev = [
     "yaml-changelog>=0.1.7",
     "build",
     "tomli",
-    "itables",
+    "itables",    "towncrier>=24.8.0",
+
 ]
 
 [tool.setuptools]
@@ -98,3 +99,36 @@ extend-exclude = '''
   | dist
 )/
 '''
+
+[tool.towncrier]
+package = "policyengine_us_data"
+directory = "changelog.d"
+filename = "CHANGELOG.md"
+title_format = "## [{version}] - {project_date}"
+issue_format = ""
+underlines = ["", "", ""]
+
+[[tool.towncrier.type]]
+directory = "breaking"
+name = "Breaking changes"
+showcontent = true
+
+[[tool.towncrier.type]]
+directory = "added"
+name = "Added"
+showcontent = true
+
+[[tool.towncrier.type]]
+directory = "changed"
+name = "Changed"
+showcontent = true
+
+[[tool.towncrier.type]]
+directory = "fixed"
+name = "Fixed"
+showcontent = true
+
+[[tool.towncrier.type]]
+directory = "removed"
+name = "Removed"
+showcontent = true