PrimitiveArrayPassedToVarargsMethod
Passing a primitive array to a varargs method is usually wrong

Category
Severity
WARNING
Maturity

The problem

When you pass a primitive array as the only argument to a varargs method, the primitive array is autoboxed into a single-element Object array. This is usually not what was intended.

Suppression

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


Positive examples

PrimitiveArrayPassedToVarargsMethodPositiveCases.java

/*
* Copyright 2014 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.Arrays;

/** @author eaftan@google.com (Eddie Aftandilian) */
public class PrimitiveArrayPassedToVarargsMethodPositiveCases {

public void objectVarargsMethod(Object... objs) {}

public <T> void genericVarargsMethod(T... genericArrays) {}

public void objectVarargsMethodWithMultipleParams(Object obj1, Object... objs) {}

public void doIt() {
int[] intArray = {1, 2, 3};

// BUG: Diagnostic contains:
objectVarargsMethod(intArray);

// BUG: Diagnostic contains:
genericVarargsMethod(intArray);

// BUG: Diagnostic contains:
objectVarargsMethodWithMultipleParams(new Object(), intArray);

// BUG: Diagnostic contains:
Arrays.asList(intArray);
}
}

Negative examples

PrimitiveArrayPassedToVarargsMethodNegativeCases.java

/*
* Copyright 2014 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;


/** @author eaftan@google.com (Eddie Aftandilian) */
public class PrimitiveArrayPassedToVarargsMethodNegativeCases {

public void intVarargsMethod(int... ints) {}

public void intArrayVarargsMethod(int[]... intArrays) {}

public void objectVarargsMethodWithMultipleParams(Object obj1, Object... objs) {}

public void doIt() {
int[] intArray = {1, 2, 3};

intVarargsMethod(intArray);
intArrayVarargsMethod(intArray);
objectVarargsMethodWithMultipleParams(new Object());
}
}