RFR: 8251397: Add release fence to ClassValueMap constructor

[Severin Gehwolf]

On Mon, 14 Sep 2020 12:02:14 GMT, Severin Gehwolf <sgehwolf at openjdk.org> wrote:

>> You can add what you have as synopsis now via /summary and the bot.
>
> @galderz Now it's the other way round. Commit message the bot mentions
> [here](https://github.com/openjdk/jdk/pull/94#issuecomment-691478179) should be something like this:
> 8251397: NPE on ClassValue.ClassValueMap.cacheArray
> 
> Add release fence to ClassValueMap constructor.
> 
> * Release fence guarantees that cacheArray field will published
>   with a non-null value.
> * Without this fix, CacheValueMap.cacheArray can sometimes be
>    seen as null.
> 
> Reviewed-by: shade, psandoz
> 
> The first line can be achieved by force-pushing with the changed commit message. I know David said to not force push,
> but the review is done and no other way to achieve this except changing the bug synopsis which isn't great either. The
> latter lines can be added with /summary e.g.
> Add release fence to ClassValueMap constructor.
> 
> * Release fence guarantees that cacheArray field will published
>   with a non-null value.
> * Without this fix, CacheValueMap.cacheArray can sometimes be
>    seen as null.
> 
> The `Reviewed-by:` line comes from the reviewers.

Note that I've opened [SKARA-633](https://bugs.openjdk.java.net/browse/SKARA-633) for pre-population of the commit
message with an appropriate summary.

-------------

PR: https://git.openjdk.java.net/jdk/pull/94