ci: check if sources include license header

.github/workflows/continuous-integration.yml

@@ -28,6 +28,13 @@ jobs:
       - name: Format with clang-format
         run: .github/workflows/scripts/format_cpp.sh
 
+  CheckLicense:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Check if sources include the license header
+        run: .github/workflows/scripts/check_for_license.sh
+
   BuildAndTest:
     runs-on: ubuntu-latest
     strategy:

.github/workflows/scripts/check_for_license.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+print_and_exit() {
+    echo "Need to add license header to file $1"
+    exit 1
+}
+
+
+files=$(find ./compiler/{include,lib,src} -iregex '^.*\.\(cpp\|cc\|h\|hpp\)$')
+
+for file in $files
+do
+    cmp <(head -n 4 $file) <(echo "// Part of the Concrete Compiler Project, under the BSD3 License with Zama
+// Exceptions. See
+// https://github.com/zama-ai/homomorphizer/blob/master/LICENSE.txt for license
+// information.") || print_and_exit $file
+done
+
+files=$(find ./compiler/{include,lib,src} -iregex '^.*\.\(py\)$')
+
+for file in $files
+do
+    cmp <(head -n 2 $file) <(echo "#  Part of the Concrete Compiler Project, under the BSD3 License with Zama Exceptions.
+#  See https://github.com/zama-ai/homomorphizer/blob/master/LICENSE.txt for license information.") || print_and_exit $file
+done