Implement DeprecatedGuavaObjects error-prone migration

README.md

@@ -195,6 +195,7 @@ Safe Logging can be found at [github.com/palantir/safe-logging](https://github.c
 - `ImplicitPublicBuilderConstructor`: Prevent builders from unintentionally leaking public constructors.
 - `ImmutablesBuilderMissingInitialization`: Prevent building Immutables.org builders when not all fields have been populated.
 - `UnnecessarilyQualified`: Types should not be qualified if they are also imported. 
+- `DeprecatedGuavaObjects`: `com.google.common.base.Objects` has been obviated by `java.util.Objects`.
 
 ### Programmatic Application
 

baseline-error-prone/src/main/java/com/palantir/baseline/errorprone/DeprecatedGuavaObjects.java

@@ -0,0 +1,70 @@
+/*
+ * (c) Copyright 2020 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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.palantir.baseline.errorprone;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.BugPattern.LinkType;
+import com.google.errorprone.BugPattern.SeverityLevel;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.matchers.method.MethodMatchers;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+
+@AutoService(BugChecker.class)
+@BugPattern(
+        name = "DeprecatedGuavaObjects",
+        link = "https://github.com/palantir/gradle-baseline#baseline-error-prone-checks",
+        linkType = LinkType.CUSTOM,
+        severity = SeverityLevel.WARNING,
+        summary = "The standard library java.util.Objects utilities replace Guava "
+                + "com.google.common.base.Objects in java 1.7 and beyond.")
+public final class DeprecatedGuavaObjects extends BugChecker implements BugChecker.MethodInvocationTreeMatcher {
+
+    private static final String GUAVA_OBJECTS_NAME = "com.google.common.base.Objects";
+    private static final String GUAVA_OBJECTS_EQUAL = GUAVA_OBJECTS_NAME + ".equal";
+    private static final String GUAVA_OBJECTS_HASH_CODE = GUAVA_OBJECTS_NAME + ".hashCode";
+    private static final String JAVA_OBJECTS_NAME = "java.util.Objects";
+    private static final Matcher<ExpressionTree> EQUAL_MATCHER = MethodMatchers.staticMethod()
+            .onClass("com.google.common.base.Objects")
+            .named("equal");
+    private static final Matcher<ExpressionTree> HASH_CODE_MATCHER = MethodMatchers.staticMethod()
+            .onClass("com.google.common.base.Objects")
+            .named("hashCode");
+
+    @Override
+    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+        boolean hashCode = HASH_CODE_MATCHER.matches(tree, state);
+        boolean equal = EQUAL_MATCHER.matches(tree, state);
+        if (hashCode || equal) {
+            return buildDescription(tree)
+                    .addFix(SuggestedFix.builder()
+                            .removeImport(GUAVA_OBJECTS_NAME)
+                            .removeStaticImport(GUAVA_OBJECTS_EQUAL)
+                            .removeStaticImport(GUAVA_OBJECTS_HASH_CODE)
+                            .addImport(JAVA_OBJECTS_NAME)
+                            .replace(tree.getMethodSelect(), equal ? "Objects.equals" : "Objects.hash")
+                            .build())
+                    .build();
+        }
+        return Description.NO_MATCH;
+    }
+}

baseline-error-prone/src/test/java/com/palantir/baseline/errorprone/DeprecatedGuavaObjectsTest.java

@@ -0,0 +1,56 @@
+/*
+ * (c) Copyright 2020 Palantir Technologies Inc. All rights reserved.
+ *
+ * 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.palantir.baseline.errorprone;
+
+import org.junit.jupiter.api.Test;
+
+class DeprecatedGuavaObjectsTest {
+
+    @Test
+    public void test() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.base.Objects;",
+                        "import static com.google.common.base.Objects.equal;",
+                        "public class Test {",
+                        "  void f(Object a, Object b) {",
+                        "    com.google.common.base.Objects.equal(a, b);",
+                        "    Objects.equal(a, b);",
+                        "    equal(a, b);",
+                        "    com.google.common.base.Objects.hashCode(a, b);",
+                        "    Objects.hashCode(a, b);",
+                        "  }",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import java.util.Objects;",
+                        "public class Test {",
+                        "  void f(Object a, Object b) {",
+                        "    Objects.equals(a, b);",
+                        "    Objects.equals(a, b);",
+                        "    Objects.equals(a, b);",
+                        "    Objects.hash(a, b);",
+                        "    Objects.hash(a, b);",
+                        "  }",
+                        "}")
+                .doTest();
+    }
+
+    private RefactoringValidator fix() {
+        return RefactoringValidator.of(new DeprecatedGuavaObjects(), getClass());
+    }
+}

changelog/@unreleased/pr-1521.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Implement DeprecatedGuavaObjects error-prone migration
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1521

gradle-baseline-java/src/main/groovy/com/palantir/baseline/extensions/BaselineErrorProneExtension.java

@@ -33,6 +33,7 @@ public class BaselineErrorProneExtension {
             // TODO(ckozak): re-enable pending scala check
             // "CatchSpecificity",
             "CollectionStreamForEach",
+            "DeprecatedGuavaObjects",
             "ExecutorSubmitRunnableFutureIgnored",
             "ExtendsErrorOrThrowable",
             "FinalClass",