OptionalNotPresent
One should not call optional.get() inside an if statement that checks !optional.isPresent

Category
Severity
WARNING
Maturity

The problem

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("OptionalNotPresent") to the enclosing element.


Positive examples

OptionalNotPresentPositiveCases.java

/*
* 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.testdata;

import java.util.Optional;

/** @author mariasam@google.com on 8/3/17. */
public class OptionalNotPresentPositiveCases {

public void test(Optional<String> testStr) {
// BUG: Diagnostic contains: Optional
if (!testStr.isPresent()) {
String str = testStr.get();
}
}

public void testMultipleStatements(Optional<String> optional) {
// BUG: Diagnostic contains: Optional
if (!optional.isPresent()) {
String test = "test";
String str = optional.get();
}
}

public void testNestedIf(Optional<String> optional) {
// BUG: Diagnostic contains: Optional
if (!optional.isPresent()) {
if (optional == Optional.of("")) {
String str = optional.get();
}
}
}

public void testAnd(Optional<String> optional) {
// BUG: Diagnostic contains: Optional
if (!optional.isPresent() && 7 == 7) {
String str = optional.get();
}
}
}

Negative examples

OptionalNotPresentNegativeCases.java

/*
* 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.testdata;

import java.util.Optional;
import java.util.function.Predicate;

/** Created by mariasam on 8/3/17. */
public class OptionalNotPresentNegativeCases {

// Test this doesn't trigger NullPointerException
private final Predicate<Optional<?>> asField = o -> !o.isPresent();

public void testBasic(Optional<String> optional) {
if (optional.get() != null) {
String str = optional.get();
}
}

public void testNested(Optional<String> optional) {
if (7 == 7) {
String str = optional.get();
if (!optional.isPresent()) {
System.out.println("test");
}
}
}

public void testOptional(Optional<String> optional) {
if (!optional.isPresent()) {
optional = Optional.of("value");
String str = optional.get();
}
}

public void afterIf(Optional<String> optional) {
if (!optional.isPresent()) {
optional = Optional.of("value");
}
String str = optional.get();
}

public void checkMultipleInIf(Optional<String> optional) {
if (!optional.isPresent() || 7 == 7) {
String str = optional.isPresent() ? optional.get() : "";
}
}

public void checkInIf(Optional<String> optional) {
if (!optional.isPresent()) {
fillUpOptional(optional);
String str = optional.get();
}
}

private void fillUpOptional(Optional<String> optional) {
optional = Optional.of("");
}
}