com.google.errorprone.bugpatterns.ThrowIfUncheckedKnownChecked Maven / Gradle / Ivy
/*
* Copyright 2016 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.ERROR;
import static com.google.errorprone.fixes.SuggestedFix.delete;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.matchers.Matchers.allOf;
import static com.google.errorprone.matchers.Matchers.anyOf;
import static com.google.errorprone.matchers.Matchers.argument;
import static com.google.errorprone.matchers.Matchers.argumentCount;
import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.tools.javac.code.Symtab;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Types;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.type.UnionType;
/** Catches no-op calls to {@code Throwables.throwIfUnchecked}. */
@BugPattern(summary = "throwIfUnchecked(knownCheckedException) is a no-op.", severity = ERROR)
public class ThrowIfUncheckedKnownChecked extends BugChecker
implements MethodInvocationTreeMatcher {
private static final Matcher IS_THROW_IF_UNCHECKED =
allOf(
anyOf(
staticMethod().onClass("com.google.common.base.Throwables").named("throwIfUnchecked"),
staticMethod()
.onClass("com.google.common.base.Throwables")
.named("propagateIfPossible")),
argumentCount(1));
private static final Matcher IS_KNOWN_CHECKED_EXCEPTION =
new Matcher() {
@Override
public boolean matches(ExpressionTree tree, VisitorState state) {
Type type = ASTHelpers.getType(tree);
if (type.isUnion()) {
for (TypeMirror alternative : ((UnionType) type).getAlternatives()) {
if (!isKnownCheckedException(state, (Type) alternative)) {
return false;
}
}
return true;
} else {
return isKnownCheckedException(state, type);
}
}
boolean isKnownCheckedException(VisitorState state, Type type) {
Types types = state.getTypes();
Symtab symtab = state.getSymtab();
// Check erasure for generics.
type = types.erasure(type);
return
// Has to be some Exception: A variable of type Throwable might be an Error.
types.isSubtype(type, symtab.exceptionType)
// Has to be some subtype: A variable of type Exception might be a RuntimeException.
&& !types.isSameType(type, symtab.exceptionType)
// Can't be of type RuntimeException.
&& !types.isSubtype(type, symtab.runtimeExceptionType);
}
};
@Override
public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
if (IS_THROW_IF_UNCHECKED.matches(tree, state)
&& argument(0, IS_KNOWN_CHECKED_EXCEPTION).matches(tree, state)) {
return describeMatch(tree, delete(state.getPath().getParentPath().getLeaf()));
}
return NO_MATCH;
}
}