Fiber#raise recursively raises on nested resuming_fiber. (#10482)

* Improve consistency of `Fiber.current.raise`.

cont.c

@@ -3227,7 +3227,13 @@ rb_fiber_s_yield(int argc, VALUE *argv, VALUE klass)
 static VALUE
 fiber_raise(rb_fiber_t *fiber, VALUE exception)
 {
-    if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
+    if (fiber == fiber_current()) {
+        rb_exc_raise(exception);
+    }
+    else if (fiber->resuming_fiber) {
+        return fiber_raise(fiber->resuming_fiber, exception);
+    }
+    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
         return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
     }
     else {

spec/ruby/core/fiber/raise_spec.rb

@@ -91,6 +91,40 @@ describe "Fiber#raise" do
 
     fiber_two.resume.should == [:yield_one, :rescued]
   end
+
+  ruby_version_is "3.4" do
+    it "raises on the resumed fiber" do
+      root_fiber = Fiber.current
+      f1 = Fiber.new { root_fiber.transfer }
+      f2 = Fiber.new { f1.resume }
+      f2.transfer
+
+      -> do
+        f2.raise(RuntimeError, "Expected error")
+      end.should raise_error(RuntimeError, "Expected error")
+    end
+
+    it "raises on itself" do
+      -> do
+        Fiber.current.raise(RuntimeError, "Expected error")
+      end.should raise_error(RuntimeError, "Expected error")
+    end
+
+    it "should raise on parent fiber" do
+      f2 = nil
+      f1 = Fiber.new do
+        # This is equivalent to Kernel#raise:
+        f2.raise(RuntimeError, "Expected error")
+      end
+      f2 = Fiber.new do
+        f1.resume
+      end
+
+      -> do
+        f2.resume
+      end.should raise_error(RuntimeError, "Expected error")
+    end
+  end
 end