variable.c: fix thread + fork errors in autoload

This is fairly non-intrusive bugfix to prevent children
from trying to reach into thread stacks of the parent.
I will probably reuse this idea and redo r62934, too
(same bug).

* vm_core.h (typedef struct rb_vm_struct): add fork_gen counter
* thread.c (rb_thread_atfork_internal): increment fork_gen
* variable.c (struct autoload_data_i): store fork_gen
* variable.c (check_autoload_data): remove (replaced with get_...)
* variable.c (get_autoload_data): check fork_gen when retrieving
* variable.c (check_autoload_required): use get_autoload_data
* variable.c (rb_autoloading_value): ditto
* variable.c (rb_autoload_p): ditto
* variable.c (current_autoload_data): ditto
* variable.c (autoload_reset): reset fork_gen, adjust indent
* variable.c (rb_autoload_load): set fork_gen when setting state
* test/ruby/test_autoload.rb (test_autoload_fork): new test
  [ruby-core:86410] [Bug #14634]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63210 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 26 insertions, 0 deletions

diff --git a/test/ruby/test_autoload.rb b/test/ruby/test_autoload.rb
index 0220f3e27d..3095052a81 100644
--- a/test/ruby/test_autoload.rb
+++ b/test/ruby/test_autoload.rb
@@ -285,6 +285,32 @@ p Foo::Bar
     end
   end
 
+  def test_autoload_fork
+    EnvUtil.default_warning do
+      Tempfile.create(['autoload', '.rb']) {|file|
+        file.puts 'sleep 0.3; class AutoloadTest; end'
+        file.close
+        add_autoload(file.path)
+        begin
+          thrs = []
+          3.times do
+            thrs << Thread.new { AutoloadTest; nil }
+            thrs << Thread.new { fork { AutoloadTest } }
+          end
+          thrs.each(&:join)
+          thrs.each do |th|
+            pid = th.value or next
+            _, status = Process.waitpid2(pid)
+            assert_predicate status, :success?
+          end
+        ensure
+          remove_autoload_constant
+          assert_nil $!, '[ruby-core:86410] [Bug #14634]'
+        end
+      }
+    end
+  end if Process.respond_to?(:fork)
+
   def add_autoload(path)
     (@autoload_paths ||= []) << path
     ::Object.class_eval {autoload(:AutoloadTest, path)}