com.google.errorprone.bugpatterns.IncorrectMainMethod Maven / Gradle / Ivy
/*
* Copyright 2022 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.common.collect.Sets.immutableEnumSet;
import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.getSymbol;
import static com.google.errorprone.util.ASTHelpers.getType;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.BugPattern;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.fixes.SuggestedFixes;
import com.google.errorprone.matchers.Description;
import com.sun.source.tree.MethodTree;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
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.element.Modifier;
/** Bugpattern for incorrect overloads of main. */
@BugPattern(summary = "'main' methods must be public, static, and void", severity = WARNING)
public final class IncorrectMainMethod extends BugChecker implements MethodTreeMatcher {
private static final ImmutableSet REQUIRED_MODIFIERS =
immutableEnumSet(Modifier.PUBLIC, Modifier.STATIC);
@Override
public Description matchMethod(MethodTree tree, VisitorState state) {
if (!tree.getName().contentEquals("main")) {
return NO_MATCH;
}
MethodSymbol sym = getSymbol(tree);
if (sym.getParameters().size() != 1) {
return NO_MATCH;
}
Type type = getOnlyElement(sym.getParameters()).asType();
Types types = state.getTypes();
Symtab symtab = state.getSymtab();
if (!types.isArray(type) || !types.isSameType(types.elemtype(type), symtab.stringType)) {
return NO_MATCH;
}
if (sym.getModifiers().containsAll(REQUIRED_MODIFIERS)
&& types.isSameType(getType(tree.getReturnType()), symtab.voidType)) {
return NO_MATCH;
}
SuggestedFix.Builder fix = SuggestedFix.builder().replace(tree.getReturnType(), "void");
SuggestedFixes.removeModifiers(tree, state, Modifier.PROTECTED, Modifier.PRIVATE)
.ifPresent(fix::merge);
SuggestedFixes.addModifiers(tree, tree.getModifiers(), state, REQUIRED_MODIFIERS)
.ifPresent(fix::merge);
return describeMatch(tree, fix.build());
}
}