On Thu, 5 Jan 2023 01:02:11 GMT, Sergey Bylokhov <s...@openjdk.org> wrote:
>> There's no regression test. However, with the current code (prior to this >> change) a call to `Set.of(zeroLengthArray)` returns the same instance as >> `Set.of()`, so it's difficult to write a simple functional test for this >> change. The test would have to assert that "no HashSet is allocated along >> this code path" which is much harder to test and frankly probably isn't >> worth it. So, please add one of the `noreg-*` labels to the bug to indicate >> the rationale for omitting a regression test. >> >> https://openjdk.org/guide/#jbs-label-dictionary >> >> I'd probably add the `Map.copyOf` change to this PR to avoid some >> bug/PR/review overhead. Thanks for mentioning this @shipilev. > >> so it's difficult to write a simple functional test for this change. > > It is possible to track that for some "custom" and empty collection the only > method will be called is `isEmpty` and nothing else. Not sure how it is > useful or not. @mrserb @stuart-marks I've pushed two additional commits which adds the isEmpty-check for Map and List as well, although the improvement there should be smaller, especially for Lists. ------------- PR: https://git.openjdk.org/jdk/pull/11847
