[Bug #21989] Fix FiberError init order to precede all possible usage

The `FiberError` class can be used in `fiber_pool_initialize` through
`fiber_pool_expand` but `FiberError` was defined after
`fiber_pool_initialize` in `Init_Cont`. This commit moves the definition
of `FiberError` before `fiber_pool_initialize` to ensure that
`FiberError` is defined before any possible usage.

1 files changed, 2 insertions, 1 deletions

diff --git a/cont.c b/cont.c
index c44d233a9f..6bb61e5ee8 100644
--- a/cont.c
+++ b/cont.c
@@ -3651,6 +3651,8 @@ Init_Cont(void)
 #endif
     SET_MACHINE_STACK_END(&th->ec->machine.stack_end);
 
+    rb_eFiberError = rb_define_class("FiberError", rb_eStandardError);
+
     size_t minimum_count = shared_fiber_pool_minimum_count();
     size_t maximum_count = shared_fiber_pool_maximum_count();
     fiber_pool_initialize(&shared_fiber_pool, stack_size, minimum_count, maximum_count, vm_stack_size);
@@ -3675,7 +3677,6 @@ Init_Cont(void)
 
     rb_cFiber = rb_define_class("Fiber", rb_cObject);
     rb_define_alloc_func(rb_cFiber, fiber_alloc);
-    rb_eFiberError = rb_define_class("FiberError", rb_eStandardError);
     rb_define_singleton_method(rb_cFiber, "yield", rb_fiber_s_yield, -1);
     rb_define_singleton_method(rb_cFiber, "current", rb_fiber_s_current, 0);
     rb_define_singleton_method(rb_cFiber, "blocking", rb_fiber_blocking, 0);