InjectedConstructorAnnotations
Injected constructors cannot be optional nor have binding annotations

Severity
ERROR
Has Fix?
REQUIRES_HUMAN_ATTENTION

The problem

The constructor is annotated with @Inject(optional=true), or it is annotated with @Inject and a binding annotation. This will cause a Guice runtime error.

See [https://code.google.com/p/google-guice/wiki/InjectionPoints] for details.

Suppression

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


Positive examples

InjectedConstructorAnnotationsPositiveCases.java

/*
* 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.inject.testdata;

import com.google.inject.BindingAnnotation;
import com.google.inject.Inject;

/** A positive test case for InjectedConstructorAnnotation. */
public class InjectedConstructorAnnotationsPositiveCases {

/** A binding annotation. */
@BindingAnnotation
public @interface TestBindingAnnotation {
}

/** A class with an optionally injected constructor. */
public class TestClass1 {
// BUG: Diagnostic contains: @Inject public TestClass1
@Inject(optional = true) public TestClass1() {}
}

/** A class with an injected constructor that has a binding annotation. */
public class TestClass2 {
// BUG: Diagnostic contains: @Inject public TestClass2
@TestBindingAnnotation @Inject public TestClass2() {}
}

/** A class whose constructor is optionally injected and has a binding annotation. */
public class TestClass3 {
// BUG: Diagnostic contains: @Inject public TestClass3
@TestBindingAnnotation @Inject(optional = true) public TestClass3() {}
}
}

Negative examples

InjectedConstructorAnnotationsNegativeCases.java

/*
* 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.inject.testdata;

import com.google.inject.BindingAnnotation;
import com.google.inject.Inject;

/** A negative test case for InjectedConstructorAnnotation. */
public class InjectedConstructorAnnotationsNegativeCases {

private @interface TestAnnotation {}

@BindingAnnotation
private @interface TestBindingAnnotation {}

/** A class with a constructor that has no annotations. */
public class TestClass1 {
public TestClass1() {}
}

/** A class with a constructor that has a binding Annotation. */
public class TestClass2 {
@TestBindingAnnotation
public TestClass2() {}
}

/** A class with an injected constructor. */
public class TestClass3 {
@Inject
public TestClass3() {}
}

/** A class with an injected constructor that has a non-binding annotation. */
public class TestClass4 {
@Inject
@TestAnnotation
public TestClass4() {}
}
}