cont.c: set th->root_fiber to current fiber at fork

Otherwise, th->root_fiber can point to an invalid Fiber,
because Fibers do not live across fork.  So consider
whatever Fiber is running the root fiber.

[ruby-core:88723] [Bug #15041]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64589 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 5 insertions, 1 deletions

diff --git a/test/ruby/test_fiber.rb b/test/ruby/test_fiber.rb
index ef7790b53c..c835246fda 100644
--- a/test/ruby/test_fiber.rb
+++ b/test/ruby/test_fiber.rb
@@ -269,7 +269,11 @@ class TestFiber < Test::Unit::TestCase
     end
     bug5700 = '[ruby-core:41456]'
     assert_nothing_raised(bug5700) do
-      Fiber.new{ pid = fork {} }.resume
+      Fiber.new do
+        pid = fork do
+          Fiber.new {}.transfer
+        end
+      end.resume
     end
     pid, status = Process.waitpid2(pid)
     assert_equal(0, status.exitstatus, bug5700)