Pure disjunctions should rewrite to a MatchNoneQueryBuilder (#48557) (#49673)

Closes #48475

Author: jpountz

server/src/main/java/org/elasticsearch/index/query/BoolQueryBuilder.java

@@ -424,12 +424,19 @@ protected QueryBuilder doRewrite(QueryRewriteContext queryRewriteContext) throws
         changed |= rewriteClauses(queryRewriteContext, mustNotClauses, newBuilder::mustNot);
         changed |= rewriteClauses(queryRewriteContext, filterClauses, newBuilder::filter);
         changed |= rewriteClauses(queryRewriteContext, shouldClauses, newBuilder::should);
+        // early termination when must clause is empty and optional clauses is returning MatchNoneQueryBuilder
+        if(mustClauses.size() == 0 && filterClauses.size() == 0 && shouldClauses.size() > 0
+            && newBuilder.shouldClauses.stream().allMatch(b -> b instanceof MatchNoneQueryBuilder)) {
+                return new MatchNoneQueryBuilder();
+        }
+
         // lets do some early termination and prevent any kind of rewriting if we have a mandatory query that is a MatchNoneQueryBuilder
         Optional<QueryBuilder> any = Stream.concat(newBuilder.mustClauses.stream(), newBuilder.filterClauses.stream())
             .filter(b -> b instanceof MatchNoneQueryBuilder).findAny();
         if (any.isPresent()) {
             return any.get();
         }
+
         if (changed) {
             newBuilder.adjustPureNegative = adjustPureNegative;
             newBuilder.minimumShouldMatch = minimumShouldMatch;

server/src/test/java/org/elasticsearch/index/query/BoolQueryBuilderTests.java

@@ -371,5 +371,20 @@ public void testRewriteWithMatchNone() throws IOException {
             .filter(new MatchNoneQueryBuilder()));
         rewritten = Rewriteable.rewrite(boolQueryBuilder, createShardContext());
         assertEquals(new MatchNoneQueryBuilder(), rewritten);
+
+        boolQueryBuilder = new BoolQueryBuilder();
+        boolQueryBuilder.should(new WrapperQueryBuilder(new MatchNoneQueryBuilder().toString()));
+        rewritten = Rewriteable.rewrite(boolQueryBuilder, createShardContext());
+        assertEquals(new MatchNoneQueryBuilder(), rewritten);
+
+        boolQueryBuilder = new BoolQueryBuilder();
+        boolQueryBuilder.should(new TermQueryBuilder("foo", "bar"));
+        boolQueryBuilder.should(new WrapperQueryBuilder(new MatchNoneQueryBuilder().toString()));
+        rewritten = Rewriteable.rewrite(boolQueryBuilder, createShardContext());
+        assertNotEquals(new MatchNoneQueryBuilder(), rewritten);
+
+        boolQueryBuilder = new BoolQueryBuilder();
+        rewritten = Rewriteable.rewrite(boolQueryBuilder, createShardContext());
+        assertNotEquals(new MatchNoneQueryBuilder(), rewritten);
     }
 }