Make FragmentNotInstantiable accept additional Fragment classes.

RELNOTES: FragmentNotInstantiable now accepts additional Fragment
classes.

MOE_MIGRATED_REVID=152717561

core/src/main/java/com/google/errorprone/bugpatterns/android/FragmentNotInstantiable.java

@@ -28,6 +28,7 @@
 import static javax.lang.model.element.Modifier.PUBLIC;
 import static javax.lang.model.element.NestingKind.MEMBER;
 
+import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -39,6 +40,7 @@
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.Tree;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /** @author avenet@google.com (Arnaud J. Venet) */
 @BugPattern(
@@ -59,8 +61,29 @@ public class FragmentNotInstantiable extends BugChecker implements ClassTreeMatc
   // platforms prior to Android 3.0.
   private static final String FRAGMENT_CLASS_V4 = "android.support.v4.app.Fragment";
 
-  private static final Matcher<ClassTree> FRAGMENT_MATCHER =
-      allOf(kindIs(CLASS), anyOf(isSubtypeOf(FRAGMENT_CLASS), isSubtypeOf(FRAGMENT_CLASS_V4)));
+  private final ImmutableSet<String> fragmentClasses;
+  private final Matcher<ClassTree> fragmentMatcher;
+
+  public FragmentNotInstantiable() {
+    this(ImmutableSet.of());
+  }
+
+  protected FragmentNotInstantiable(Iterable<String> additionalFragmentClasses) {
+    fragmentClasses =
+        ImmutableSet.<String>builder()
+            .add(FRAGMENT_CLASS)
+            .add(FRAGMENT_CLASS_V4)
+            .addAll(additionalFragmentClasses)
+            .build();
+    fragmentMatcher =
+        allOf(
+            kindIs(CLASS),
+            anyOf(
+                fragmentClasses
+                    .stream()
+                    .map(fragmentClass -> isSubtypeOf(fragmentClass))
+                    .collect(Collectors.toList())));
+  }
 
   private Description buildErrorMessage(Tree tree, String explanation) {
     Description.Builder description = buildDescription(tree);
@@ -70,12 +93,12 @@ private Description buildErrorMessage(Tree tree, String explanation) {
 
   @Override
   public Description matchClass(ClassTree classTree, VisitorState state) {
-    if (!FRAGMENT_MATCHER.matches(classTree, state)) {
+    if (!fragmentMatcher.matches(classTree, state)) {
       return Description.NO_MATCH;
     }
 
     String className = ASTHelpers.getSymbol(classTree).toString();
-    if (className.equals(FRAGMENT_CLASS) || className.equals(FRAGMENT_CLASS_V4)) {
+    if (fragmentClasses.contains(className)) {
       // Do not check the base class declarations (or their stubs).
       return Description.NO_MATCH;
     }

core/src/test/java/com/google/errorprone/bugpatterns/android/FragmentNotInstantiableTest.java

@@ -16,32 +16,68 @@
 
 package com.google.errorprone.bugpatterns.android;
 
+import static com.google.errorprone.BugPattern.Category.ANDROID;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.BugPattern;
 import com.google.errorprone.CompilationTestHelper;
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 
-/**
- * @author avenet@google.com (Arnaud J. Venet)
- */
+/** @author avenet@google.com (Arnaud J. Venet) */
 @RunWith(JUnit4.class)
 public class FragmentNotInstantiableTest {
-  private CompilationTestHelper compilationHelper;
-
-  @Before
-  public void setUp() {
-    compilationHelper =
-        CompilationTestHelper.newInstance(FragmentNotInstantiable.class, getClass());
+  /** Used for testing a custom FragmentNotInstantiable. */
+  @BugPattern(
+    name = "CustomFragmentNotInstantiable",
+    summary =
+        "Subclasses of CustomFragment must be instantiable via Class#newInstance():"
+            + " the class must be public, static and have a public nullary constructor",
+    category = ANDROID,
+    severity = WARNING
+  )
+  public static class CustomFragmentNotInstantiable extends FragmentNotInstantiable {
+    public CustomFragmentNotInstantiable() {
+      super(ImmutableSet.of("com.google.errorprone.bugpatterns.android.testdata.CustomFragment"));
+    }
   }
 
   @Test
   public void testPositiveCases() throws Exception {
-    compilationHelper.addSourceFile("FragmentNotInstantiablePositiveCases.java").doTest();
+    createCompilationTestHelper(FragmentNotInstantiable.class)
+        .addSourceFile("FragmentNotInstantiablePositiveCases.java")
+        .doTest();
   }
 
   @Test
   public void testNegativeCase() throws Exception {
-    compilationHelper.addSourceFile("FragmentNotInstantiableNegativeCases.java").doTest();
+    createCompilationTestHelper(FragmentNotInstantiable.class)
+        .addSourceFile("FragmentNotInstantiableNegativeCases.java")
+        .doTest();
+  }
+
+  @Test
+  public void testPositiveCases_custom() throws Exception {
+    createCompilationTestHelper(CustomFragmentNotInstantiable.class)
+        .addSourceFile("FragmentNotInstantiablePositiveCases.java")
+        .addSourceFile("CustomFragment.java")
+        .addSourceFile("CustomFragmentNotInstantiablePositiveCases.java")
+        .doTest();
+  }
+
+  @Test
+  public void testNegativeCase_custom() throws Exception {
+    createCompilationTestHelper(CustomFragmentNotInstantiable.class)
+        .addSourceFile("FragmentNotInstantiableNegativeCases.java")
+        .addSourceFile("CustomFragment.java")
+        .addSourceFile("CustomFragmentNotInstantiableNegativeCases.java")
+        .doTest();
+  }
+
+  private CompilationTestHelper createCompilationTestHelper(
+      Class<? extends FragmentNotInstantiable> bugCheckerClass) {
+    return CompilationTestHelper.newInstance(bugCheckerClass, getClass());
   }
 }

core/src/test/java/com/google/errorprone/bugpatterns/android/testdata/CustomFragment.java

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2017 Google 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.google.errorprone.bugpatterns.android.testdata;
+
+/** @author jasonlong@google.com (Jason Long) */
+public class CustomFragment {}

core/src/test/java/com/google/errorprone/bugpatterns/android/testdata/CustomFragmentNotInstantiableNegativeCases.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2017 Google 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.google.errorprone.bugpatterns.android.testdata;
+
+/**
+ * @author jasonlong@google.com (Jason Long)
+ */
+public class CustomFragmentNotInstantiableNegativeCases {
+  public static class NotAFragment1 {
+    public NotAFragment1(int x) {}
+  }
+
+  public static class NotAFragment2 {
+    private NotAFragment2() {}
+  }
+
+  private static class NotAFragment3 {}
+
+  public class NotAFragment4 {}
+
+  private abstract class AbstractFragment extends CustomFragment {
+    public AbstractFragment(int x) {}
+  }
+
+  public static class MyFragment extends CustomFragment {
+    private int a;
+
+    public int value() {
+      return a;
+    }
+  }
+
+  public static class DerivedFragment extends MyFragment {}
+
+  public static class MyFragment2 extends CustomFragment {
+    public MyFragment2() {}
+
+    public MyFragment2(int x) {}
+  }
+
+  public static class DerivedFragment2 extends MyFragment2 {
+    public DerivedFragment2() {}
+
+    public DerivedFragment2(boolean b) {}
+  }
+
+  public static class EnclosingClass {
+    public static class InnerFragment extends CustomFragment {
+      public InnerFragment() {}
+    }
+  }
+
+  interface AnInterface {
+    public class ImplicitlyStaticInnerFragment extends CustomFragment {}
+
+    class ImplicitlyStaticAndPublicInnerFragment extends CustomFragment {}
+  }
+}

core/src/test/java/com/google/errorprone/bugpatterns/android/testdata/CustomFragmentNotInstantiablePositiveCases.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2017 Google 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.google.errorprone.bugpatterns.android.testdata;
+
+/**
+ * @author jasonlong@google.com (Jason Long)
+ */
+public class CustomFragmentNotInstantiablePositiveCases {
+  // BUG: Diagnostic contains: public
+  static class PrivateFragment extends CustomFragment {
+    public PrivateFragment() {}
+  }
+
+  public static class PrivateConstructor extends CustomFragment {
+    // BUG: Diagnostic contains: public
+    PrivateConstructor() {}
+  }
+
+  // BUG: Diagnostic contains: nullary constructor
+  public static class NoConstructor extends CustomFragment {
+    public NoConstructor(int x) {}
+  }
+
+  // BUG: Diagnostic contains: nullary constructor
+  public static class NoConstructorV4 extends android.support.v4.app.Fragment {
+    public NoConstructorV4(int x) {}
+  }
+
+  public static class ParentFragment extends CustomFragment {
+    public ParentFragment() {}
+  }
+
+  public static class ParentFragmentV4 extends android.support.v4.app.Fragment {
+    public ParentFragmentV4() {}
+  }
+
+  // BUG: Diagnostic contains: nullary constructor
+  public static class DerivedFragmentNoConstructor extends ParentFragment {
+    public DerivedFragmentNoConstructor(int x) {}
+  }
+
+  // BUG: Diagnostic contains: nullary constructor
+  public static class DerivedFragmentNoConstructorV4 extends ParentFragmentV4 {
+    public DerivedFragmentNoConstructorV4(boolean b) {}
+  }
+
+  public class EnclosingClass {
+    // BUG: Diagnostic contains: static
+    public class InnerFragment extends CustomFragment {
+      public InnerFragment() {}
+    }
+
+    public CustomFragment create1() {
+      // BUG: Diagnostic contains: public
+      return new CustomFragment() {};
+    }
+
+    public CustomFragment create2() {
+      // BUG: Diagnostic contains: public
+      class LocalFragment extends CustomFragment {}
+      return new LocalFragment();
+    }
+  }
+}