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Leonid Shalupovandintellij-monorepo-bot
40795fe787
GitOrigin-RevId: 8b2b63fc6db476ca0c2cfe5cadd84db6c4236d0f
49 lines
1.8 KiB
HTML
49 lines
1.8 KiB
HTML
<html>
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<body>
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Reports subtraction in
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<code>compareTo()</code> methods and methods implementing <code>java.util.Comparator.compare()</code>.
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<p>
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While it is a common idiom to
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use the results of integer subtraction as the result of a <code>compareTo()</code>
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method, this construct may cause subtle and difficult bugs in cases of integer overflow.
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Comparing the integer values directly and returning <code>-1</code>, <code>0</code>, or <code>1</code> is a better practice in most cases.
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</p>
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<p>
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Subtraction on floating point values that is immediately cast to integral type is also reported because precision loss is possible due to
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rounding.
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</p>
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<p>
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The inspection doesn't report when it's statically determined that value ranges are limited, and overflow never occurs.
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Additionally, subtraction on <code>int</code> numbers greater than or equal to <code>0</code> will never overflow.
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Therefore, this inspection tries not to warn in those cases.
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</p>
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<p>
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Methods that always return zero or greater can be marked with the
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<code>javax.annotation.Nonnegative</code> annotation or specified in this inspection's options.
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</p>
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<p><b>Example:</b></p>
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<pre><code>
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class DoubleHolder implements Comparable<DoubleHolder> {
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double d;
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public int compareTo(DoubleHolder that) {
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return (int)(this.d - that.d);
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}
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}
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</code></pre>
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<p>A no-warning example because <code>String.length()</code> is known to be non-negative:</p>
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<pre><code>
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class A implements Comparable<A> {
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final String s = "";
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public int compareTo(A a) {
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return s.length() - a.s.length();
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}
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}
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</code></pre>
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<!-- tooltip end -->
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<p>
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Use the options to list methods that are safe to use inside a subtraction.
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Methods are safe when they return an <code>int</code> value that is always greater than or equal to <code>0</code>.
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</p>
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</body>
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</html> |