[rwstauner]

replaces #93

[k0kubun]

Is the CI crash relevant to our backports?

[luke-gruber]

@k0kubun We've seen this before, I don't think it's an indication of a regression.

[k0kubun]

I see, I think it's safe to migrate our current version to this one then. I was more worried about whether it's something reproducible in ruby_4_0 alone or only in ruby-definitions, and are you saying you saw it on ruby/ruby?

[rwstauner]

There's a very similar crash that sometimes happens testing 4.0.7-pshopify1:
https://github.com/Shopify/ruby-definitions/actions/runs/39712449999/job/119606743588#step:7:278

So it might be something introduced by the non-official backports, or maybe those made it more likely, but sometimes CI passes fine:
https://github.com/Shopify/ruby-definitions/actions/runs/39876678354/job/120163881630

[rwstauner]

benchmarks are showing 4.0.9-pshopify1 as slower than 4.0.9 across various benchmarks (not always the same ones).

two failed CI benchmarks:

• https://github.com/Shopify/ruby-definitions/actions/runs/39987827743/attempts/2#summary-120568461925
• https://github.com/Shopify/ruby-definitions/actions/runs/39987827743/attempts/1#summary-120531568116

My local linux machine is showing similar results.

[rwstauner]

Benchmarking 4.0.7-pshopify2 to this 4.0.9-pshopify1 seems pretty similar

a: ruby 4.0.7 (2026-09-29 revision 92f8ccf5c9) +YJIT +PRISM [x86_64-linux]
b: ruby 4.0.9 (2026-10-24 revision 88b318ef73) +YJIT +PRISM [x86_64-linux]
ruby-bench: 5e3cbf67cf77849f018dde3793d3ef97292c6be0

default:
--------------  -------------  -------------  ---------  -----
bench                  a (ms)         b (ms)  b 1st itr    a/b
activerecord     122.7 ± 1.0%   121.4 ± 1.4%      1.015  1.011
chunky-png       466.7 ± 0.8%   463.5 ± 0.4%      0.991  1.007
erubi-rails      841.5 ± 0.3%   842.8 ± 0.4%      0.979  0.999
hexapdf         1550.7 ± 3.8%  1591.1 ± 2.5%      0.984  0.975
liquid-c          53.1 ± 1.8%    53.8 ± 1.8%      0.992  0.987
liquid-compile    44.4 ± 3.0%    45.3 ± 3.0%      0.993  0.982
liquid-il        196.2 ± 0.4%   193.3 ± 0.4%      1.008  1.015
liquid-render     73.8 ± 5.9%    74.2 ± 6.4%      0.985  0.995
lobsters         946.3 ± 2.3%   968.7 ± 2.5%      0.987  0.977
mail             110.0 ± 0.7%   111.1 ± 0.7%      1.013  0.990
psych-load      1571.5 ± 0.3%  1541.0 ± 0.7%      1.014  1.020
railsbench      1750.9 ± 0.4%  1776.1 ± 0.3%      0.976  0.986
rubocop          121.8 ± 9.3%   120.0 ± 8.8%      0.990  1.014
ruby-lsp         134.7 ± 1.9%   133.9 ± 2.1%      1.008  1.006
sequel            66.6 ± 1.1%    67.3 ± 1.2%      0.982  0.990
shipit          1362.1 ± 2.1%  1376.4 ± 3.6%      1.020  0.990
--------------  -------------  -------------  ---------  -----