Skip to content

Commit

Permalink
Suggest AutoValue classes to mark manually written equals, hashCode a…
Browse files Browse the repository at this point in the history 
…nd toString to be final

RELNOTES: Suggest AutoValue classes to mark manually written equals, hashCode and toString to be final

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=204033438
  • Loading branch information
@sumitbhagwani @ronshapiro
sumitbhagwani authored and ronshapiro committed Jul 13, 2018
1 parent e8116bc commit a5cb666
Show file tree
Hide file tree
Showing 4 changed files with 240 additions and 0 deletions.
106 changes: 106 additions & 0 deletions core/src/main/java/com/google/errorprone/bugpatterns/AutoValueFinalMethods.java
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,106 @@
/*
* 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.errorprone.BugPattern.SeverityLevel.WARNING;
import static com.google.errorprone.matchers.Description.NO_MATCH;
import static com.google.errorprone.matchers.Matchers.allOf;
import static com.google.errorprone.matchers.Matchers.anyOf;
import static com.google.errorprone.matchers.Matchers.isSameType;
import static com.google.errorprone.matchers.Matchers.methodHasParameters;
import static com.google.errorprone.matchers.Matchers.methodIsNamed;
import static com.google.errorprone.matchers.Matchers.methodReturns;
import static com.google.errorprone.matchers.Matchers.not;
import static com.google.errorprone.matchers.Matchers.variableType;
import static com.google.errorprone.suppliers.Suppliers.BOOLEAN_TYPE;
import static com.google.errorprone.suppliers.Suppliers.INT_TYPE;
import static com.google.errorprone.suppliers.Suppliers.STRING_TYPE;

import com.google.errorprone.BugPattern;
import com.google.errorprone.BugPattern.ProvidesFix;
import com.google.errorprone.VisitorState;
import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
import com.google.errorprone.fixes.SuggestedFix;
import com.google.errorprone.fixes.SuggestedFixes;
import com.google.errorprone.matchers.Description;
import com.google.errorprone.matchers.Matcher;
import com.google.errorprone.matchers.Matchers;
import com.google.errorprone.util.ASTHelpers;
import com.sun.source.tree.ClassTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.Tree;
import java.util.Optional;
import javax.lang.model.element.Modifier;

/**
* Checks the toString(), hashCode() and equals() methods are final in AutoValue classes.
*
* @author bhagwani@google.com (Sumit Bhagwani)
*/
@BugPattern(
name = "AutoValueFinalMethods",
summary =
"Make toString(), hashCode() and equals() final in AutoValue classes"
+ ", so it is clear to readers that AutoValue is not overriding them",
severity = WARNING,
providesFix = ProvidesFix.REQUIRES_HUMAN_ATTENTION)
public class AutoValueFinalMethods extends BugChecker implements ClassTreeMatcher {

private static final Matcher<MethodTree> EQUALS_MATCHER =
allOf(
methodIsNamed("equals"),
methodHasParameters(variableType(isSameType("java.lang.Object"))),
methodReturns(BOOLEAN_TYPE));

private static final Matcher<MethodTree> TO_STRING_MATCHER =
allOf(methodIsNamed("toString"), methodHasParameters(), methodReturns(STRING_TYPE));

private static final Matcher<MethodTree> HASH_CODE_MATCHER =
allOf(methodIsNamed("hashCode"), methodHasParameters(), methodReturns(INT_TYPE));

// public non-final eq/ts/hs methods
private static final Matcher<MethodTree> METHOD_MATCHER =
allOf(
Matchers.<MethodTree>hasModifier(Modifier.PUBLIC),
not(Matchers.<MethodTree>hasModifier(Modifier.ABSTRACT)),
not(Matchers.<MethodTree>hasModifier(Modifier.FINAL)),
anyOf(EQUALS_MATCHER, TO_STRING_MATCHER, HASH_CODE_MATCHER));

@Override
public Description matchClass(ClassTree tree, VisitorState state) {
if (!ASTHelpers.hasAnnotation(tree, "com.google.auto.value.AutoValue", state)) {
return NO_MATCH;
}
SuggestedFix.Builder fix = SuggestedFix.builder();
for (Tree memberTree : tree.getMembers()) {
if (!(memberTree instanceof MethodTree)) {
continue;
}
if (METHOD_MATCHER.matches((MethodTree) memberTree, state)) {
Optional<SuggestedFix> optionalSuggestedFix =
SuggestedFixes.addModifiers(memberTree, state, Modifier.FINAL);
if (optionalSuggestedFix.isPresent()) {
fix.merge(optionalSuggestedFix.get());
}
}
}
if (!fix.isEmpty()) {
return describeMatch(tree, fix.build());
}
return NO_MATCH;
}
}
2 changes: 2 additions & 0 deletions core/src/main/java/com/google/errorprone/scanner/BuiltInCheckerSuppliers.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@
import com.google.errorprone.bugpatterns.AssertionFailureIgnored;
import com.google.errorprone.bugpatterns.AsyncCallableReturnsNull;
import com.google.errorprone.bugpatterns.AsyncFunctionReturnsNull;
import com.google.errorprone.bugpatterns.AutoValueFinalMethods;
import com.google.errorprone.bugpatterns.BadAnnotationImplementation;
import com.google.errorprone.bugpatterns.BadComparable;
import com.google.errorprone.bugpatterns.BadImport;
Expand Down Expand Up @@ -492,6 +493,7 @@ public static ScannerSupplier errorChecks() {
AssertEqualsArgumentOrderChecker.class,
AssertThrowsMultipleStatements.class,
AssertionFailureIgnored.class,
AutoValueFinalMethods.class,
BadAnnotationImplementation.class,
BadComparable.class,
BadImport.class,
Expand Down
125 changes: 125 additions & 0 deletions core/src/test/java/com/google/errorprone/bugpatterns/AutoValueFinalMethodsTest.java
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,125 @@
/*
* 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 com.google.errorprone.BugCheckerRefactoringTestHelper;
import com.google.errorprone.CompilationTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
* Unit tests for {@link AutoValueFinalMethods} bug pattern.
*
* @author bhagwani@google.com (Sumit Bhagwani)
*/
@RunWith(JUnit4.class)
public class AutoValueFinalMethodsTest {
private final BugCheckerRefactoringTestHelper testHelper =
BugCheckerRefactoringTestHelper.newInstance(new AutoValueFinalMethods(), getClass());
private final CompilationTestHelper compilationHelper =
CompilationTestHelper.newInstance(AutoValueFinalMethods.class, getClass());

@Test
public void testFinalAdditionToEqHcTs() throws Exception {
testHelper
.addInputLines(
"in/Test.java",
"import com.google.auto.value.AutoValue;",
"@AutoValue",
"abstract class Test {",
" abstract String valueOne();",
" abstract String valueTwo();",
" static Test create(String valueOne, String valueTwo) {",
" return null;",
" }",
" @Override",
" public int hashCode() {",
" return 1;",
" }",
" @Override",
" public String toString() {",
" return \"Hakuna Matata\";",
" }",
" @Override",
" public boolean equals(Object obj) {",
" return true;",
" }",
"}")
.addOutputLines(
"out/Test.java",
"import com.google.auto.value.AutoValue;",
"@AutoValue",
"abstract class Test {",
" abstract String valueOne();",
" abstract String valueTwo();",
" static Test create(String valueOne, String valueTwo) {",
" return null;",
" }",
" @Override",
" public final int hashCode() {",
" return 1;",
" }",
" @Override",
" public final String toString() {",
" return \"Hakuna Matata\";",
" }",
" @Override",
" public final boolean equals(Object obj) {",
" return true;",
" }",
"}")
.doTest();
}

@Test
public void testNegativeCases() throws Exception {
compilationHelper
.addSourceLines(
"out/Test.java",
"import com.google.auto.value.AutoValue;",
"import com.google.auto.value.extension.memoized.Memoized;",
"@AutoValue",
"abstract class Test {",
" abstract String valueOne();",
" abstract String valueTwo();",
" static Test create(String valueOne, String valueTwo) {",
" return null;",
" }",
" @Override",
" public abstract int hashCode(); ",
" @Override",
" public final String toString() {",
" return \"Hakuna Matata\";",
" }",
" @Override",
" public final boolean equals(Object obj) {",
" return true;",
" }",
" private int privateNonEqTsHcMethod() {",
" return 2;",
" }",
" public final String publicFinalNonEqTsHcMethod() {",
" return \"Hakuna Matata\";",
" }",
" public boolean publicNonEqTsHcMethod(Object obj) {",
" return true;",
" }",
"}")
.doTest();
}
}
7 changes: 7 additions & 0 deletions docs/bugpattern/AutoValueFinalMethods.md
View file
Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
Consider that other developers will try to read and understand your value class
while looking only at your hand-written class, not the actual (generated)
implementation class. If you mark your concrete methods final, they won't have
to wonder whether the generated subclass might be overriding them. This is
especially helpful if you are underriding equals, hashCode or toString!

Reference: https://github.com/google/auto/blob/master/value/userguide/practices.md#mark-all-concrete-methods-final

0 comments on commit a5cb666

Please sign in to comment.