thread_leak.rb

# Works fine
loop do
  before_gc = ObjectSpace.each_object(Thread).count
  GC.start
  after_gc  = ObjectSpace.each_object(Thread).to_a  # <-- note #to_a in loop

  $stdout.print "before_gc=#{before_gc} after_gc=#{after_gc.count}\n"

  sleep 1
end

# Also works fine
begin
  before_gc = ObjectSpace.each_object(Thread).count
  GC.start
  after_gc  = ObjectSpace.each_object(Thread).count  # <-- note #count in begin/while

  $stdout.print "before_gc=#{before_gc} after_gc=#{after_gc}\n"

  sleep 1
end while true

# LEAKS THREADS
begin
  before_gc = ObjectSpace.each_object(Thread).count
  GC.start
  after_gc  = ObjectSpace.each_object(Thread).to_a  # <-- note #to_a in begin/while

  $stdout.print "before_gc=#{before_gc} after_gc=#{after_gc.count}\n"

  sleep 1
end while true