[LUCENE-8492] UnifiedHighlighter does not work with Surround query parser (SurroundQParser)

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 7.2.1
• Fix Version/s: 8.2
• Component/s: modules/highlighter
• Lucene Fields: New
• Assignee: David Smiley
• Reporter: Andy Liu
• Created: 19/Apr/18 14:56
• Updated: 28/Aug/22 15:35
• Resolved: 21/Jun/19 21:20

Description

I'm attempting to use the UnifiedHighlighter in conjunction with queries parsed by Solr's SurroundQParserPlugin. When doing so, the response yields empty arrays for documents that should contain highlighted snippets.

I've attached a test for UnifiedHighlighter that uses the surround's QueryParser and preprocesses the query in a similar fashion as SurroundQParser, which results in test failure.  When creating a SpanQuery directly (rather via surround's QueryParser), the test passes.

The problem can be isolated to the code path initiated by UnifiedHighlighter.extractTerms(), which uses EMPTY_INDEXSEARCHER to extract terms from the query. After a series of method calls, we end up at DistanceQuery.getSpanNearQuery(), where ((DistanceSubQuery)sqi.next()).addSpanQueries(sncf) fails silently and doesn't add any span queries.  

Another data point: If I hack UnifiedHighlighter and pass in a live IndexSearcher to extractTerms(), highlighting works. 

Issue Links

• is related to: SOLR-12895 SurroundQParserPlugin support for UnifiedHighlighter
• is superceded by: LUCENE-8848 UnifiedHighlighter should highlight all Query types that implement Weight.matches