feat: Add custom pre-commit hook to check for updated Copyright header

Signed-off-by: Benedetta Delfino <benedetta.delfino@arm.com>
Change-Id: Ic6a07ef12868673466a5db0cbce08015b9df4ffc

2 files changed, 42 insertions, 0 deletions

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b601b03..3788326 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -124,3 +124,11 @@ repos:
   hooks:
     - id: commitizen-branch
       args: [--rev-range, HEAD~1..HEAD]
+
+- repo: local
+  hooks:
+    - id: check-copyright-header
+      name: Check Copyright header years
+      entry: python pre_commit_hooks/check_copyright_header.py
+      language: python
+      verbose: true
diff --git a/pre_commit_hooks/check_copyright_header.py b/pre_commit_hooks/check_copyright_header.py
new file mode 100644
index 0000000..ded7675
--- /dev/null
+++ b/pre_commit_hooks/check_copyright_header.py
@@ -0,0 +1,34 @@
+# SPDX-FileCopyrightText: Copyright 2024, Arm Limited and/or its affiliates.
+# SPDX-License-Identifier: Apache-2.0
+"""Pre-commit hook that checks the current year is in the Copyright header of a file.
+
+If the header is out of date it will print a warning.
+"""
+import datetime
+import subprocess  # nosec
+
+
+class CopyrightHeaderChecker:
+    """Class that wraps the checker for the Copyright header."""
+
+    def check_files_have_updated_header(self, filenames: list) -> None:
+        """Check whether input files have the current year in the copyright string."""
+        current_year = str(datetime.datetime.now().year)
+        for filename in filenames:
+            with open(filename, encoding="utf-8") as file:
+                first_line = file.readline()
+                second_line = file.readline()
+            if filename.endswith(".md") and current_year not in second_line:
+                print(f"WARNING: The Copyright header of {filename} is out of date!")
+
+            if not filename.endswith(".md") and current_year not in first_line:
+                print(f"WARNING: The Copyright header of {filename} is out of date!")
+
+
+if __name__ == "__main__":
+    staged_files = (
+        subprocess.check_output(["git", "diff", "--cached", "--name-only"])  # nosec
+        .decode()
+        .splitlines()
+    )
+    CopyrightHeaderChecker().check_files_have_updated_header(filenames=staged_files)