The official wildcards are % and _. But users can mistakenly use * and ? and those will usually work too. This works because the * and ? are valid wildcards in the underlying Lucene query language. But this breaks if the query is supposed to be run un-indexed for whatever reason.

To fix this we need to escape * and ? from user's input so they are no longer internally handled by Lucene as wildcards. These chars should cause an exact match instead. The actual recognized wildcards should be only % and _.