Issue #4040 has been updated by ko1 (Koichi Sasada). Quote from devmeeting agenda https://bugs.ruby-lang.org/issues/19525:

The fix results in a minor performance decrease in microbenchmarks.

Could you show more details (results)? Do you have an analysis which line(s) makes slower? ---- I don't think this feature should be rejected. It is cool to support this feature (long splat can be accepted by rest argument). However, personally speaking I feel the proposed patch (https://github.com/ruby/ruby/pull/7522) is too complex for future maintenance comparing with the benefits from the patch. Now I have no time to review the patch closely and I couldn't confirm this patch has such issue. So I agree to merge it (and rewrite them if they can be more improved) because it is well tested. I think it is better to have benchmark measurements on some benchmarks, though. General comments: * Some code are duplicated so maybe they can be more shorter. * (optimization) It is not sure how the optimization target cases are there (optimizations for the minor cases can introduce issues such as i-cache miss, difficulty on future maintenance and so on). ---------------------------------------- Bug #4040: SystemStackError with Hash[*a] for Large _a_ https://bugs.ruby-lang.org/issues/4040#change-102785 * Author: runpaint (Run Paint Run Run) * Status: Open * Priority: Normal * Assignee: ko1 (Koichi Sasada) * ruby -v: ruby 1.9.3dev (2010-11-09 trunk 29737) [x86_64-linux] * Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN ---------------------------------------- =begin I've been hesitating over whether to file a ticket about this, so please feel free to close if I've made the wrong choice. I often use Hash[*array.flatten] in IRB to convert arrays of arrays into hashes. Today I noticed that if the array is big enough, this would raise a SystemStackError. Puzzled, I looked deeper. I assumed I was hitting the maximum number of arguments a method's argc can hold, but realised that the minimum size of the array needed to trigger this exception differed depending on whether I used IRB or not. So, presumably this is indeed exhausting the stack... In IRB, the following is the minimal reproduction of this problem: Hash[*130648.times.map{ 1 }]; true I haven't looked for the minimum value needed with `ruby -e`, but the following reproduces: ruby -e 'Hash[*1380888.times.map{ 1 }]' I suppose this isn't technically a bug, but maybe it offers another argument for either #666 or an extension of #3131. =end -- https://bugs.ruby-lang.org/