Validator.java

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// to you under the Apache License, Version 2.0 (the
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package org.apache.doris.nereids.processor.post;

import org.apache.doris.nereids.CascadesContext;
import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.trees.expressions.Slot;
import org.apache.doris.nereids.trees.expressions.SlotNotFromChildren;
import org.apache.doris.nereids.trees.expressions.literal.BooleanLiteral;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.algebra.Aggregate;
import org.apache.doris.nereids.trees.plans.physical.PhysicalFilter;
import org.apache.doris.nereids.trees.plans.physical.PhysicalProject;
import org.apache.doris.nereids.util.PlanUtils;
import org.apache.doris.nereids.util.Utils;

import com.google.common.base.Preconditions;

import java.util.List;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * validator plan.
 */
public class Validator extends PlanPostProcessor {

    @Override
    public Plan visitPhysicalProject(PhysicalProject<? extends Plan> project, CascadesContext context) {
        Preconditions.checkArgument(!project.getProjects().isEmpty(), "Project list can't be empty");
        return visit(project, context);
    }

    @Override
    public Plan visitPhysicalFilter(PhysicalFilter<? extends Plan> filter, CascadesContext context) {
        Preconditions.checkArgument(!filter.getConjuncts().isEmpty()
                && filter.getPredicate() != BooleanLiteral.TRUE, "Filter predicate can't be empty or true");

        return visit(filter, context);
    }

    @Override
    public Plan visit(Plan plan, CascadesContext context) {
        for (Plan child : plan.children()) {
            child.accept(this, context);
        }

        Optional<Slot> opt = checkAllSlotFromChildren(plan);
        if (opt.isPresent()) {
            List<Slot> childrenOutput = plan.children().stream().flatMap(p -> p.getOutput().stream()).collect(
                    Collectors.toList());
            throw new AnalysisException("A expression contains slot not from children\n"
                    + "Slot: " + opt.get() + "  Children Output:" + childrenOutput + "\n"
                    + "Plan: " + plan.treeString() + "\n");
        }
        return plan;
    }

    /**
     * Check all slot must from children.
     */
    public static Optional<Slot> checkAllSlotFromChildren(Plan plan) {
        if (plan.arity() == 0) {
            return Optional.empty();
        }
        // agg exist multi-phase
        if (plan instanceof Aggregate) {
            return Optional.empty();
        }
        Set<Slot> childOutputSet = Utils.fastToImmutableSet(PlanUtils.fastGetChildrenOutputs(plan.children()));
        Set<Slot> inputSlots = plan.getInputSlots();
        for (Slot slot : inputSlots) {
            if (slot.getName().startsWith("mv") || slot instanceof SlotNotFromChildren) {
                continue;
            }
            if (!(childOutputSet.contains(slot))) {
                return Optional.of(slot);
            }
        }
        return Optional.empty();
    }
}