Nested portlets unusable when configuration template is unavailable

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.2.X, 7.3.X, Master
• Fix Version/s: 7.2.10 DXP FP17, 7.2.10.6 DXP SP6, 7.2.X, 7.3.10.3 DXP SP3, 7.3.X, 7.4.3.5 CE GA5, 7.4.13 DXP U1, Master
• Component/s: Content Display Widgets > Nested Portlets widget
• Labels:
  • ee-ts
  • liferay-dxp-72-sp6
  • liferay-dxp-73-sp3
  • liferay-fix-pack-dxp-3-7310
  • liferay-fixpack-dxp-17-7210
  • liferay-fixpack-dxp-3-7310
  • liferay-update-dxp-1-7413
• Branch Version/s:
  7.3.x, 7.2.x
• Backported to Branch:
  Committed
• Fix Priority: 3
• Git Pull Request: https://github.com/liferay-echo/liferay-portal/pull/6233

Steps to reproduce:

1. Generate a new layout template and deploy the war to your server. You can follow this doc.
2. Add a Nested Applications portlet to a page. Configure it with the new template: three dots -> Configuration and select your template.
3. Remove the newly created layout template from your installation: you can delete it from the osgi/folder.
4. Configure the portlet with other available layout template (2 columns for example).

Expected result: 2 columns layout template is applied.

Current result: an error occurs and Nested Applications is temporarily unavailable.

Exception is:

2021-10-26 07:01:44.948 ERROR [http-nio-8080-exec-7][PortletServlet:119] javax.portlet.PortletException: java.lang.NullPointerException
javax.portlet.PortletException: java.lang.NullPointerException
 at com.liferay.portal.kernel.portlet.LiferayPortlet.callActionMethod(LiferayPortlet.java:209)
 at com.liferay.portal.kernel.portlet.bridges.mvc.MVCPortlet.callActionMethod(MVCPortlet.java:394)
{...}
Caused by: java.lang.NullPointerException
 at com.liferay.nested.portlets.web.internal.portlet.action.NestedPortletsConfigurationAction.reorganizeNestedColumns(NestedPortletsConfigurationAction.java:151)