Issue #19439 has been updated by byroot (Jean Boussier). Ah! the explanation is quite funny. So the ivars are loaded fine, however, since the goal is to store the encoding, and that the encoding isn't on the regexp itself, but on the `regexp#source` which is a string, the ivars are assigned on that internal, inacessible string. ```ruby require 'objspace' ObjectSpace.trace_object_allocations_start GC.start gen = GC.count r = Regexp.new("a".b) r.instance_variable_set(:@ivar, []) r2 = Marshal.load(Marshal.dump(r)) puts ObjectSpace.dump_all(output: :string, shapes: false, since: gen) puts '-' * 40 puts ObjectSpace.dump(r2) ``` Filtered output: ``` {"address":"0x10323fd58", "type":"REGEXP", "shape_id":0, "slot_size":40, "class":"0x102fd2a98", "references":["0x10323fdf8"], "file":"<internal:marshal>", "line":35, "method":"load", "generation":6, "memsize":500, "flags":{"wb_protected":true}} {"address":"0x10323fdf8", "type":"STRING", "shape_id":237, "slot_size":40, "class":"0x102fded98", "frozen":true, "embedded":true, "bytesize":1, "value":"a", "encoding":"US-ASCII", "coderange":"unknown", "references":["0x10323fd80"], "file":"<internal:marshal>", "line":35, "method":"load", "generation":6, "memsize":56, "flags":{"wb_protected":true}} {"address":"0x10323fd80", "type":"ARRAY", "shape_id":0, "slot_size":40, "class":"0x102fd33f8", "length":0, "embedded":true, "file":"<internal:marshal>", "line":35, "method":"load", "generation":6, "memsize":40, "flags":{"wb_protected":true}} ---------------------------------------- {"address":"0x10323fd58", "type":"REGEXP", "shape_id":0, "slot_size":40, "class":"0x102fd2a98", "references":["0x10323fdf8"], "file":"<internal:marshal>", "line":35, "method":"load", "generation":6, "memsize":500, "flags":{"wb_protected":true}} ``` If you follow the references you see `Regexp -> String -> Array(length: 1)`. I think this may be fixable, but the fix may be dirty. ---------------------------------------- Bug #19439: Marshal.load doesn't load Regexp instance variables https://bugs.ruby-lang.org/issues/19439#change-101891 * Author: andrykonchin (Andrew Konchin) * Status: Open * Priority: Normal * ruby -v: 3.1.3 * Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN ---------------------------------------- Hello, I've noticed this strange behaviour: ```ruby source_object = Regexp.new("a") source_object.instance_variable_set(:@foo, :bar) regexp = Marshal.load(Marshal.dump(source_object)) regexp.instance_variables # => [] ``` I would expect instance variables to be loaded -- https://bugs.ruby-lang.org/