Upgrade to a Lucene 7 snapshot (#24089)

We want to upgrade to Lucene 7 ahead of time in order to be able to check whether it causes any trouble to Elasticsearch before Lucene 7.0 gets released. From a user perspective, the main benefit of this upgrade is the enhanced support for sparse fields, whose resource consumption is now function of the number of docs that have a value rather than the total number of docs in the index.

Some notes about the change:
 - it includes the deprecation of the `disable_coord` parameter of the `bool` and `common_terms` queries: Lucene has removed support for coord factors
 - it includes the deprecation of the `index.similarity.base` expert setting, since it was only useful to configure coords and query norms, which have both been removed
 - two tests have been marked with `@AwaitsFix` because of #23966, which we intend to address after the merge

1 files changed, 2 insertions, 2 deletions

diff --git a/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggester.java b/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggester.java
index abc8d209cd..0b127b2eee 100644
--- a/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggester.java
+++ b/core/src/main/java/org/elasticsearch/search/suggest/completion/CompletionSuggester.java
@@ -83,7 +83,7 @@ public class CompletionSuggester extends Suggester<CompletionSuggestionContext>
 
     private static void suggest(IndexSearcher searcher, CompletionQuery query, TopSuggestDocsCollector collector) throws IOException {
         query = (CompletionQuery) query.rewrite(searcher.getIndexReader());
-        Weight weight = query.createWeight(searcher, collector.needsScores());
+        Weight weight = query.createWeight(searcher, collector.needsScores(), 1f);
         for (LeafReaderContext context : searcher.getIndexReader().leaves()) {
             BulkScorer scorer = weight.bulkScorer(context);
             if (scorer != null) {
@@ -185,7 +185,7 @@ public class CompletionSuggester extends Suggester<CompletionSuggestionContext>
         private final Map<Integer, SuggestDoc> scoreDocMap;
 
         // TODO: expose dup removal
-        
+
         TopDocumentsCollector(int num) {
             super(1, false); // TODO hack, we don't use the underlying pq, so we allocate a size of 1
             this.num = num;