FuzzyEqualsShouldNotBeUsedInEqualsMethod
DoubleMath.fuzzyEquals should never be used in an Object.equals() method

Category
Severity
ERROR
Maturity

The problem

From documentation: DoubleMath.fuzzyEquals is not transitive, so it is not suitable for use in Object#equals implementations.

Suppression

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


Positive examples

FuzzyEqualsShouldNotBeUsedInEqualsMethodPositiveCases.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 com.google.common.math.DoubleMath;

/** @author sulku@google.com (Marsela Sulku) */
public class FuzzyEqualsShouldNotBeUsedInEqualsMethodPositiveCases {

  public boolean equals(Object o) {
    // BUG: Diagnostic contains: DoubleMath.fuzzyEquals should never
    DoubleMath.fuzzyEquals(0.2, 9.3, 2.0);
    return true;
  }

  private class TestClass {

    public boolean equals(Object other) {
      double x = 0, y = 0, z = 0;
      // BUG: Diagnostic contains: DoubleMath.fuzzyEquals should never
      return DoubleMath.fuzzyEquals(x, y, z);
    }
  }
}

Negative examples

FuzzyEqualsShouldNotBeUsedInEqualsMethodNegativeCases.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 com.google.common.math.DoubleMath;

/** @author sulku@google.com (Marsela Sulku) */
public class FuzzyEqualsShouldNotBeUsedInEqualsMethodNegativeCases {
  public boolean equals() {
    return true;
  }

  private static class TestClass {
    public void test() {
      boolean t = DoubleMath.fuzzyEquals(0, 2, 0.3);
    }

    public boolean equals(Object other) {
      return true;
    }

    public boolean equals(Object other, double a) {
      return DoubleMath.fuzzyEquals(0, 1, 0.2);
    }
  }
}