On Wed, 13 Mar 2024 13:12:54 GMT, Shaojin Wen <d...@openjdk.org> wrote:
>> If the input is "+" or "-" an exception will be thrown on line 583
>>
>> boolean isneg = c == '-'; // leading minus means negative
>> if (isneg || c == '+') {
>> c = val.charAt(++offset);
>> len--;
>> }
>
> if the input is "" an exception will be throw on line 579
>
> int offset = 0;
> char c = val.charAt(offset);
Relying on the upper bounds check of `charAt` doesn't work well with the
`CharArraySequence` whose `charAt` deliberately does not throw an IIOBE if the
array is longer than the provided length, ie, it'll look at chars beyond the
provided range. The examples I tested still end up as a NFE, but it's clear
from the cause that we're running past the length:
jshell> new BigDecimal(new char[] { '-', '1', 'e'}, 0, 1);
| Exception java.lang.NumberFormatException
| at BigDecimal.<init> (BigDecimal.java:754)
| at BigDecimal.<init> (BigDecimal.java:543)
| at BigDecimal.<init> (BigDecimal.java:518)
| at (#4:1)
| Caused by: java.lang.ArrayIndexOutOfBoundsException: Index 3 out of bounds
for length 3
| at BigDecimal$CharArraySequence.charAt (BigDecimal.java:559)
| at BigDecimal.parseExp (BigDecimal.java:772)
| at BigDecimal.<init> (BigDecimal.java:619)
| ...
Baseline/expected:
jshell> new BigDecimal(new char[] { '-', '1', 'e'}, 0, 1);
| Exception java.lang.NumberFormatException: No digits found.
| at BigDecimal.<init> (BigDecimal.java:635)
| at BigDecimal.<init> (BigDecimal.java:518)
| at (#1:1)
Having a check on `len > 0` is more robust - and I'd be surprised if avoiding a
redundant check on the loop entry is affecting performance?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/18177#discussion_r1523301252
