revert MRB_FIBER_RESUMED as MRB_FIBER_RESUMING to fix recurive resume

include/mruby.h

@@ -70,6 +70,7 @@ typedef struct {
 enum mrb_fiber_state {
   MRB_FIBER_CREATED = 0,
   MRB_FIBER_RUNNING,
+  MRB_FIBER_RESUMING,
   MRB_FIBER_SUSPENDED,
   MRB_FIBER_TERMINATED,
 };

mrbgems/mruby-fiber/src/fiber.c

@@ -164,13 +164,14 @@ fiber_resume(mrb_state *mrb, mrb_value self)
       mrb_raise(mrb, E_ARGUMENT_ERROR, "can't cross C function boundary");
     }
   }
-  if (c->status == MRB_FIBER_RUNNING || (mrb->c->prev && mrb->c->prev != mrb->root_c)) {
+  if (c->status == MRB_FIBER_RUNNING || c->status == MRB_FIBER_RESUMING) {
     mrb_raise(mrb, E_RUNTIME_ERROR, "double resume");
   }
   if (c->status == MRB_FIBER_TERMINATED) {
     mrb_raise(mrb, E_RUNTIME_ERROR, "resuming dead fiber");
   }
   mrb_get_args(mrb, "*", &a, &len);
+  mrb->c->status = MRB_FIBER_RESUMING;
   if (c->status == MRB_FIBER_CREATED) {
     mrb_value *b = c->stack+1;
     mrb_value *e = b + len;
@@ -183,7 +184,6 @@ fiber_resume(mrb_state *mrb, mrb_value self)
     if (c->prev->fib) 
       mrb_field_write_barrier(mrb, (struct RBasic*)c->fib, (struct RBasic*)c->prev->fib);
     mrb_write_barrier(mrb, (struct RBasic*)c->fib);
-    mrb->c->status = MRB_FIBER_SUSPENDED;
     c->status = MRB_FIBER_RUNNING;
     mrb->c = c;
 
@@ -195,7 +195,6 @@ fiber_resume(mrb_state *mrb, mrb_value self)
   if (c->prev->fib) 
     mrb_field_write_barrier(mrb, (struct RBasic*)c->fib, (struct RBasic*)c->prev->fib);
   mrb_write_barrier(mrb, (struct RBasic*)c->fib);
-  mrb->c->status = MRB_FIBER_SUSPENDED;
   c->status = MRB_FIBER_RUNNING;
   mrb->c = c;
   return fiber_result(mrb, a, len);

mrbgems/mruby-fiber/test/fiber.rb

@@ -96,8 +96,12 @@ assert('Recursive resume of Fiber') do
     f1.resume
     Fiber.yield 0
   }
-  assert_equal 0, f2.resume
+  f3 = Fiber.new {
+    f2.resume
+  }
+  assert_equal 0, f3.resume
   f2.resume
   assert_false f1.alive?
   assert_false f2.alive?
+  assert_false f3.alive?
 end