Reintroduce a light premapping layer

Author: bpintea

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/expression/function/fulltext/QueryBuilderResolver.java

@@ -26,7 +26,7 @@
 /**
  * Some {@link FullTextFunction} implementations such as {@link org.elasticsearch.xpack.esql.expression.function.fulltext.Match}
  * will be translated to a {@link QueryBuilder} that require a rewrite phase on the coordinator.
- * {@link QueryBuilderResolver#preprocess(LogicalPlan, TransportActionServices, ActionListener)} will rewrite the plan by
+ * {@link QueryBuilderResolver#resolveQueryBuilders(LogicalPlan, TransportActionServices, ActionListener)} will rewrite the plan by
  * replacing {@link FullTextFunction} expression with new ones that hold rewritten {@link QueryBuilder}s.
  */
 public final class QueryBuilderResolver {
@@ -35,7 +35,7 @@ public final class QueryBuilderResolver {
 
     private QueryBuilderResolver() {}
 
-    public void preprocess(LogicalPlan plan, TransportActionServices services, ActionListener<LogicalPlan> listener) {
+    public void resolveQueryBuilders(LogicalPlan plan, TransportActionServices services, ActionListener<LogicalPlan> listener) {
         var hasFullTextFunctions = plan.anyMatch(p -> {
             Holder<Boolean> hasFullTextFunction = new Holder<>(false);
             p.forEachExpression(FullTextFunction.class, unused -> hasFullTextFunction.set(true));

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

@@ -0,0 +1,37 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.esql.planner.premapper;
+
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.xpack.esql.expression.function.fulltext.QueryBuilderResolver;
+import org.elasticsearch.xpack.esql.plan.logical.LogicalPlan;
+import org.elasticsearch.xpack.esql.plugin.TransportActionServices;
+
+/**
+ * The class is responsible for invoking any premapping steps that need to be applied to the logical plan,
+ * before this is being mapped to a physical one.
+ */
+public class PreMapper {
+
+    private final TransportActionServices services;
+
+    public PreMapper(TransportActionServices services) {
+        this.services = services;
+    }
+
+    /**
+     * Invokes any premapping steps that need to be applied to the logical plan, before this is being mapped to a physical one.
+     */
+    public void preMapper(LogicalPlan plan, ActionListener<LogicalPlan> listener) {
+        queryRewrite(plan, listener);
+    }
+
+    private void queryRewrite(LogicalPlan plan, ActionListener<LogicalPlan> listener) {
+        QueryBuilderResolver.INSTANCE.resolveQueryBuilders(plan, services, listener);
+    }
+}

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/session/EsqlSession.java

@@ -48,7 +48,6 @@
 import org.elasticsearch.xpack.esql.enrich.ResolvedEnrichPolicy;
 import org.elasticsearch.xpack.esql.expression.UnresolvedNamePattern;
 import org.elasticsearch.xpack.esql.expression.function.EsqlFunctionRegistry;
-import org.elasticsearch.xpack.esql.expression.function.fulltext.QueryBuilderResolver;
 import org.elasticsearch.xpack.esql.index.EsIndex;
 import org.elasticsearch.xpack.esql.index.IndexResolution;
 import org.elasticsearch.xpack.esql.index.MappingException;
@@ -74,6 +73,7 @@
 import org.elasticsearch.xpack.esql.plan.physical.FragmentExec;
 import org.elasticsearch.xpack.esql.plan.physical.PhysicalPlan;
 import org.elasticsearch.xpack.esql.planner.mapper.Mapper;
+import org.elasticsearch.xpack.esql.planner.premapper.PreMapper;
 import org.elasticsearch.xpack.esql.plugin.TransportActionServices;
 import org.elasticsearch.xpack.esql.telemetry.PlanTelemetry;
 
@@ -111,12 +111,12 @@ public interface PlanRunner {
     private final Verifier verifier;
     private final EsqlFunctionRegistry functionRegistry;
     private final LogicalPlanOptimizer logicalPlanOptimizer;
+    private final PreMapper preMapper;
 
     private final Mapper mapper;
     private final PhysicalPlanOptimizer physicalPlanOptimizer;
     private final PlanTelemetry planTelemetry;
     private final IndicesExpressionGrouper indicesExpressionGrouper;
-    private final TransportActionServices services;
 
     public EsqlSession(
         String sessionId,
@@ -144,7 +144,7 @@ public EsqlSession(
         this.physicalPlanOptimizer = new PhysicalPlanOptimizer(new PhysicalOptimizerContext(configuration));
         this.planTelemetry = planTelemetry;
         this.indicesExpressionGrouper = indicesExpressionGrouper;
-        this.services = services;
+        this.preMapper = new PreMapper(services);
     }
 
     public String sessionId() {
@@ -164,25 +164,15 @@ public void execute(EsqlQueryRequest request, EsqlExecutionInfo executionInfo, P
             new EsqlSessionCCSUtils.CssPartialErrorsActionListener(executionInfo, listener) {
                 @Override
                 public void onResponse(LogicalPlan analyzedPlan) {
-                    preMapping(request, executionInfo, planRunner, optimizedPlan(analyzedPlan), listener);
+                    preMapper.preMapper(analyzedPlan, listener.delegateFailureAndWrap((l, p) -> {
+                        p.setOptimized(); // might have been updated by the preprocessor
+                        executeOptimizedPlan(request, executionInfo, planRunner, optimizedPlan(p), l);
+                    }));
                 }
             }
         );
     }
 
-    public void preMapping(
-        EsqlQueryRequest request,
-        EsqlExecutionInfo executionInfo,
-        PlanRunner planRunner,
-        LogicalPlan optimizedPlan,
-        ActionListener<Result> listener
-    ) {
-        QueryBuilderResolver.INSTANCE.preprocess(optimizedPlan, services, listener.delegateFailureAndWrap((l, p) -> {
-            p.setOptimized(); // might have been updated by the preprocessor
-            executeOptimizedPlan(request, executionInfo, planRunner, p, listener);
-        }));
-    }
-
     /**
      * Execute an analyzed plan. Most code should prefer calling {@link #execute} but
      * this is public for testing.