Issue #19150 has been updated by Eregon (Benoit Daloze). Status changed from Open to Closed Backport changed from 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN to 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED Done in https://github.com/ruby/ruby/commit/03dd37775afb40eef392ae2920d728235af302c8, also needed changes in specs: https://github.com/ruby/spec/commit/9d69b95a7bbac3d89e7218a98bd50ecf173d9c6f ---------------------------------------- Bug #19150: pack/unpack silently ignores unknown directives https://bugs.ruby-lang.org/issues/19150#change-101046 * Author: Eregon (Benoit Daloze) * Status: Closed * Priority: Normal * Target version: 3.3 * Backport: 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONTNEED ---------------------------------------- But I believe it should be an error instead. Typically when a parser sees a syntax error it should fail not continue silently. For instance `[1].pack('<L')` succeeds and only emits a warning if `$VERBOSE` is true. This behavior caused confusion in https://github.com/oracle/truffleruby/issues/2791 I think it should fail with an `ArgumentError` instead. Extracted from https://bugs.ruby-lang.org/issues/19108#note-3 -- https://bugs.ruby-lang.org/