RFR: 8283075: Bad IllegalArgumentException message for out of range rank from ClassDesc.arrayType(int) [v2]

[liach]

On Tue, 15 Mar 2022 17:09:03 GMT, Joe Darcy <darcy at openjdk.org> wrote:

>> src/java.base/share/classes/java/lang/constant/ClassDesc.java line 185:
>> 
>>> 183:             netRank = Math.addExact(currentDepth, rank);
>>> 184:             if (netRank > ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS) {
>>> 185:                 throw new IllegalArgumentException("rank: " + netRank +
>> 
>> This doesn’t need to use <code>[Math.addExact](<var>currentDepth</var>, <var>rank</var>)</code>, as <code><var>currentDepth</var></code> will always be in [0, 255], and <code><var>rank</var></code> here is confined to [1, 2<sup>31</sup>-1], so it’s possible to check for <code><var>netRank</var> < 0</code> and use <code>[Integer.toUnsignedString](<var>netRank</var>)</code> (or <code>[Integer.toUnsignedLong](<var>netRank</var>)</code> and let <code>[StringConcatFactory]</code> deal with it):
>> 
>> Suggestion:
>> 
>>             netRank = currentDepth + rank;
>>             if (netRank > ConstantUtils.MAX_ARRAY_TYPE_DESC_DIMENSIONS || netRank < 0) {
>>                 throw new IllegalArgumentException("rank: " + Integer.toUnsignedLong(netRank) +
>> 
>> 
>> [Integer.toUnsignedLong]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Integer.html#toUnsignedLong(int)
>> [Integer.toUnsignedString]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Integer.html#toUnsignedString(int)
>> [Math.addExact]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/Math.html#addExact(int,int)
>> [StringConcatFactory]: https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/invoke/StringConcatFactory.html
>
> Hmm. In this context, I think using addExact is clearer regarding the intention of the check. Thanks.

Notice the overflow case is already handled by the `ArithmeticException` caught in the larger try block.

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PR: https://git.openjdk.java.net/jdk/pull/7812