org.codenarc.rule.groovyism.AssignCollectionUniqueRule.groovy Maven / Gradle / Ivy

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The CodeNarc project provides a static analysis tool for Groovy code.

There is a newer version: 3.5.0-groovy-4.0

/*
 * Copyright 2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.codenarc.rule.groovyism

import org.codehaus.groovy.ast.expr.DeclarationExpression
import org.codehaus.groovy.ast.expr.Expression
import org.codehaus.groovy.ast.expr.MethodCallExpression
import org.codehaus.groovy.ast.expr.VariableExpression
import org.codenarc.rule.AbstractAstVisitor
import org.codenarc.rule.AbstractAstVisitorRule
import org.codenarc.util.AstUtil

/**
 * the unique method mutates the original list. If a user is using the result of this method then they probably don't understand this
 *
 * @author Nick Larson
 * @author Juan Vazquez
 * @author Jon DeJong
 */
class AssignCollectionUniqueRule extends AbstractAstVisitorRule {
    String name = 'AssignCollectionUnique'
    int priority = 2
    Class astVisitorClass = AssignCollectionUniqueAstVisitor
}

class AssignCollectionUniqueAstVisitor extends AbstractAstVisitor {
    @Override
    void visitDeclarationExpression(DeclarationExpression expression) {
        Expression right = expression.rightExpression

        if (right instanceof MethodCallExpression) {
            if (isChainedUnique(right) || (isChainedUnique(right.objectExpression))) {
                addViolation(expression, 'unique() mutates the original list.')
            }
        }
        super.visitDeclarationExpression expression
    }

    private static boolean isChainedUnique(Expression right) {
        if (AstUtil.isMethodCall(right, 'unique', 0..1)) {
            if (right.objectExpression instanceof VariableExpression) {
                return true
            }
        }
        false
    }
}