Concurrency Coordination Reports

Fiber Resume Coordination Report

Resume a fiber to read the checkpoint it reports and label the reached stage.

fiber resume `Fiber#resume` runs a fiber until its `Fiber.yield` and returns the yielded value, so resuming the fiber reads the checkpoint it reports for the selected stage while the fiber stays suspended and no background work keeps running.

Fiber Resume Coordination Report

checkpoint
fiber_resume_coordination_report.rb
Replay: real traced execution (multi-file project)
checkpoint = 1
labels = ["first", "second", "done"]
sequence = Fiber.new do
  Fiber.yield(labels.fetch(checkpoint - 1))
  "closed"
end

reached = sequence.resume
alive = sequence.alive?
status = reached

puts "checkpoint=#{checkpoint}"
puts "reached=#{reached}"
puts "alive=#{alive}"
puts "status=#{status}"

checkpoint = 2
labels = ["first", "second", "done"]
sequence = Fiber.new do
  Fiber.yield(labels.fetch(checkpoint - 1))
  "closed"
end

reached = sequence.resume
alive = sequence.alive?
status = reached

puts "checkpoint=#{checkpoint}"
puts "reached=#{reached}"
puts "alive=#{alive}"
puts "status=#{status}"

checkpoint = 3
labels = ["first", "second", "done"]
sequence = Fiber.new do
  Fiber.yield(labels.fetch(checkpoint - 1))
  "closed"
end

reached = sequence.resume
alive = sequence.alive?
status = reached

puts "checkpoint=#{checkpoint}"
puts "reached=#{reached}"
puts "alive=#{alive}"
puts "status=#{status}"

  1. checkpoint ← 1, labels ← ["first", "second", "done"], sequence ← ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩

    1checkpoint→ 1 = 1  #@checkpoint=2, 32labels→ ["first", "second", "done"] = ["first", "second", "done"]3sequence→ ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩ = Fiber.new do4  Fiber.yield(labels.fetch(checkpoint - 1))5  "closed"6end78reached = sequence⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩.resume9alive = sequence.alive?

  2. sequence ← ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (suspended)⟩

    8reached→ first = sequence→ ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (suspended)⟩.resume9alive→ true = sequence.alive?true10status→ first = reachedfirst1112puts "checkpoint=#{checkpoint1}"13puts "reached=#{reachedfirst}"14puts "alive=#{alivetrue}"15puts "status=#{statusfirst}"
    outputcheckpoint=1
reached=first
alive=true
status=first

  1. checkpoint ← 2, labels ← ["first", "second", "done"], sequence ← ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩

    1checkpoint→ 2 = 22labels→ ["first", "second", "done"] = ["first", "second", "done"]3sequence→ ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩ = Fiber.new do4  Fiber.yield(labels.fetch(checkpoint - 1))5  "closed"6end78reached = sequence⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩.resume9alive = sequence.alive?

  2. sequence ← ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (suspended)⟩

    8reached→ second = sequence→ ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (suspended)⟩.resume9alive→ true = sequence.alive?true10status→ second = reachedsecond1112puts "checkpoint=#{checkpoint2}"13puts "reached=#{reachedsecond}"14puts "alive=#{alivetrue}"15puts "status=#{statussecond}"
    outputcheckpoint=2
reached=second
alive=true
status=second

  1. checkpoint ← 3, labels ← ["first", "second", "done"], sequence ← ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩

    1checkpoint→ 3 = 32labels→ ["first", "second", "done"] = ["first", "second", "done"]3sequence→ ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩ = Fiber.new do4  Fiber.yield(labels.fetch(checkpoint - 1))5  "closed"6end78reached = sequence⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (created)⟩.resume9alive = sequence.alive?

  2. sequence ← ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (suspended)⟩

    8reached→ done = sequence→ ⟨Fiber A /tmp/execution/⟨tmp B⟩.rb:40 (suspended)⟩.resume9alive→ true = sequence.alive?true10status→ done = reacheddone1112puts "checkpoint=#{checkpoint3}"13puts "reached=#{reacheddone}"14puts "alive=#{alivetrue}"15puts "status=#{statusdone}"
    outputcheckpoint=3
reached=done
alive=true
status=done