solr 5.5: swap + unload does not work

[Fabrizio Fortino <ff...@gilt.com>]

I have created a Solr CoreAdminHandler extension with the goal to swap two
cores and remove the old one.

My code looks like this:

SolrCore core = coreContainer.create("newcore", coreProps)
coreContainer.swap("newcore", "livecore")
// the old livecore is now newcore, so unload it and remove all the related
dirs
coreContainer.unload("newcore", true, true, true)

After the last statement get executed the Solr log starts printing the
following messages forever

61424 INFO (pool-1-thread-1) [ x:newcore] o.a.s.c.SolrCore Core newcore is
not yet closed, waiting 100 ms before checking again.

I tried to call the close() method on the SolrCore instance before and
after the unload but the result is the same.


I opened an issue on the problem
(https://issues.apache.org/jira/browse/SOLR-8757) but the jira has not
been
acknowledged yet.

I'd like to know if my code is wrong or is a Solr bug. In case of a bug it
would be nice to have a workaround.

Thanks