| /* |
| * Copyright 2000-2013 JetBrains s.r.o. |
| * |
| * 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 com.jetbrains.python.inspections; |
| |
| import com.intellij.codeInspection.LocalInspectionToolSession; |
| import com.intellij.codeInspection.ProblemsHolder; |
| import com.intellij.psi.PsiElementVisitor; |
| import com.intellij.psi.ResolveResult; |
| import com.intellij.psi.util.PsiTreeUtil; |
| import com.jetbrains.python.PyBundle; |
| import com.jetbrains.python.inspections.quickfix.StatementEffectFunctionCallQuickFix; |
| import com.jetbrains.python.inspections.quickfix.StatementEffectIntroduceVariableQuickFix; |
| import com.jetbrains.python.psi.*; |
| import com.jetbrains.python.psi.types.PyType; |
| import org.jetbrains.annotations.Nls; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| /** |
| * @author Alexey.Ivanov |
| */ |
| public class PyStatementEffectInspection extends PyInspection { |
| @Nls |
| @NotNull |
| @Override |
| public String getDisplayName() { |
| return PyBundle.message("INSP.NAME.statement.effect"); |
| } |
| |
| @NotNull |
| @Override |
| public PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder, boolean isOnTheFly, @NotNull LocalInspectionToolSession session) { |
| return new Visitor(holder, session); |
| } |
| |
| @Override |
| protected boolean isSuppressForCodeFragment() { |
| return true; |
| } |
| |
| public static class Visitor extends PyInspectionVisitor { |
| |
| public Visitor(final ProblemsHolder holder, LocalInspectionToolSession session) { |
| super(holder, session); |
| } |
| |
| @Override |
| public void visitPyExpressionStatement(final PyExpressionStatement node) { |
| final PyExpression expression = node.getExpression(); |
| if (PsiTreeUtil.hasErrorElements(expression)) |
| return; |
| if (hasEffect(expression)) return; |
| |
| // https://twitter.com/gvanrossum/status/112670605505077248 |
| if (expression instanceof PyStringLiteralExpression) { |
| return; |
| } |
| |
| final PyTryPart tryPart = PsiTreeUtil.getParentOfType(node, PyTryPart.class); |
| if (tryPart != null) { |
| final PyStatementList statementList = tryPart.getStatementList(); |
| if (statementList.getStatements().length == 1 && statementList.getStatements()[0] == node) { |
| return; |
| } |
| } |
| if (expression instanceof PyReferenceExpression && !((PyReferenceExpression)expression).isQualified()) { |
| registerProblem(expression, PyBundle.message("INSP.NAME.statement.message")); |
| } |
| else { |
| registerProblem(expression, PyBundle.message("INSP.NAME.statement.message"), new StatementEffectIntroduceVariableQuickFix()); |
| } |
| } |
| |
| private boolean hasEffect(@Nullable PyExpression expression) { |
| if (expression == null) { |
| return false; |
| } |
| if (expression instanceof PyCallExpression || expression instanceof PyYieldExpression) { |
| return true; |
| } |
| else if (expression instanceof PyListCompExpression) { |
| if (hasEffect(((PyListCompExpression)expression).getResultExpression())) { |
| return true; |
| } |
| } |
| else if (expression instanceof PyBinaryExpression) { |
| PyBinaryExpression binary = (PyBinaryExpression)expression; |
| final PyExpression leftExpression = binary.getLeftExpression(); |
| final PyExpression rightExpression = binary.getRightExpression(); |
| if (hasEffect(leftExpression) || hasEffect(rightExpression)) return true; |
| |
| final PyElementType operator = binary.getOperator(); |
| String method = operator == null ? null : operator.getSpecialMethodName(); |
| if (method != null) { |
| // maybe the op is overridden and may produce side effects, like cout << "hello" |
| PyType type = myTypeEvalContext.getType(leftExpression); |
| if (type != null && |
| !type.isBuiltin() && |
| type.resolveMember(method, null, AccessDirection.READ, getResolveContext()) != null) { |
| return true; |
| } |
| if (rightExpression != null) { |
| type = myTypeEvalContext.getType(rightExpression); |
| if (type != null) { |
| String rmethod = "__r" + method.substring(2); // __add__ -> __radd__ |
| if (!type.isBuiltin() && type.resolveMember(rmethod, null, AccessDirection.READ, getResolveContext()) != null) { |
| return true; |
| } |
| } |
| } |
| } |
| } |
| else if (expression instanceof PyConditionalExpression) { |
| PyConditionalExpression conditionalExpression = (PyConditionalExpression)expression; |
| return hasEffect(conditionalExpression.getTruePart()) || hasEffect(conditionalExpression.getFalsePart()); |
| } |
| else if (expression instanceof PyParenthesizedExpression) { |
| PyParenthesizedExpression parenthesizedExpression = (PyParenthesizedExpression)expression; |
| return hasEffect(parenthesizedExpression.getContainedExpression()); |
| } |
| else if (expression instanceof PyReferenceExpression) { |
| PyReferenceExpression referenceExpression = (PyReferenceExpression)expression; |
| ResolveResult[] results = referenceExpression.getReference(getResolveContext()).multiResolve(true); |
| for (ResolveResult res : results) { |
| if (res.getElement() instanceof PyFunction) { |
| registerProblem(expression, "Statement seems to have no effect and can be replaced with function call to have effect", new StatementEffectFunctionCallQuickFix()); |
| return true; |
| } |
| } |
| } |
| else if (expression instanceof PyTupleExpression) { |
| PyExpression[] elements = ((PyTupleExpression)expression).getElements(); |
| for (PyExpression element : elements) { |
| if (hasEffect(element)) { |
| return true; |
| } |
| } |
| } |
| return false; |
| } |
| } |
| } |