com.google.errorprone.bugpatterns.UnnecessarilyFullyQualified Maven / Gradle / Ivy
/*
* Copyright 2020 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.getOnlyElement;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.util.ASTHelpers.getGeneratedBy;
import static com.google.errorprone.util.ASTHelpers.getSymbol;
import static com.google.errorprone.util.FindIdentifiers.findIdent;
import static com.sun.tools.javac.code.Kinds.KindSelector.VAL_TYP;
import com.google.common.base.Ascii;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Table;
import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.SeverityLevel;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.CompilationUnitTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.ImportTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.SimpleTreeVisitor;
import com.sun.source.util.TreePath;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
import com.sun.tools.javac.code.Symbol.PackageSymbol;
import com.sun.tools.javac.code.Symbol.TypeSymbol;
import com.sun.tools.javac.util.Position;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import javax.lang.model.element.Name;
/** Flags uses of fully qualified names which are not ambiguous if imported. */
@BugPattern(
name = "UnnecessarilyFullyQualified",
severity = SeverityLevel.WARNING,
summary = "This fully qualified name is unambiguous to the compiler if imported.")
public final class UnnecessarilyFullyQualified extends BugChecker
implements CompilationUnitTreeMatcher {
private static final ImmutableSet EXEMPTED_NAMES = ImmutableSet.of("Annotation");
@Override
public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState state) {
if (tree.getTypeDecls().stream()
.anyMatch(
t -> getSymbol(tree) != null && !getGeneratedBy(getSymbol(tree), state).isEmpty())) {
return NO_MATCH;
}
if (isPackageInfo(tree)) {
return NO_MATCH;
}
Table> table = HashBasedTable.create();
Set identifiersSeen = new HashSet<>();
new SuppressibleTreePathScanner() {
@Override
public Void visitImport(ImportTree importTree, Void unused) {
return null;
}
@Override
public Void visitMemberSelect(MemberSelectTree memberSelectTree, Void unused) {
if (!shouldIgnore()) {
handle(getCurrentPath());
}
return super.visitMemberSelect(memberSelectTree, null);
}
@Override
public Void visitIdentifier(IdentifierTree identifierTree, Void unused) {
identifiersSeen.add(identifierTree.getName());
return null;
}
private boolean shouldIgnore() {
// Don't report duplicate hits if we're not at the tail of a series of member selects on
// classes.
Tree parentTree = getCurrentPath().getParentPath().getLeaf();
return parentTree instanceof MemberSelectTree
&& getSymbol(parentTree) instanceof ClassSymbol;
}
private void handle(TreePath path) {
MemberSelectTree tree = (MemberSelectTree) path.getLeaf();
if (!isFullyQualified(tree)) {
return;
}
if (BadImport.BAD_NESTED_CLASSES.contains(tree.getIdentifier().toString())) {
if (tree.getExpression() instanceof MemberSelectTree
&& getSymbol(tree.getExpression()) instanceof ClassSymbol) {
handle(new TreePath(path, tree.getExpression()));
}
return;
}
Symbol symbol = getSymbol(tree);
if (!(symbol instanceof ClassSymbol)) {
return;
}
if (state.getEndPosition(tree) == Position.NOPOS) {
return;
}
List treePaths = table.get(tree.getIdentifier(), symbol.type.tsym);
if (treePaths == null) {
treePaths = new ArrayList<>();
table.put(tree.getIdentifier(), symbol.type.tsym, treePaths);
}
treePaths.add(path);
}
private boolean isFullyQualified(MemberSelectTree tree) {
AtomicBoolean isFullyQualified = new AtomicBoolean();
new SimpleTreeVisitor() {
@Override
public Void visitMemberSelect(MemberSelectTree memberSelectTree, Void unused) {
return visit(memberSelectTree.getExpression(), null);
}
@Override
public Void visitIdentifier(IdentifierTree identifierTree, Void aVoid) {
if (getSymbol(identifierTree) instanceof PackageSymbol) {
isFullyQualified.set(true);
}
return null;
}
}.visit(tree, null);
return isFullyQualified.get();
}
}.scan(state.getPath(), null);
for (Map.Entry>> rows : table.rowMap().entrySet()) {
Name name = rows.getKey();
Map> types = rows.getValue();
// Skip places where the same simple name refers to multiple types.
if (types.size() > 1) {
continue;
}
// Skip weird Android classes which don't look like classes.
if (Ascii.isLowerCase(name.charAt(0))) {
continue;
}
if (identifiersSeen.contains(name)) {
continue;
}
String nameString = name.toString();
if (EXEMPTED_NAMES.contains(nameString)) {
continue;
}
List pathsToFix = getOnlyElement(types.values());
if (pathsToFix.stream()
.anyMatch(path -> findIdent(nameString, state.withPath(path), VAL_TYP) != null)) {
continue;
}
SuggestedFix.Builder fixBuilder = SuggestedFix.builder();
fixBuilder.addImport(getOnlyElement(types.keySet()).getQualifiedName().toString());
for (TreePath path : pathsToFix) {
fixBuilder.replace(path.getLeaf(), nameString);
}
SuggestedFix fix = fixBuilder.build();
for (TreePath path : pathsToFix) {
state.reportMatch(describeMatch(path.getLeaf(), fix));
}
}
return NO_MATCH;
}
private static boolean isPackageInfo(CompilationUnitTree tree) {
String name = ASTHelpers.getFileName(tree);
int idx = name.lastIndexOf('/');
if (idx != -1) {
name = name.substring(idx + 1);
}
return name.equals("package-info.java");
}
}