Solr queries with certain URL-encoded characters are decoded twice
The one character I know is a problem is + (%2B). When %2B is sent in a Solr query, Metacat seems to decode it twice - so that the second time it is decoded, it is interpreted as a space character, causing a Solr syntax error. The MetacatSolrIndex class decodes the query string after D1Httprequest has already decoded it.
Example query is: