com.google.errorprone.bugpatterns.ComparableType Maven / Gradle / Ivy
/* Copyright 2017 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.
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package com.google.errorprone.bugpatterns;
import static com.google.common.collect.Iterables.getOnlyElement;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.getType;
import static com.google.errorprone.util.ASTHelpers.isSameType;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.Signatures;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.Tree;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Type.ClassType;
/** @author [email protected] (Ali Mesbah) */
@BugPattern(
name = "ComparableType",
summary =
"Implementing 'Comparable' where T is not the same as the implementing class is"
+ " incorrect, since it violates the symmetry contract of compareTo.",
severity = ERROR)
public class ComparableType extends BugChecker implements ClassTreeMatcher {
@Override
public Description matchClass(ClassTree tree, VisitorState state) {
Type comparableType = state.getSymtab().comparableType;
return tree.getImplementsClause().stream()
.filter(impl -> isSameType(getType(impl), comparableType, state))
.findAny()
.map(impl -> match(tree, impl, state))
.orElse(NO_MATCH);
}
Description match(ClassTree tree, Tree impl, VisitorState state) {
Type implType = getType(impl);
ClassType type = getType(tree);
if (implType.getTypeArguments().isEmpty()) {
return buildDescription(tree).setMessage("Comparable should not be raw").build();
}
Type comparableTypeArgument = getOnlyElement(implType.getTypeArguments());
if (!isSameType(type, comparableTypeArgument, state)) {
return buildDescription(tree)
.setMessage(
String.format(
"Type of Comparable (%s) is not the same as implementing class (%s).",
Signatures.prettyType(comparableTypeArgument), Signatures.prettyType(type)))
.build();
}
return NO_MATCH;
}
}