org.sonar.python.checks.NeedlessPassCheck Maven / Gradle / Ivy

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/*
 * SonarQube Python Plugin
 * Copyright (C) 2011-2020 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.python.checks;

import java.util.List;
import java.util.stream.Collectors;
import org.sonar.check.Rule;
import org.sonar.plugins.python.api.PythonSubscriptionCheck;
import org.sonar.plugins.python.api.tree.ExpressionStatement;
import org.sonar.plugins.python.api.tree.StatementList;
import org.sonar.plugins.python.api.tree.Statement;

import static org.sonar.plugins.python.api.tree.Tree.Kind.EXPRESSION_STMT;
import static org.sonar.plugins.python.api.tree.Tree.Kind.PASS_STMT;
import static org.sonar.plugins.python.api.tree.Tree.Kind.STATEMENT_LIST;
import static org.sonar.plugins.python.api.tree.Tree.Kind.STRING_LITERAL;

@Rule(key = "S2772")
public class NeedlessPassCheck extends PythonSubscriptionCheck {

  private static final String MESSAGE = "Remove this unneeded \"pass\".";

  @Override
  public void initialize(Context context) {
    context.registerSyntaxNodeConsumer(STATEMENT_LIST, ctx -> {
      List statements = ((StatementList) ctx.syntaxNode()).statements().stream()
        .filter(NeedlessPassCheck::isNotStringLiteralExpressionStatement)
        .collect(Collectors.toList());
      if (statements.size() <= 1) {
        return;
      }
      statements.stream()
        .filter(st -> st.is(PASS_STMT))
        .findFirst()
        .ifPresent(st -> ctx.addIssue(st, MESSAGE));
    });
  }

  private static boolean isNotStringLiteralExpressionStatement(Statement st) {
    return !(st.is(EXPRESSION_STMT) && ((ExpressionStatement) st).expressions().stream().allMatch(e -> e.is(STRING_LITERAL)));
  }
}