Adding matchAllDocs support for vector fields

Author: Samiul-TheSoccerFan

x-pack/plugin/inference/src/main/java/org/elasticsearch/xpack/inference/highlight/SemanticTextHighlighter.java

@@ -15,6 +15,7 @@
 import org.apache.lucene.search.IndexSearcher;
 import org.apache.lucene.search.KnnByteVectorQuery;
 import org.apache.lucene.search.KnnFloatVectorQuery;
+import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.ScoreMode;
@@ -267,6 +268,8 @@ public void visitLeaf(Query query) {
                     queries.add(fieldType.createExactKnnQuery(VectorData.fromFloats(knnQuery.getTargetCopy()), null));
                 } else if (query instanceof KnnByteVectorQuery knnQuery) {
                     queries.add(fieldType.createExactKnnQuery(VectorData.fromBytes(knnQuery.getTargetCopy()), null));
+                } else if (query instanceof MatchAllDocsQuery) {
+                    queries.add(new MatchAllDocsQuery());
                 }
             }
         });
@@ -293,6 +296,13 @@ public QueryVisitor getSubVisitor(BooleanClause.Occur occur, Query parent) {
                 }
                 return this;
             }
+
+            @Override
+            public void visitLeaf(Query query) {
+                if (query instanceof MatchAllDocsQuery) {
+                    queries.add(new MatchAllDocsQuery());
+                }
+            }
         });
         return queries;
     }