From 7f7dbef47d0fa4847e8200cae9bf7881d8612aff Mon Sep 17 00:00:00 2001
From: Adam Fowler <adamfowler71@gmail.com>
Date: Wed, 24 Jan 2024 13:19:33 +0000
Subject: [PATCH] Ensure we are running on EventLoop after AsyncMiddleware
 (#357)

---
 .../AsyncAwaitSupport/AsyncMiddleware.swift   |  8 +++++--
 Tests/HummingbirdTests/AsyncAwaitTests.swift  | 24 +++++++++++++++++++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/Sources/Hummingbird/AsyncAwaitSupport/AsyncMiddleware.swift b/Sources/Hummingbird/AsyncAwaitSupport/AsyncMiddleware.swift
index 3a6f9f302..8e1b3b3c7 100644
--- a/Sources/Hummingbird/AsyncAwaitSupport/AsyncMiddleware.swift
+++ b/Sources/Hummingbird/AsyncAwaitSupport/AsyncMiddleware.swift
@@ -42,10 +42,14 @@ struct HBPropagateServiceContextResponder: HBResponder {
     func respond(to request: HBRequest) -> EventLoopFuture<HBResponse> {
         if let serviceContext = ServiceContext.$current.get() {
             return request.withServiceContext(serviceContext) { request in
-                self.responder.respond(to: request)
+                return request.eventLoop.flatSubmit {
+                    self.responder.respond(to: request)
+                }
             }
         } else {
-            return self.responder.respond(to: request)
+            return request.eventLoop.flatSubmit {
+                self.responder.respond(to: request)
+            }
         }
     }
 }
diff --git a/Tests/HummingbirdTests/AsyncAwaitTests.swift b/Tests/HummingbirdTests/AsyncAwaitTests.swift
index ee8e126ac..d3ded28f8 100644
--- a/Tests/HummingbirdTests/AsyncAwaitTests.swift
+++ b/Tests/HummingbirdTests/AsyncAwaitTests.swift
@@ -228,4 +228,28 @@ final class AsyncAwaitTests: XCTestCase {
             XCTAssertEqual(String(buffer: body), "abcdefghijklmnopqrstuvwxyz")
         }
     }
+
+    func testAfterAsyncMiddleware() throws {
+        struct EmptyAsyncMiddleware: HBAsyncMiddleware {
+            func apply(to request: HBRequest, next: HBResponder) async throws -> HBResponse {
+                return try await next.respond(to: request)
+            }
+        }
+        struct TestOnEventLoopMiddleware: HBMiddleware {
+            func apply(to request: HBRequest, next: HBResponder) -> EventLoopFuture<HBResponse> {
+                request.eventLoop.preconditionInEventLoop()
+                return next.respond(to: request)
+            }
+        }
+        let app = HBApplication(testing: .asyncTest)
+        app.middleware.add(EmptyAsyncMiddleware())
+        app.middleware.add(TestOnEventLoopMiddleware())
+        app.router.get { _ in HTTPResponseStatus.ok }
+
+        try app.XCTStart()
+        defer { app.XCTStop() }
+        try app.XCTExecute(uri: "/", method: .GET) { response in
+            XCTAssertEqual(response.status, .ok)
+        }
+    }
 }