RFR: 8352969: G1: Improve testability of optional collections [v10]

[Guanqiang Han]

On Thu, 11 Sep 2025 11:19:51 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Guanqiang Han has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update TestOptionalRegionGC.java
>>   
>>   Correct the formatting errors
>
> src/hotspot/share/gc/g1/g1CollectionSet.cpp line 417:
> 
>> 415:   G1CSetCandidateGroupList* from_marking_groups = &candidates()->from_marking_groups();
>> 416: 
>> 417: #ifdef ASSERT
> 
> I'd suggest removing `#ifdef ASSERT`; the compiler should be able to remove unreachable code in an optimized build.

Hi @albertnetymk , thanks for the suggestion! While the compiler may indeed optimize away unreachable branches, 
keeping the `#ifdef ASSERT` here makes it clear that this block is intended for development/debugging 
and also helps with readability and maintainability for future reviewers. 
I’m happy to adjust if there’s a preferred convention you’d like me to follow.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26880#discussion_r2340608619