Check that all xml files in CDT are well formed

.github/workflows/code-cleanliness.yml

@@ -16,7 +16,7 @@ jobs:
           image: quay.io/eclipse-cdt/cdt-infra-github@sha256:3d745b7b84e3f9f9492cc1d280ea3b44028a92c7e9748d1ea8771fed211b5dc4
           options: -v ${{ github.workspace }}:/work
           run: |
-            set -x
+            set -ex
             cd /work
             ./releng/scripts/check_code_cleanliness_only.sh
             ./releng/scripts/check_bundle_versions.sh

releng/scripts/check_code_cleanliness_only.sh

@@ -56,3 +56,9 @@ echo "sure no dependencies on unexpected or newer libraries are accidentally"
 echo "introduced."
 ${DIR}/check_dll_dependencies.sh
 ${DIR}/check_glibc_dependencies.sh
+
+##
+# Error out if some XML files are badly formed
+##
+DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+${DIR}/check_xml_well_formed.sh

releng/scripts/check_xml_well_formed.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+###############################################################################
+# Copyright (c) 2020, 2025 Kichwa Coders Canada Inc and others.
+#
+# This program and the accompanying materials
+# are made available under the terms of the Eclipse Public License 2.0
+# which accompanies this distribution, and is available at
+# https://www.eclipse.org/legal/epl-2.0/
+#
+# SPDX-License-Identifier: EPL-2.0
+###############################################################################
+
+set -eu
+
+exit_code=0
+while read line; do
+    if ! xmllint $line > /dev/null; then
+        echo $line has badly formed XML;
+        exit_code=1
+    fi
+done <<<$(git ls-files '**/*.xml')
+
+exit ${exit_code}