Issue #20226 has been updated by ufuk (Ufuk Kayserilioglu). `Enumerable#sort_by` was also documented to not be stable in 3.2 (and previous versions): https://ruby-doc.org/3.2.3/Enumerable.html#method-i-sort_by What might have changed (this is a layman's guess since I don't know the internals of Ruby sorting that well) is which sort routine Ruby uses from the OS/libc by default, which might change the behaviour of the resulting sort. Since Ruby provides no guarantees of stable sorting, this is not a regression, despite what specific platform sort routines might provide. ---------------------------------------- Bug #20226: Inconsistent Sort results on 3.3.0 compared to previous versions https://bugs.ruby-lang.org/issues/20226#change-106521 * Author: omerby (Omer Ben Yosef) * Status: Open * Priority: Normal * ruby -v: 3.3.0 * Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN ---------------------------------------- Try this code block: ``` [-0.9, -0.88, -0.85, -0.83, -0.81, -0.79, -0.77, -0.75, -0.73, -0.71, -0.69, -0.67, -0.65, -0.63, -0.6, -0.58, -0.56, -0.54, -0.52, -0.5, -0.48, -0.46, -0.44, -0.42, -0.4, -0.38, -0.35, -0.33, -0.31, -0.29, -0.27, -0.25, -0.23, -0.21, -0.19, -0.17, -0.15, -0.13, -0.1, -0.08, -0.06, -0.04, -0.02, 0.0, 0.02, 0.0, 0.02].sort_by(&:abs) ``` The end result should be the numbers absolute sorted, look at the last 5 numbers of this, the end result of them should be `[0.0, 0.0, -0.02, 0.02, 0.02...]` maintaining the original order, and this behavior is what we see on ruby 3.2.0, however on ruby 3.3.0 the end result will be `[0.0, 0.0, 0.02, 0.02, -0.02...]` This is also inconsistent, as `[-0.02, 0.0, 0.02, 0.0, 0.02].sort_by(&:abs)` will actually provide the expected result. Again, the main issue for us is the difference between 3.3.0 and previous versions of ruby. -- https://bugs.ruby-lang.org/