Using WildcardQuery with MultiSearcher, and Boolean MUST_NOT clause

• Key: LUCENE-538
• Type: Bug
• Status: Open
• Priority: Minor
• Assignee: Unassigned
• Reporter: Helen Warren
• Component/s: Search
• Affects Version/s: 1.9

Description

We are searching across multiple indices using a MultiSearcher. There seems to be a problem when we use a WildcardQuery to exclude documents from the result set. I attach a set of unit tests illustrating the problem.

In these tests, we have two indices. Each index contains a set of documents with fields for 'title', 'section' and 'index'. The final aim is to do a keyword search, across both indices, on the title field and be able to exclude documents from certain sections (and their subsections) using a
WildcardQuery on the section field.

e.g. return documents from both indices which have the string 'xyzpqr' in their title but which do not lie
in the news section or its subsections (section = /news/*).

The first unit test (testExcludeSectionsWildCard) fails trying to do this.
If we relax any of the constraints made above, tests pass:

• Don't use WildcardQuery, but pass in the news section and it's child section to exclude explicitly (testExcludeSectionsExplicit)</li>
• Exclude results from just one section, not it's children too i.e. don't use WildcardQuery(testExcludeSingleSection)</li>
• Do use WildcardQuery, and exclude a section and its children, but just use one index thereby using the simple
  IndexReader and IndexSearcher objects (testExcludeSectionsOneIndex).
• Try the boolean MUST clause rather than MUST_NOT using the WildcardQuery i.e. only include results from the /news/ section
  and its children.