No space specified on URL search produces Illegal Argument exception

Cause:
java.lang.IllegalArgumentException: Null space key in spaces list
 at com.atlassian.confluence.search.v2.query.InSpaceQuery.(InSpaceQuery.java:39)

Stack Trace: [hide]

java.lang.IllegalArgumentException: Null space key in spaces list
	at com.atlassian.confluence.search.v2.query.InSpaceQuery.(InSpaceQuery.java:39)
	at com.atlassian.confluence.search.v2.DefaultPredefinedQueryBuilder.siteSearchQuery(DefaultPredefinedQueryBuilder.java:40)
	at com.atlassian.confluence.search.actions.SearchSiteAction.execute(SearchSiteAction.java:139)
	at com.opensymphony.xwork.DefaultActionInvocation.invoke(DefaultActionInvocation.java:168)
	at com.opensymphony.xwork.interceptor.AroundInterceptor.intercept(AroundInterceptor.java:35)