Copyright year precommit hook

Signed-off-by: Andrew Keesler <akeesler@vmware.com>

.pre-commit-config.yaml

@@ -15,3 +15,7 @@ repos:
   - id: detect-private-key
     exclude: testdata
   - id: mixed-line-ending
+- repo: .
+  rev: main
+  hooks:
+  - id: validate-copyright-year

.pre-commit-hooks.yaml

@@ -0,0 +1,4 @@
+- id: validate-copyright-year
+  name: Validate copyright year
+  entry: hack/check-copyright-year.sh
+  language: script

hack/check-copyright-year.sh

@@ -0,0 +1,21 @@
+#
+# Check if copyright statements include the current year
+#
+files=git diff --cached --name-only
+year=date +"%Y"
+
+for f in $files; do
+    head -10 $f | grep -i copyright 2>&1 1>/dev/null || continue
+
+    if ! grep -i -e "copyright.*$year" $f 2>&1 1>/dev/null; then
+        missing_copyright_files="$missing_copyright_files $f"
+    fi
+done
+
+if [ -n "$missing_copyright_files" ]; then
+    echo "$year is missing in the copyright notice of the following files:"
+    for f in $missing_copyright_files; do
+        echo "    $f"
+    done 
+    exit 1
+fi