CheckMatchExpression.java

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package org.apache.doris.nereids.rules.rewrite;

import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.rules.Rule;
import org.apache.doris.nereids.rules.RuleType;
import org.apache.doris.nereids.trees.expressions.Cast;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.Match;
import org.apache.doris.nereids.trees.expressions.SlotReference;
import org.apache.doris.nereids.trees.expressions.literal.Literal;
import org.apache.doris.nereids.trees.plans.Plan;
import org.apache.doris.nereids.trees.plans.logical.LogicalFilter;
import org.apache.doris.nereids.util.ExpressionUtils;

import java.util.List;

/**
 * Check match expression
 */
public class CheckMatchExpression extends OneRewriteRuleFactory {

    @Override
    public Rule build() {
        return logicalFilter(logicalOlapScan())
                .when(filter -> ExpressionUtils.containsTypes(filter.getExpressions(), Match.class))
                .then(this::checkChildren)
                .toRule(RuleType.CHECK_MATCH_EXPRESSION);
    }

    private Plan checkChildren(LogicalFilter<? extends Plan> filter) {
        List<Expression> expressions = filter.getExpressions();
        for (Expression expr : expressions) {
            if (expr instanceof Match) {
                Match matchExpression = (Match) expr;
                SlotReference slotReference = getSlotFromSlotOrCastChain(matchExpression.left());
                if (slotReference == null
                        || !(matchExpression.right() instanceof Literal)) {
                    throw new AnalysisException(String.format("Only support match left operand is SlotRef,"
                            + " right operand is Literal. But meet expression %s", matchExpression));
                }
                if (slotReference.getDataType().isVariantType() && !slotReference.hasSubColPath()) {
                    throw new AnalysisException(String.format("VARIANT root column does not support MATCH predicates. "
                                    + "Please query a subcolumn instead, for example %s['field'] MATCH 'xxx'",
                            slotReference.getName()));
                }
            }
        }
        return filter;
    }

    private SlotReference getSlotFromSlotOrCastChain(Expression expression) {
        Expression current = expression;
        while (current instanceof Cast) {
            current = current.child(0);
        }
        return current instanceof SlotReference ? (SlotReference) current : null;
    }
}