Migrate VisibleForTesting validation from checkstyle to errorprone

README.md

@@ -188,6 +188,7 @@ Safe Logging can be found at [github.com/palantir/safe-logging](https://github.c
 - `LoggerEnclosingClass`: Loggers created using getLogger(Class<?>) must reference their enclosing class.
 - `UnnecessaryLambdaArgumentParentheses`: Lambdas with a single parameter do not require argument parentheses.
 - `RawTypes`: Avoid raw types; add appropriate type parameters if possible.
+- `VisibleForTestingPackagePrivate`: `@VisibleForTesting` members should be package-private.
 
 ### Programmatic Application
 

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

@@ -0,0 +1,75 @@
+/*
+ * (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.common.annotations.VisibleForTesting;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+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.sun.source.tree.ClassTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.tree.VariableTree;
+import javax.lang.model.element.Modifier;
+
+/** Development Practices: Writing good unit tests. */
+@AutoService(BugChecker.class)
+@BugPattern(
+        name = "VisibleForTestingPackagePrivate",
+        link = "https://github.com/palantir/gradle-baseline#baseline-error-prone-checks",
+        linkType = BugPattern.LinkType.CUSTOM,
+        severity = BugPattern.SeverityLevel.WARNING,
+        summary = "@VisibleForTesting members should be package-private.")
+public final class VisibleForTestingPackagePrivate extends BugChecker
+        implements BugChecker.ClassTreeMatcher, BugChecker.MethodTreeMatcher, BugChecker.VariableTreeMatcher {
+
+    private static final Matcher<Tree> matcher = Matchers.allOf(
+            Matchers.hasAnnotation(VisibleForTesting.class),
+            Matchers.anyOf(
+                    MoreMatchers.hasExplicitModifier(Modifier.PROTECTED),
+                    MoreMatchers.hasExplicitModifier(Modifier.PUBLIC)));
+
+    private Description match(Tree tree, VisitorState state) {
+        if (matcher.matches(tree, state)) {
+            return buildDescription(tree)
+                    // This may break code that references the visible component, so it should not
+                    // be applied by default.
+                    .addFix(SuggestedFixes.removeModifiers(tree, state, Modifier.PROTECTED, Modifier.PUBLIC))
+                    .build();
+        }
+        return Description.NO_MATCH;
+    }
+
+    @Override
+    public Description matchMethod(MethodTree tree, VisitorState state) {
+        return match(tree, state);
+    }
+
+    @Override
+    public Description matchClass(ClassTree tree, VisitorState state) {
+        return match(tree, state);
+    }
+
+    @Override
+    public Description matchVariable(VariableTree tree, VisitorState state) {
+        return match(tree, state);
+    }
+}

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

@@ -0,0 +1,134 @@
+/*
+ * (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 VisibleForTestingPackagePrivateTest {
+
+    @Test
+    void testMethod() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public class Test {",
+                        "  @VisibleForTesting",
+                        "  public void foo() {}",
+                        "  @VisibleForTesting",
+                        "  public static void staticFoo() {}",
+                        "  @VisibleForTesting",
+                        "  protected void bar() {}",
+                        "  public void baz() {}",
+                        "  public static void staticBaz() {}",
+                        "  protected void bang() {}",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public class Test {",
+                        "  @VisibleForTesting",
+                        "  void foo() {}",
+                        "  @VisibleForTesting",
+                        "  static void staticFoo() {}",
+                        "  @VisibleForTesting",
+                        "  void bar() {}",
+                        "  public void baz() {}",
+                        "  public static void staticBaz() {}",
+                        "  protected void bang() {}",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    void testField() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public class Test {",
+                        "  @VisibleForTesting",
+                        "  public int foo = 1;",
+                        "  public int bar = 1;",
+                        "  @VisibleForTesting",
+                        "  public static final int FOO = 1;",
+                        "  public static final int BAR = 1;",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public class Test {",
+                        "  @VisibleForTesting",
+                        "  int foo = 1;",
+                        "  public int bar = 1;",
+                        "  @VisibleForTesting",
+                        "  static final int FOO = 1;",
+                        "  public static final int BAR = 1;",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    void testType() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public class Test {",
+                        "  @VisibleForTesting",
+                        "  public static final class Foo {}",
+                        "  public static final class Bar {}",
+                        "}")
+                .addOutputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public class Test {",
+                        "  @VisibleForTesting",
+                        "  static final class Foo {}",
+                        "  public static final class Bar {}",
+                        "}")
+                .doTest();
+    }
+
+    @Test
+    void testNegativeInterfaceMethods() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public interface Test {",
+                        "  @VisibleForTesting",
+                        "  default void foo() {}",
+                        "  @VisibleForTesting",
+                        "  static void staticFoo() {}",
+                        "}")
+                .expectUnchanged()
+                .doTest();
+    }
+
+    @Test
+    void testNegativeInterfaceFields() {
+        fix().addInputLines(
+                        "Test.java",
+                        "import com.google.common.annotations.VisibleForTesting;",
+                        "public interface Test {",
+                        "  @VisibleForTesting",
+                        "  int FOO = 5;",
+                        "}")
+                .expectUnchanged()
+                .doTest();
+    }
+
+    private RefactoringValidator fix() {
+        return RefactoringValidator.of(new VisibleForTestingPackagePrivate(), getClass());
+    }
+}

changelog/@unreleased/pr-1253.v2.yml

@@ -0,0 +1,5 @@
+type: improvement
+improvement:
+  description: Migrate VisibleForTesting validation from checkstyle to errorprone
+  links:
+  - https://github.com/palantir/gradle-baseline/pull/1253

gradle-baseline-java-config/resources/checkstyle/checkstyle.xml

@@ -18,11 +18,6 @@
     <module name="NewlineAtEndOfFile"> <!-- Java Style Guide: Line ending: LF -->
         <property name="lineSeparator" value="lf"/>
     </module>
-    <module name="RegexpMultiline"> <!-- Development Practices: Writing good unit tests -->
-        <property name="fileExtensions" value="java"/>
-        <property name="format" value="@VisibleForTesting\s+(protected|public)"/>
-        <property name="message" value="@VisibleForTesting members should be package-private."/>
-    </module>
     <module name="RegexpSingleline"> <!-- No reference needed as this is evident. -->
         <property name="format" value="&lt;&lt;&lt;&lt;&lt;&lt;&lt;"/>
         <property name="message" value="Found (&lt;&lt;&lt;&lt;&lt;&lt;&lt;), so it looks like you had a merge conflict that compiles. Please fix it."/>