ci: check extension versions are updated if changed (#929)

Based on CQCL/hugr#2364

See commits 2 and 3 for demo

Author: ss2165

.github/change-filters.yml

@@ -19,3 +19,6 @@ python:
   - "tket2-exts/**"
   - "pyproject.toml"
   - "uv.lock"
+
+extensions:
+  - "tket2-exts/src/tket2_exts/data/tket2/**"

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ env:
 
 jobs:
   # Check if changes were made to the relevant files.
-  # Always returns true if running on the default branch, to ensure all changes are throughly checked.
+  # Always returns true if running on the default branch, to ensure all changes are thoroughly checked.
   changes:
     name: Check for changes
     runs-on: ubuntu-latest
@@ -43,6 +43,7 @@ jobs:
     outputs:
       rust: ${{ steps.filter.outputs.rust == 'true' || steps.override.outputs.out == 'true' }}
       python: ${{ steps.filter.outputs.python == 'true' || steps.override.outputs.out == 'true' }}
+      extensions: ${{ steps.filter.outputs.extensions == 'true' || steps.override.outputs.out == 'true' }}
     steps:
     - uses: actions/checkout@v4
     - name: Override label
@@ -308,12 +309,36 @@ jobs:
             "
             exit 1
           fi
+  extension-versions:
+    runs-on: ubuntu-latest
+    needs: [changes]
+    if: ${{ needs.changes.outputs.extensions == 'true' }}
+    name: Check extension versions
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0  # Need full history to compare with main
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+
+      - name: Check if extension versions are updated
+        # check against latest tag on the target branch
+        # base_ref should be empty if not a pull request, so goes from HEAD
+        run: |
+            BASE_SHA=$(git rev-parse origin/${{ github.base_ref }})
+            LAST_TAG=$(git describe --abbrev=0 --match="tket2-*" $BASE_SHA)
+            echo "Latest tag on target: $LAST_TAG"
+            
+            python ./scripts/check_extension_versions.py $LAST_TAG
 
   # This is a meta job to mark successful completion of the required checks,
   # even if they are skipped due to no changes in the relevant files.
   required-checks:
     name: Required checks 🦀+🐍
-    needs: [changes, check-rs, check-py, tests-rs-stable-no-features, tests-rs-stable-all-features, tests-py, tket2-extensions]
+    needs: [changes, check-rs, check-py, tests-rs-stable-no-features, tests-rs-stable-all-features, tests-py, tket2-extensions, extension-versions]
     if: ${{ !cancelled() }}
     runs-on: ubuntu-latest
     steps:

scripts/check_extension_versions.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python
+
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+
+def get_changed_files(target: str) -> list[Path]:
+    """Get list of changed extension files in the PR"""
+    # Use git to get the list of files changed compared to target
+    cmd = [
+        "git",
+        "diff",
+        "--name-only",
+        target,
+        "--",
+        "tket2-exts/src/tket2_exts/data/tket2/",
+    ]
+    result = subprocess.run(cmd, capture_output=True, text=True, check=True)  # noqa: S603
+    changed_files = [Path(f) for f in result.stdout.splitlines() if f.endswith(".json")]
+    return changed_files
+
+
+def check_version_changes(changed_files: list[Path], target: str) -> list[str]:
+    """Check if versions have been updated in changed files"""
+    errors = []
+
+    for file_path in changed_files:
+        # Skip files that don't exist anymore (deleted files)
+        if not file_path.exists():
+            continue
+
+        # Get the version in the current branch
+        with file_path.open("r") as f:
+            current = json.load(f)
+            current_version = current.get("version")
+
+        # Get the version in the target branch
+        try:
+            cmd = ["git", "show", f"{target}:{file_path}"]
+            result = subprocess.run(cmd, capture_output=True, text=True)  # noqa: S603
+
+            if result.returncode == 0:
+                # File exists in target
+                target_content = json.loads(result.stdout)
+                target_version = target_content.get("version")
+
+                if current_version == target_version:
+                    errors.append(
+                        f"Error: {file_path} was modified but version {current_version} was not updated."
+                    )
+                else:
+                    print(
+                        f"Version updated in {file_path}: {target_version} -> {current_version}"
+                    )
+
+            else:
+                # New file - no version check needed
+                pass
+
+        except json.JSONDecodeError:
+            # File is new or not valid JSON in target
+            pass
+
+    return errors
+
+
+def main() -> int:
+    target = sys.argv[1] if len(sys.argv) > 1 else "origin/main"
+    changed_files = get_changed_files(target)
+    if not changed_files:
+        print("No extension files changed.")
+        return 0
+
+    print(f"Changed extension files: {', '.join(map(str, changed_files))}")
+
+    errors = check_version_changes(changed_files, target)
+    if errors:
+        for error in errors:
+            print(error)
+        return 1
+
+    print("All changed extension files have updated versions.")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())