[CI] draftversion checker

Introduce a new CI checker to ensure that draftversion fields are set
correctly.

.github/workflows/ci.yml

@@ -32,3 +32,12 @@ jobs:
     - uses: gaurav-nelson/github-action-markdown-link-check@v1
       with:
           config-file: '.github/workflows/markdown-link-check.json'
+
+  draftversion-check:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    - name: check correctness of draftversion fields
+      run:  python ./tools/acle_draftversion_value_check.py .

tools/acle_draftversion_value_check.py

@@ -0,0 +1,89 @@
+"""
+"
+" Copyright (C) 2023 Arm Ltd
+"
+"""
+
+from pathlib import Path
+import re
+import subprocess
+import sys
+
+
+def get_modified_file_list(repo_path: Path) -> list[str]:
+    """Use git to get the list of modified files in the patch set"""
+    starting_point = "origin/main"
+    cmd = ["git", "-C", str(repo_path), "diff", "--name-only", starting_point, "HEAD"]
+
+    try:
+        git_result = subprocess.run(args=cmd, capture_output=True, check=True)
+    except subprocess.CalledProcessError as ex:
+        print(
+            f"Error: in command '{' '.join(cmd)}':\n{ex.stderr.decode()}",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    modified_files = git_result.stdout.decode().split("\n")
+    modified_files = [x for x in modified_files if x]
+    return modified_files
+
+
+def check_file(file_path: Path) -> bool:
+    """Check if file has a draftversion field, and if so, that it's set to true"""
+    with file_path.open() as file:
+        print(f"Checking file {file_path}")
+        for line in file:
+            re_result = re.search(r"draftversion: (\w+)", line)
+            if not re_result:
+                continue
+
+            value = re_result[1]
+            if value != "true":
+                print(
+                    f"Error: file {file_path} has been modified but its draftversion"
+                    " isn't set to true!",
+                    file=sys.stderr,
+                )
+                return False
+
+    return True
+
+
+def main() -> int:
+    """Check if any modified file has the wrong value for draftversion"""
+    if len(sys.argv) != 2:
+        print(
+            "Error: this script takes a single positional argument, which is the path"
+            " to the ACLE repository!",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    try:
+        repo_path = Path(sys.argv[1]).resolve(strict=True)
+    except FileNotFoundError:
+        print(f"Error: repository {sys.argv[1]} doesn't exist!", file=sys.stderr)
+        sys.exit(1)
+
+    modified_files = get_modified_file_list(repo_path)
+    print("Files to check:")
+    if not modified_files:
+        print(" none")
+    else:
+        for path in modified_files:
+            print(f"  - {path}")
+    print()
+
+    success = True
+    for path in modified_files:
+        complete_path = repo_path / Path(path)
+        success = check_file(complete_path) and success
+
+    print("\nEnd result: " + ("OK" if success else "issues found"))
+
+    return not success
+
+
+if __name__ == "__main__":
+    sys.exit(main())