/*
* Copyright 2011 Google Inc. All Rights Reserved.
*
* 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.Category.JDK;
import static com.google.errorprone.BugPattern.MaturityLevel.MATURE;
import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
import static com.google.errorprone.matchers.Matchers.allOf;
import static com.google.errorprone.matchers.Matchers.anyOf;
import static com.google.errorprone.matchers.Matchers.enclosingClass;
import static com.google.errorprone.matchers.Matchers.enclosingMethod;
import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
import static com.google.errorprone.matchers.Matchers.kindIs;
import static com.google.errorprone.matchers.Matchers.lastStatement;
import static com.google.errorprone.matchers.Matchers.not;
import static com.google.errorprone.matchers.Matchers.parentNode;
import static com.google.errorprone.suppliers.Suppliers.EXCEPTION_TYPE;
import static com.sun.source.tree.Tree.Kind.EXPRESSION_STATEMENT;
import static com.sun.source.tree.Tree.Kind.IF;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.NewClassTreeMatcher;
import com.google.errorprone.fixes.Fix;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Enclosing;
import com.google.errorprone.matchers.JUnitMatchers;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.sun.source.tree.NewClassTree;
import com.sun.source.tree.StatementTree;
import com.sun.source.tree.Tree;
/**
* @author alexeagle@google.com (Alex Eagle)
*/
@BugPattern(name = "DeadException", altNames = "ThrowableInstanceNeverThrown",
summary = "Exception created but not thrown",
explanation =
"The exception is created with new, but is not thrown, and the reference is lost.",
category = JDK, severity = ERROR, maturity = MATURE)
public class DeadException extends BugChecker implements NewClassTreeMatcher {
public static final Matcher<Tree> MATCHER = allOf(
parentNode(kindIs(EXPRESSION_STATEMENT)),
isSubtypeOf(EXCEPTION_TYPE),
not(enclosingMethod(JUnitMatchers.wouldRunInJUnit4)),
anyOf(not(enclosingMethod(JUnitMatchers.isJunit3TestCase)),
not(enclosingClass(JUnitMatchers.isJUnit3TestClass)))
);
@Override
public Description matchNewClass(NewClassTree newClassTree, VisitorState state) {
if (!MATCHER.matches(newClassTree, state)) {
return Description.NO_MATCH;
}
StatementTree parent = (StatementTree) state.getPath().getParentPath().getLeaf();
boolean isLastStatement = anyOf(
new Enclosing.BlockOrCase<>(lastStatement(Matchers.<StatementTree>isSame(parent))),
// it could also be a bare if statement with no braces
parentNode(parentNode(kindIs(IF))))
.matches(newClassTree, state);
Fix fix;
if (isLastStatement) {
fix = SuggestedFix.prefixWith(newClassTree, "throw ");
} else {
fix = SuggestedFix.delete(parent);
}
return describeMatch(newClassTree, fix);
}
}