/*
 * Copyright 2013 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.common.collect.ImmutableList;
import com.google.errorprone.CompilationTestHelper;
import org.junit.Ignore;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * @author flx@google.com (Felix Berger)
 */
@RunWith(JUnit4.class)
@Ignore("b/130670448")
public final class ImpossibleNullComparisonTest {

  private final CompilationTestHelper compilationHelper =
      CompilationTestHelper.newInstance(ImpossibleNullComparison.class, getClass());

  @Test
  public void scalarCases() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "class Test {",
            "  void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    // BUG: Diagnostic contains: message.hasMessage()",
            "    if (message.getMessage() != null) {}",
            "    // BUG: Diagnostic contains: !message.hasMessage()",
            "    if (message.getMessage() == null) {}",
            "    // BUG: Diagnostic contains: message.hasMessage()",
            "    if (null != message.getMessage()) {}",
            "    // BUG: Diagnostic contains: message.getMessage().hasField()",
            "    if (message.getMessage().getField() != null) {}",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void listCases() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestFieldProtoMessage;",
            "class Test {",
            "  void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    TestFieldProtoMessage field = message.getMessage();",
            "    // BUG: Diagnostic contains: !message.getMultiFieldList().isEmpty()",
            "    if (message.getMultiFieldList() != null) {}",
            "    // BUG: Diagnostic contains: message.getMultiFieldList().isEmpty()",
            "    if (null == message.getMultiFieldList()) {}",
            "    // BUG: Diagnostic contains: message.getMultiFieldCount() > 1",
            "    if (message.getMultiField(1) != null) {}",
            "    // BUG: Diagnostic contains: message.getMultiFieldCount() <= 1",
            "    if (message.getMultiField(1) == null) {}",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void intermediateVariable() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestFieldProtoMessage;",
            "import java.util.List;",
            "class Test {",
            "  void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    TestFieldProtoMessage field = message.getMessage();",
            "    List<TestFieldProtoMessage> fields = message.getMultiFieldList();",
            "    // BUG: Diagnostic contains: message.hasMessage()",
            "    if (field != null) {}",
            "    // BUG: Diagnostic contains: !message.getMultiFieldList().isEmpty()",
            "    if (fields != null) {}",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void negativeCases() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "class Test {",
            "  public void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    Object object = new Object();",
            "    if (message.getMessage() != object) {}",
            "    if (object != message.getMessage()) {}",
            "    if (message.getMessage().getField() != object) {}",
            "    if (message.getMultiFieldList() != object) {}",
            "    if (object == message.getMultiFieldList()) {}",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void proto3() {
    compilationHelper
        .addSourceLines(
            "TestProto3.java",
            "import com.google.errorprone.bugpatterns.proto.Proto3Test.TestProto3Message;",
            "public class TestProto3 {",
            "  public boolean doIt(TestProto3Message proto3Message) {",
            "    // BUG: Diagnostic matches: NO_FIX",
            "    return proto3Message.getMyString() == null;",
            "  }",
            "}")
        .expectErrorMessage("NO_FIX", input -> !input.contains("hasMyString()"))
        .doTest();
  }

  @Test
  public void messageOrBuilderGetField() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.Descriptors.FieldDescriptor;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "public class Test {",
            "  public boolean doIt(TestProtoMessage mob, FieldDescriptor f) {",
            "    // BUG: Diagnostic contains:",
            "    return mob.getField(f) == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void messageOrBuilderGetFieldCast() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.Descriptors.FieldDescriptor;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "public class Test {",
            "  public boolean doIt(TestProtoMessage mob, FieldDescriptor f) {",
            "    String s = ((String) mob.getField(f));",
            "    // BUG: Diagnostic contains:",
            "    return s == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void extendableMessageGetExtension1param() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.ExtensionLite;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "public class Test {",
            "  public void test(TestProtoMessage e, ExtensionLite extensionLite) {",
            "    // BUG: Diagnostic contains:",
            "    boolean a = e.getExtension(extensionLite) == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void messageOrBuilderGetRepeatedField() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.Descriptors.FieldDescriptor;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "public class Test {",
            "  public void doIt(TestProtoMessage mob, FieldDescriptor f) {",
            "    // BUG: Diagnostic contains:",
            "    boolean a = mob.getRepeatedField(f, 0) == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void extendableMessageGetExtension2param() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.ExtensionLite;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "public class Test {",
            "  public void test(TestProtoMessage e, ExtensionLite extensionLite) {",
            "    // BUG: Diagnostic contains:",
            "    boolean a = e.getExtension(extensionLite, 0) == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void repeated() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.ExtensionLite;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestFieldProtoMessage;",
            "import java.util.List;",
            "public class Test {",
            " public void test(ExtensionLite<TestProtoMessage,",
            "  List<TestFieldProtoMessage>> e, TestProtoMessage message) {",
            "    // BUG: Diagnostic contains:",
            "    boolean y = message.getExtension(e) == null;",
            " }",
            "}")
        .doTest();
  }

  @Test
  public void repeated2() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.protobuf.Extension.MessageType;",
            "import com.google.protobuf.ExtensionLite;",
            "import com.google.protobuf.GeneratedMessage;",
            "import com.sun.tools.javac.code.Type;",
            "import com.google.common.collect.ImmutableList;",
            "import java.util.List;",
            "public class Test {",
            "public static <MessageType extends GeneratedMessage.ExtendableMessage<MessageType>,",
            "Type extends GeneratedMessage>",
            "List<Type> getRepeatedExtensionObjects(",
            "GeneratedMessage.ExtendableMessage<MessageType> mob,",
            " ExtensionLite<MessageType, List<Type>> extension) {",
            " ImmutableList.Builder extensionList = ImmutableList.builder();",
            " int extensionCount = mob.getExtensionCount(extension);",
            " for (int extensionIndex = 0; extensionIndex < extensionCount; ++extensionIndex) {",
            "  // BUG: Diagnostic contains:",
            "  boolean y = mob.getExtension(extension) == null;",
            "  extensionList.add(mob.getExtension(extension));",
            " }",
            " return extensionList.build();",
            "}",
            "}")
        .addModules("jdk.compiler/com.sun.tools.javac.code")
        .doTest();
  }

  @Test
  public void preconditions() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import static com.google.common.base.Preconditions.checkNotNull;",
            "import static com.google.common.base.Verify.verifyNotNull;",
            "import static java.util.Objects.requireNonNull;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestFieldProtoMessage;",
            "import java.util.List;",
            "class Test {",
            "  void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    TestFieldProtoMessage field = message.getMessage();",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(field);",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(message.getMessage());",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    verifyNotNull(message.getMessage());",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(message.getMultiFieldList());",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(message.getMessage(), new Object());",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(message.getMultiFieldList(), new Object());",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(message.getMessage(), \"%s\", new Object());",
            "    // BUG: Diagnostic contains: This value cannot be null",
            "    // remove this line",
            "    checkNotNull(message.getMultiFieldList(), \"%s\", new Object());",
            "    // BUG: Diagnostic contains: fieldMessage = message.getMessage();",
            "    TestFieldProtoMessage fieldMessage = checkNotNull(message.getMessage());",
            "    // BUG: Diagnostic contains: fieldMessage2 = message.getMessage()",
            "    TestFieldProtoMessage fieldMessage2 = checkNotNull(message.getMessage(), \"M\");",
            "    // BUG: Diagnostic contains: message.getMessage().toString();",
            "    checkNotNull(message.getMessage()).toString();",
            "    // BUG: Diagnostic contains: message.getMessage().toString();",
            "    checkNotNull(message.getMessage(), \"Message\").toString();",
            "    // BUG: Diagnostic contains: TestFieldProtoMessage fieldCopy = field;",
            "    TestFieldProtoMessage fieldCopy = requireNonNull(field);",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void assertions() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import static com.google.common.truth.Truth.assertThat;",
            "import static org.junit.Assert.assertNotNull;",
            "import com.google.common.truth.extensions.proto.ProtoTruth;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestFieldProtoMessage;",
            "import java.util.List;",
            "class Test {",
            "  void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    TestFieldProtoMessage field = message.getMessage();",
            "    // BUG: Diagnostic contains: assertTrue(\"Message\", message.hasMessage());",
            "    assertNotNull(\"Message\", message.getMessage());",
            "    // BUG: Diagnostic contains: assertThat(message.hasMessage()).isTrue()",
            "    assertThat(message.getMessage()).isNotNull();",
            "    // BUG: Diagnostic contains: assertThat(message.hasMessage()).isTrue()",
            "    ProtoTruth.assertThat(message.getMessage()).isNotNull();",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void assertions_negative() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import static com.google.common.truth.Truth.assertThat;",
            "import static org.junit.Assert.assertNotNull;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestFieldProtoMessage;",
            "import java.util.List;",
            "class Test {",
            "  void test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    TestFieldProtoMessage field = message.getMessage();",
            "    assertNotNull(\"Message\", message.getMessage());",
            "    assertThat(message.getMessage()).isNotNull();",
            "  }",
            "}")
        .setArgs(ImmutableList.of("-XepOpt:ProtoFieldNullComparison:MatchTestAssertions=false"))
        .doTest();
  }

  @Test
  public void optional() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import java.util.Optional;",
            "class Test {",
            "  Optional<?> test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    // BUG: Diagnostic contains: Optional.of(message.getMessage())",
            "    return Optional.ofNullable(message.getMessage());",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void guavaOptional() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
            "import java.util.Optional;",
            "class Test {",
            "  Optional<?> test() {",
            "    TestProtoMessage message = TestProtoMessage.newBuilder().build();",
            "    // BUG: Diagnostic contains: Optional.of(message.getMessage())",
            "    return Optional.ofNullable(message.getMessage());",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void optionalGet() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import java.util.Optional;",
            "public class Test {",
            "  public boolean o(Optional<String> o) {",
            "    // BUG: Diagnostic contains: o.isEmpty()",
            "    return o.get() == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void guavaOptionalGet() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.common.base.Optional;",
            "public class Test {",
            "  public boolean o(Optional<String> o) {",
            "    // BUG: Diagnostic contains: !o.isPresent()",
            "    return o.get() == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void multimapGet() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.common.collect.Multimap;",
            "public class Test {",
            "  public boolean o(Multimap<String, String> m) {",
            "    // BUG: Diagnostic contains: !m.containsKey(\"foo\")",
            "    return m.get(\"foo\") == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void listMultimapGet() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.common.collect.ListMultimap;",
            "public class Test {",
            "  public boolean o(ListMultimap<String, String> m) {",
            "    // BUG: Diagnostic contains: !m.containsKey(\"foo\")",
            "    return m.get(\"foo\") == null;",
            "  }",
            "}")
        .doTest();
  }

  @Test
  public void tables() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            "import com.google.common.collect.Table;",
            "public class Test {",
            "  public void o(Table<String, String, String> t) {",
            "    // BUG: Diagnostic contains: !t.containsRow(\"foo\")",
            "    boolean b1 = t.row(\"foo\") == null;",
            "    // BUG: Diagnostic contains: !t.containsColumn(\"foo\")",
            "    boolean b2 = t.column(\"foo\") == null;",
            "  }",
            "}")
        .doTest();
  }
}
