module Support
Definitions
def self.fiber_scheduler_v1?
To be removed on 31 Mar 2025.
Implementation
def self.fiber_scheduler_v1?
IO.const_defined?(:Buffer)
end
def self.fiber_scheduler_v2?
To be removed on 31 Mar 2026.
Implementation
def self.fiber_scheduler_v2?
# Some interface changes were back-ported incorrectly:
# https://github.com/ruby/ruby/pull/10778
# Specifically "Improvements to IO::Buffer read/write/pread/pwrite."
# Missing correct size calculation.
return false if RUBY_VERSION >= "3.2.5"
IO.const_defined?(:Buffer) and Fiber.respond_to?(:blocking) and IO::Buffer.instance_method(:read).arity == -1
end
def self.fiber_scheduler_v3?
To become the default 31 Mar 2026.
Implementation
def self.fiber_scheduler_v3?
if fiber_scheduler_v2?
return true if RUBY_VERSION >= "3.3"
# Feature detection if required:
begin
IO::Buffer.new.slice(0, 0).write(STDOUT)
return true
rescue
return false
end
end
end