On Mon, 19 Oct 2026 19:07:38 GMT, Srikanth Palutla <[email protected]> wrote:
>> Problem >> new PriorityQueue<>(List.of(new Object())) succeeds today when it should >> throw ClassCastException. initFromCollection relies on heapify() to surface >> incomparable elements, but heapify performs no comparisons on a singleton, >> so the lone element is never validated. Collections with two or more >> non-Comparable elements already throw. >> >> Fix >> In initFromCollection, when the collection holds exactly one element and no >> comparator is in play, self-compare the element before heapifying. This >> mirrors what TreeMap does for its first key (see JDK-5045147). Behavior with >> an explicit comparator is unchanged: non-Comparable elements are still >> accepted when a comparator is provided. >> >> Testing >> Added a copyConstructorSingleton regression test to AddNonComparable >> covering PriorityQueue(Collection) and PriorityQueue(Collection, Comparator) >> with a null comparator, plus the positive cases (Comparable singleton, >> explicit comparator). Verified the new test passes against the patched class >> and the existing queues() test still passes. >> >> >> Please let me know for further questions >> >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Srikanth Palutla has updated the pull request incrementally with one > additional commit since the last revision: > > Simplify singleton check per review: instanceof + explicit CCE @viktorklang-ora or @jaikiran - would you be able to review this and merge ? Thanks ------------- PR Comment: https://git.openjdk.org/jdk/pull/32966#issuecomment-6687662914
