com.google.errorprone.bugpatterns.SystemConsoleNull Maven / Gradle / Ivy
/*
* Copyright 2024 The Error Prone 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 com.google.errorprone.bugpatterns;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.BinaryTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
import com.sun.tools.javac.code.Symbol;
import java.util.Objects;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
summary = "System.console() no longer returns null in JDK 22 and newer versions",
severity = WARNING)
public class SystemConsoleNull extends BugChecker
implements BugChecker.MethodInvocationTreeMatcher {
private static final Matcher MATCHER =
staticMethod().onClass("java.lang.System").named("console");
@Override
public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
if (!MATCHER.matches(tree, state)) {
return NO_MATCH;
}
Tree enclosing = state.getPath().getParentPath().getLeaf();
if (isNullCheck(enclosing)) {
return describeMatch(enclosing, buildFix(enclosing));
}
if (enclosing instanceof VariableTree
&& Objects.equals(((VariableTree) enclosing).getInitializer(), tree)) {
Symbol sym = ASTHelpers.getSymbol(enclosing);
if (ASTHelpers.isConsideredFinal(sym)) {
new SuppressibleTreePathScanner(state) {
@Override
public Void visitIdentifier(IdentifierTree tree, Void unused) {
if (sym.equals(ASTHelpers.getSymbol(tree))) {
Tree enclosing = getCurrentPath().getParentPath().getLeaf();
if (isNullCheck(enclosing)) {
state.reportMatch(describeMatch(tree, buildFix(enclosing, tree, state)));
}
}
return null;
}
}.scan(state.getPath().getCompilationUnit(), null);
}
}
return NO_MATCH;
}
private static SuggestedFix buildFix(Tree enclosing) {
return SuggestedFix.emptyFix();
}
private static SuggestedFix buildFix(
Tree enclosing, IdentifierTree identifier, VisitorState state) {
return SuggestedFix.emptyFix();
}
private static boolean isNullCheck(Tree tree) {
if (!(tree instanceof BinaryTree)) {
return false;
}
BinaryTree binaryTree = (BinaryTree) tree;
switch (binaryTree.getKind()) {
case EQUAL_TO:
case NOT_EQUAL_TO:
break;
default:
return false;
}
return binaryTree.getLeftOperand().getKind().equals(Tree.Kind.NULL_LITERAL)
|| binaryTree.getRightOperand().getKind().equals(Tree.Kind.NULL_LITERAL);
}
}