com.google.errorprone.bugpatterns.TryFailRefactoring Maven / Gradle / Ivy
/*
* Copyright 2018 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.common.collect.Iterables.getLast;
import static com.google.common.collect.Iterables.getOnlyElement;
import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
import static com.google.errorprone.BugPattern.StandardTags.REFACTORING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.matchers.Matchers.expressionStatement;
import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
import static com.sun.source.tree.Tree.Kind.UNION_TYPE;
import com.google.common.collect.Iterables;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.TryTreeMatcher;
import com.google.errorprone.fixes.Fix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.JUnitMatchers;
import com.google.errorprone.matchers.Matcher;
import com.sun.source.tree.CatchTree;
import com.sun.source.tree.ExpressionStatementTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.StatementTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.TryTree;
import java.util.List;
import java.util.Optional;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
name = "TryFailRefactoring",
summary = "Prefer assertThrows to try/fail",
severity = SUGGESTION,
tags = REFACTORING)
public class TryFailRefactoring extends BugChecker implements TryTreeMatcher {
private static final Matcher FAIL_METHOD =
expressionStatement(staticMethod().anyClass().named("fail"));
@Override
public Description matchTry(TryTree tree, VisitorState state) {
MethodTree enclosingMethod = state.findEnclosing(MethodTree.class);
if (enclosingMethod == null || !JUnitMatchers.TEST_CASE.matches(enclosingMethod, state)) {
return NO_MATCH;
}
List body = tree.getBlock().getStatements();
if (body.isEmpty() || tree.getFinallyBlock() != null || tree.getCatches().size() != 1) {
// TODO(cushon): support finally
// TODO(cushon): support multiple catch blocks
return NO_MATCH;
}
CatchTree catchTree = getOnlyElement(tree.getCatches());
if (catchTree.getParameter().getType().getKind() == UNION_TYPE) {
// TODO(cushon): handle multi-catch
return NO_MATCH;
}
if (!FAIL_METHOD.matches(getLast(body), state)) {
return NO_MATCH;
}
// try body statements, excluding the trailing `fail()`
List throwingStatements = body.subList(0, body.size() - 1);
Iterable failArgs =
((MethodInvocationTree) ((ExpressionStatementTree) getLast(body)).getExpression())
.getArguments();
Optional message = Optional.ofNullable(Iterables.get(failArgs, 0, null));
Optional fix =
AssertThrowsUtils.tryFailToAssertThrows(tree, throwingStatements, message, state);
return fix.map(f -> describeMatch(tree, f)).orElse(NO_MATCH);
}
}