Issue #20868 has been updated by k0kubun (Takashi Kokubun). Backport changed from 3.1: WONTFIX, 3.2: DONE, 3.3: REQUIRED to 3.1: WONTFIX, 3.2: DONE, 3.3: DONE ruby_3_3 commit:42f043c1893b320b9d2a38ec3b1065dee71ce863 merged revision(s) commit:56ecc243e230e8e99761ec0ffc5116601f094bb0. ---------------------------------------- Bug #20868: Method#hash changes after compaction https://bugs.ruby-lang.org/issues/20868#change-111499 * Author: peterzhu2118 (Peter Zhu) * Status: Closed * Backport: 3.1: WONTFIX, 3.2: DONE, 3.3: DONE ---------------------------------------- Fix: https://github.com/ruby/ruby/pull/12004 The hash value of a Method may change after a compaction but must remain constant because otherwise it may not work as the key in a hash table. For example: ```ruby def a; end # Need this method here because otherwise the iseq may be on the C stack # which would get pinned and not move during compaction def get_hash method(:a).hash end puts get_hash # => 2993401401091578131 GC.verify_compaction_references(expand_heap: true, toward: :empty) puts get_hash # => -2162775864511574135 ``` -- https://bugs.ruby-lang.org/