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ruby--ruby/spec/ruby/library/fiber/transfer_spec.rb
Jeremy Evans fa8ac91e95
Fix Fiber#transfer
Fiber#transfer previously made it impossible to resume the fiber
if it was transferred to (no resuming the target of Fiber#transfer).
However, the documentation specifies that you cannot resume a fiber
that has transferred to another fiber (no resuming the source of
Fiber#transfer), unless control is transferred back.

Fix the code by setting the transferred flag on the current/source
fiber, and unsetting the transferred flag on the target fiber.

Fixes [Bug #9664]
Fixes [Bug #12555]
2019-10-21 16:54:58 -07:00

95 lines
2.9 KiB
Ruby

require_relative '../../spec_helper'
require_relative '../../shared/fiber/resume'
require 'fiber'
describe "Fiber#transfer" do
it_behaves_like :fiber_resume, :transfer
end
describe "Fiber#transfer" do
it "transfers control from one Fiber to another when called from a Fiber" do
fiber1 = Fiber.new { :fiber1 }
fiber2 = Fiber.new { fiber1.transfer; :fiber2 }
fiber2.resume.should == :fiber1
end
it "returns to the root Fiber when finished" do
f1 = Fiber.new { :fiber_1 }
f2 = Fiber.new { f1.transfer; :fiber_2 }
f2.transfer.should == :fiber_1
f2.transfer.should == :fiber_2
end
it "can be invoked from the same Fiber it transfers control to" do
states = []
fiber = Fiber.new { states << :start; fiber.transfer; states << :end }
fiber.transfer
states.should == [:start, :end]
states = []
fiber = Fiber.new { states << :start; fiber.transfer; states << :end }
fiber.resume
states.should == [:start, :end]
end
it "can transfer control to a Fiber that has transferred to another Fiber" do
states = []
fiber1 = Fiber.new { states << :fiber1 }
fiber2 = Fiber.new { states << :fiber2_start; fiber1.transfer; states << :fiber2_end}
fiber2.resume.should == [:fiber2_start, :fiber1]
fiber2.transfer.should == [:fiber2_start, :fiber1, :fiber2_end]
end
ruby_version_is ''...'2.7' do
it "raises a FiberError when transferring to a Fiber which resumes itself" do
fiber = Fiber.new { fiber.resume }
-> { fiber.transfer }.should raise_error(FiberError)
end
end
ruby_version_is '2.7' do
it "allows transferring to a Fiber which resumes itself" do
fiber = Fiber.new { fiber.resume 1 }
fiber.transfer.should == 1
end
end
it "works if Fibers in different Threads each transfer to a Fiber in the same Thread" do
# This catches a bug where Fibers are running on a thread-pool
# and Fibers from a different Ruby Thread reuse the same native thread.
# Caching the Ruby Thread based on the native thread is not correct in that case,
# and the check for "fiber called across threads" in Fiber#transfer
# might be incorrect based on that.
2.times do
Thread.new do
io_fiber = Fiber.new do |calling_fiber|
calling_fiber.transfer
end
io_fiber.transfer(Fiber.current)
value = Object.new
io_fiber.transfer(value).should equal value
end.join
end
end
it "transfers control between a non-main thread's root fiber to a child fiber and back again" do
states = []
thread = Thread.new do
f1 = Fiber.new do |f0|
states << 0
value2 = f0.transfer(1)
states << value2
3
end
value1 = f1.transfer(Fiber.current)
states << value1
value3 = f1.transfer(2)
states << value3
end
thread.join
states.should == [0, 1, 2, 3]
end
end