PreconditionsInvalidPlaceholder
Preconditions only accepts the %s placeholder in error message strings

Severity
WARNING
Tags
LikelyError
Has Fix?

The problem

The Guava Preconditions checks take error message template strings that look similar to format strings but only accept %s as a placeholder. This check points out places where there is a non-%s placeholder in a Preconditions error message template string and the number of arguments does not match the number of %s placeholders.

Suppression

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


Positive examples

PreconditionsInvalidPlaceholderPositiveCase1.java

/*
 * Copyright 2012 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.testdata;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.base.Preconditions;

public class PreconditionsInvalidPlaceholderPositiveCase1 {
  int foo;

  public void checkPositive(int x) {
    // BUG: Diagnostic contains: %s > 0
    checkArgument(x > 0, "%d > 0", x);
  }

  public void checkFoo() {
    // BUG: Diagnostic contains: foo must be equal to 0 but was %s
    Preconditions.checkState(foo == 0, "foo must be equal to 0 but was {0}", foo);
  }
}

Negative examples

PreconditionsInvalidPlaceholderNegativeCase1.java

/*
 * Copyright 2012 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.testdata;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.base.Preconditions;

public class PreconditionsInvalidPlaceholderNegativeCase1 {
  Integer foo;

  public void checkPositive(int x) {
    checkArgument(x > 0, "%s > 0", x);
  }

  public void checkTooFewArgs(int x) {
    checkArgument(x > 0, "%s %s", x);
  }

  public void checkFoo() {
    Preconditions.checkState(foo.intValue() == 0, "foo must be equal to 0 but was %s", foo);
  }

  public static void checkNotNull(Object foo, String bar, Object baz) {}

  public void checkSelf() {
    checkNotNull(foo, "Foo", this);
  }
}