com.google.errorprone.bugpatterns.MissingOverride Maven / Gradle / Ivy
/*
* Copyright 2015 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.WARNING;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.StandardTags;
import com.google.errorprone.ErrorProneFlags;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.MethodTree;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.MethodSymbol;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.Types;
import javax.annotation.Nullable;
import javax.lang.model.element.Modifier;
/** A {@link BugChecker}; see the associated {@link BugPattern} annotation for details. */
@BugPattern(
name = "MissingOverride",
summary = "method overrides method in supertype; expected @Override",
severity = WARNING,
tags = StandardTags.STYLE)
public class MissingOverride extends BugChecker implements MethodTreeMatcher {
/** if true, don't warn on missing {@code @Override} annotations inside interfaces */
private final boolean ignoreInterfaceOverrides;
public MissingOverride() {
this(ErrorProneFlags.empty());
}
public MissingOverride(ErrorProneFlags flags) {
this.ignoreInterfaceOverrides =
flags.getBoolean("MissingOverride:IgnoreInterfaceOverrides").orElse(false);
}
@Override
public Description matchMethod(MethodTree tree, VisitorState state) {
Symbol sym = ASTHelpers.getSymbol(tree);
if (sym.isStatic()) {
return Description.NO_MATCH;
}
if (ASTHelpers.hasAnnotation(sym, Override.class, state)) {
return Description.NO_MATCH;
}
MethodSymbol override = getFirstOverride(sym, state.getTypes());
if (override == null) {
return Description.NO_MATCH;
}
if (!ASTHelpers.getGeneratedBy(state).isEmpty()) {
return Description.NO_MATCH;
}
if (ASTHelpers.hasAnnotation(override, Deprecated.class, state)) {
// to allow deprecated methods to be removed non-atomically, we permit overrides of
// @Deprecated to skip the annotation
return Description.NO_MATCH;
}
return buildDescription(tree)
.addFix(SuggestedFix.prefixWith(tree, "@Override "))
.setMessage(
String.format(
"%s %s method in %s; expected @Override",
sym.getSimpleName(),
override.enclClass().isInterface()
|| override.getModifiers().contains(Modifier.ABSTRACT)
? "implements"
: "overrides",
override.enclClass().getSimpleName()))
.build();
}
/**
* Returns the {@link MethodSymbol} of the first method that sym overrides in its supertype
* closure, or {@code null} if no such method exists.
*/
@Nullable
private MethodSymbol getFirstOverride(Symbol sym, Types types) {
ClassSymbol owner = sym.enclClass();
if (ignoreInterfaceOverrides && owner.isInterface()) {
// pretend the method does not override anything
return null;
}
for (Type s : types.closure(owner.type)) {
if (types.isSameType(s, owner.type)) {
continue;
}
for (Symbol m : s.tsym.members().getSymbolsByName(sym.name)) {
if (!(m instanceof MethodSymbol)) {
continue;
}
MethodSymbol msym = (MethodSymbol) m;
if (msym.isStatic()) {
continue;
}
if (sym.overrides(msym, owner, types, /* checkResult= */ false)) {
return msym;
}
}
}
return null;
}
}