RFR: 8316879: RegionMatches1Tests fails if CompactStrings are disabled after JDK-8302163 [v3]

[Roger Riggs]

On Tue, 26 Sep 2023 14:06:56 GMT, Aleksei Voitylov <avoitylov at openjdk.org> wrote:

>> test java.lang.String.RegionMatches1Tests fails on all platforms with -XX:-CompactStrings option and on ARM32 where Compact Strings is disabled by default. The fix is to return true immediately if len is negative, since for negative length this condition will never be satisfied.
>> 
>> Testing: JCK, JTREG passed with the fix with -XX:-CompactStrings on x86_64 and on ARM32.
>
> Aleksei Voitylov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update src/java.base/share/classes/java/lang/String.java
>   
>   Co-authored-by: Raffaello Giulietti <raffaello.giulietti at oracle.com>

src/java.base/share/classes/java/lang/String.java line 2162:

> 2160:         if (len < 0) {
> 2161:            return true;
> 2162:         }

Isn't it also true that the regions trivial match if len == 0?

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PR Review Comment: https://git.openjdk.org/jdk/pull/15906#discussion_r1337310557