Wrap non-scoring functions so we always get a DoubleVector

Author: carlosdelest

x-pack/plugin/esql/src/internalClusterTest/java/org/elasticsearch/xpack/esql/plugin/MatchFunctionIT.java

@@ -342,6 +342,27 @@ public void testDisjunctionScoringWithNot() {
         }
     }
 
+    public void testScoringWithNoFullTextFunction() {
+        var query = """
+            FROM test METADATA _score
+            | WHERE length(content) > 50
+            | KEEP id, _score
+            | SORT _score DESC, id ASC
+            """;
+
+        try (var resp = run(query)) {
+            assertColumnNames(resp.columns(), List.of("id", "_score"));
+            assertColumnTypes(resp.columns(), List.of("integer", "double"));
+            List<List<Object>> values = getValuesList(resp);
+            assertThat(values.size(), equalTo(1));
+
+            assertThat(values.get(0).get(0), equalTo(4));
+
+            // Non pushable query gets score of 0.0
+            assertThat((Double) values.get(0).get(1), equalTo(0.0));
+        }
+    }
+
     private void createAndPopulateIndex() {
         var indexName = "test";
         var client = client().admin().indices();

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/planner/LocalExecutionPlanner.java

@@ -70,6 +70,7 @@
 import org.elasticsearch.xpack.esql.enrich.LookupFromIndexService;
 import org.elasticsearch.xpack.esql.evaluator.EvalMapper;
 import org.elasticsearch.xpack.esql.evaluator.command.GrokEvaluatorExtracter;
+import org.elasticsearch.xpack.esql.evaluator.mapper.BooleanToScoringExpressionEvaluator;
 import org.elasticsearch.xpack.esql.expression.Order;
 import org.elasticsearch.xpack.esql.plan.physical.AggregateExec;
 import org.elasticsearch.xpack.esql.plan.physical.DissectExec;
@@ -686,7 +687,9 @@ private PhysicalOperation planFilter(FilterExec filter, LocalExecutionPlannerCon
             shardContexts,
             usesScore
         );
-
+        if (usesScore) {
+            evaluatorFactory = new BooleanToScoringExpressionEvaluator.Factory(evaluatorFactory);
+        }
         return source.with(new FilterOperatorFactory(evaluatorFactory, PlannerUtils.usesScoring(filter)), source.layout);
     }