container: Ensure mount sources and destinations are unique

roles/container/tasks/main.yaml

@@ -1,4 +1,7 @@
 ---
+- name: Validate inputs
+  ansible.builtin.import_tasks: validation.yaml
+
 - name: Create networks for container {{ container_name }}
   ansible.builtin.include_role:
     name: network

roles/container/tasks/validation.yaml

@@ -0,0 +1,8 @@
+---
+- name: Assert mount sources and destinations are unique
+  ansible.builtin.assert:
+    that:
+      - _container_mount_destinations | unique | length == _container_mount_destinations | length
+      - _container_mount_sources | unique | length == _container_mount_sources | length
+    fail_msg: "Container mount sources and destinations must be unique. Failed with mounts: {{ container_mounts }}"
+    quiet: true