NPE when setting Type facet frequency threshold to 0

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 7.1.X, Master
• Fix Version/s: 7.2.X, 7.3.10 DXP GA1
• Component/s: Web Search > Search Widgets
• Labels:
  • 7.2-should
  • QA-V
  • SMEQAFP3
  • ee-ts
  • sme-must-7.2
• Branch Version/s:
  7.2.x
• Backported to Branch:
  Committed
• Story Points: 1
• Fix Priority: 4
• Sprint: Search | S02 Sprint 20, Search | S03 Sprint 1, Search|S03 Sprint 13| 3.16-4.6
• Git Pull Request: https://github.com/thektan/liferay-portal/pull/172

Steps to reproduce:

1. Add Type Facet to page
2. Configure Type Facet:
   • Frequency Threshold: 0
3. Save

Result: Facet portlet is unavailable and NPE is thrown

2018-06-14 16:26:26.015 ERROR [http-nio-9080-exec-4][render_portlet_jsp:131] null
java.lang.NullPointerException
	at com.liferay.portal.search.web.internal.facet.display.builder.AssetEntriesSearchFacetDisplayBuilder.buildTermDisplayContexts(AssetEntriesSearchFacetDisplayBuilder.java:125)
	at com.liferay.portal.search.web.internal.facet.display.builder.AssetEntriesSearchFacetDisplayBuilder.build(AssetEntriesSearchFacetDisplayBuilder.java:45)
	at com.liferay.portal.search.web.internal.type.facet.portlet.TypeFacetPortlet.buildDisplayContext(TypeFacetPortlet.java:138)
	at com.liferay.portal.search.web.internal.type.facet.portlet.TypeFacetPortlet.render(TypeFacetPortlet.java:81)
	at com.liferay.portlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:127)
	at com.liferay.portlet.ScriptDataPortletFilter.doFilter(ScriptDataPortletFilter.java:58)
	at com.liferay.portlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:124)
	at com.liferay.portal.kernel.portlet.PortletFilterUtil.doFilter(PortletFilterUtil.java:71)
	at com.liferay.portal.kernel.servlet.PortletServlet.service(PortletServlet.java:108)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
	at org.eclipse.equinox.http.servlet.internal.registration.EndpointRegistration.service(EndpointRegistration.java:153)
	at org.eclipse.equinox.http.servlet.internal.servlet.ResponseStateHandler.processRequest(ResponseStateHandler.java:62)
	at org.eclipse.equinox.http.servlet.internal.context.DispatchTargets.doDispatch(DispatchTargets.java:118)
	at org.eclipse.equinox.http.servlet.internal.servlet.RequestDispatcherAdaptor.include(RequestDispatcherAdaptor.java:48)
	at com.liferay.portlet.internal.InvokerPortletImpl.invoke(InvokerPortletImpl.java:606)
	at com.liferay.portlet.internal.InvokerPortletImpl.invokeRender(InvokerPortletImpl.java:702)
	at com.liferay.portlet.internal.InvokerPortletImpl.render(InvokerPortletImpl.java:399)
	at com.liferay.portal.monitoring.internal.portlet.MonitoringInvokerPortlet.lambda$render$0(MonitoringInvokerPortlet.java:272)
	at com.liferay.portal.monitoring.internal.portlet.MonitoringInvokerPortlet._render(MonitoringInvokerPortlet.java:375)
	at com.liferay.portal.monitoring.internal.portlet.MonitoringInvokerPortlet.render(MonitoringInvokerPortlet.java:270)

Reproduced on:
Tomcat 9.0.6 + MySQL 5.7.22
Portal Master Git SHA: c9735ba64e66d4db7148496b89815f8dc059a6c1