RFR: 8331485: Odd Results when Parsing Scientific Notation with Large Exponent [v3]

[Naoto Sato]

On Mon, 6 May 2024 17:52:07 GMT, Justin Lu <jlu at openjdk.org> wrote:

>> Please review this PR which corrects an edge case bug for java.text.DecimalFormat that causes incorrect parsing results for strings with very large exponent values.
>> 
>> When parsing values with large exponents, if the value of the exponent exceeds `Integer.MAX_VALUE`, the parsed value  is equal to 0. If the value of the exponent exceeds `Long.MAX_VALUE`, the parsed value is equal to the mantissa. Both results are confusing and incorrect.
>> 
>> For example,
>> 
>> 
>> NumberFormat fmt = NumberFormat.getInstance(Locale.US);
>> fmt.parse(".1E2147483648"); // returns 0.0
>> fmt.parse(".1E9223372036854775808"); // returns 0.1
>> // For comparison
>> Double.parseDouble(".1E2147483648"); // returns Infinity
>> Double.parseDouble(".1E9223372036854775808"); // returns Infinity
>> 
>> 
>> After this change, both parse calls return `Double.POSITIVE_INFINITY` now.
>
> Justin Lu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address PP for exp > Long.MAX_VALUE + more exp test cases

test/jdk/java/text/Format/DecimalFormat/LargeExponentsTest.java line 57:

> 55:     @ParameterizedTest
> 56:     @MethodSource({"largeExponentValues", "smallExponentValues", "bugReportValues", "edgeCases"})
> 57:     public void overflowTest(String parseString, Double expectedValue) {

Since this is a regression test, it may be better having both 1-arg parse() and 2-arg parse() tested separately, instead of replacing.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19075#discussion_r1591405570