Do not use EmptyAttribute

Author: przemekwitek

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/optimizer/LogicalVerifier.java

@@ -39,7 +39,7 @@ public Failures verify(LogicalPlan plan) {
         });
 
         if (dependencyFailures.hasFailures()) {
-//            throw new IllegalStateException(dependencyFailures.toString());
+            throw new IllegalStateException(dependencyFailures.toString());
         }
 
         return failures;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/optimizer/PhysicalVerifier.java

@@ -66,7 +66,7 @@ public Failures verify(PhysicalPlan plan) {
         });
 
         if (depFailures.hasFailures()) {
-//            throw new IllegalStateException(depFailures.toString());
+            throw new IllegalStateException(depFailures.toString());
         }
 
         return failures;

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/LogicalPlanBuilder.java

@@ -479,7 +479,7 @@ public PlanFactory visitChangePointCommand(EsqlBaseParser.ChangePointCommandCont
         Source src = source(ctx);
         Attribute value = visitQualifiedName(ctx.value);
         Attribute key = ctx.key == null ? new UnresolvedAttribute(src, "@timestamp") : visitQualifiedName(ctx.key);
-        Attribute partitionField = ctx.partitionField == null ? new EmptyAttribute(src) : visitQualifiedName(ctx.partitionField);
+        Attribute partitionField = visitQualifiedName(ctx.partitionField);
         Attribute targetType = new ReferenceAttribute(
             src,
             ctx.targetType == null ? "type" : visitQualifiedName(ctx.targetType).name(),

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

@@ -821,7 +821,7 @@ private PhysicalOperation planChangePoint(ChangePointExec changePoint, LocalExec
         return source.with(
             new ChangePointOperator.Factory(
                 layout.get(changePoint.value().id()).channel(),
-                changePoint.partitionField() instanceof EmptyAttribute == false ? Optional.of(layout.get(changePoint.partitionField().id()).channel()) : Optional.empty(),
+                changePoint.partitionField() != null ? Optional.of(layout.get(changePoint.partitionField().id()).channel()) : Optional.empty(),
                 changePoint.sourceText(),
                 changePoint.sourceLocation().getLineNumber(),
                 changePoint.sourceLocation().getColumnNumber()