On Tue, 8 Dec 2020 06:14:35 GMT, Stuart Marks <sma...@openjdk.org> wrote:
>> This rewrites the doc of ArraysSupport.newLength, adds detail to the
>> exception message, and adds a test. In addition to some renaming and a bit
>> of refactoring of the actual code, I also made two changes of substance to
>> the code:
>>
>> 1. I fixed a problem with overflow checking. In the original code, if
>> oldLength and prefGrowth were both very large (say, Integer.MAX_VALUE), this
>> method could return a negative value. It turns out that writing tests helps
>> find bugs!
>>
>> 2. Under the old policy, if oldLength and minGrowth required a length above
>> SOFT_MAX_ARRAY_LENGTH but not above Integer.MAX_VALUE, this method would
>> return Integer.MAX_VALUE. That doesn't make any sense, because attempting to
>> allocate an array of that length will almost certainly cause the Hotspot to
>> throw OOME because its implementation limit was exceeded. Instead, if the
>> required length is in this range, this method returns that required length.
>>
>> Separately, I'll work on retrofitting various call sites around the JDK to
>> use this method.
>
> Stuart Marks has updated the pull request incrementally with one additional
> commit since the last revision:
>
> fix typo, clarify asserts disabled, test prefGrowth==0
Marked as reviewed by martin (Reviewer).
test/jdk/jdk/internal/util/ArraysSupport/NewLength.java line 101:
> 99: fail("expected OutOfMemoryError, got normal return value of "
> + r);
> 100: } catch (OutOfMemoryError oome) {
> 101: // ok
Instead of an //ok comment, I like to give the exception a name that makes the
intent clear.
} catch (IllegalArgumentException success) {}
-------------
PR: https://git.openjdk.java.net/jdk/pull/1617
