From bfd9b398bbb6e9380d2f3a97dc4a76a7092d4b7f Mon Sep 17 00:00:00 2001
From: Tobias Haeberle <tobias.haeberle@holidu.com>
Date: Wed, 26 Jun 2019 23:37:56 +0200
Subject: [PATCH] Make sure that event loop of task is the same as event loop
 of channel

---
 Sources/AsyncHTTPClient/HTTPClient.swift      |  2 +-
 Sources/AsyncHTTPClient/HTTPHandler.swift     |  1 +
 .../HTTPClientTests+XCTest.swift              |  1 +
 .../HTTPClientTests.swift                     | 19 +++++++++++++++++++
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Sources/AsyncHTTPClient/HTTPClient.swift b/Sources/AsyncHTTPClient/HTTPClient.swift
index 4b3bab7ca..df7b4ea4c 100644
--- a/Sources/AsyncHTTPClient/HTTPClient.swift
+++ b/Sources/AsyncHTTPClient/HTTPClient.swift
@@ -123,7 +123,7 @@ public class HTTPClient {
 
         let task = Task<T.Response>(eventLoop: eventLoop)
 
-        var bootstrap = ClientBootstrap(group: self.eventLoopGroup)
+        var bootstrap = ClientBootstrap(group: eventLoop)
             .channelOption(ChannelOptions.socket(SocketOptionLevel(IPPROTO_TCP), TCP_NODELAY), value: 1)
             .channelInitializer { channel in
                 let encoder = HTTPRequestEncoder()
diff --git a/Sources/AsyncHTTPClient/HTTPHandler.swift b/Sources/AsyncHTTPClient/HTTPHandler.swift
index 9cfb7c970..862c7a371 100644
--- a/Sources/AsyncHTTPClient/HTTPHandler.swift
+++ b/Sources/AsyncHTTPClient/HTTPHandler.swift
@@ -271,6 +271,7 @@ extension HTTPClient {
         }
 
         func setChannel(_ channel: Channel) -> Channel {
+            precondition(self.eventLoop === channel.eventLoop, "Channel must use same event loop as this task.")
             return self.lock.withLock {
                 self.channel = channel
                 return channel
diff --git a/Tests/AsyncHTTPClientTests/HTTPClientTests+XCTest.swift b/Tests/AsyncHTTPClientTests/HTTPClientTests+XCTest.swift
index 644a9b50c..5b46c82c8 100644
--- a/Tests/AsyncHTTPClientTests/HTTPClientTests+XCTest.swift
+++ b/Tests/AsyncHTTPClientTests/HTTPClientTests+XCTest.swift
@@ -27,6 +27,7 @@ extension HTTPClientTests {
         return [
             ("testRequestURI", testRequestURI),
             ("testGet", testGet),
+            ("testGetWithSharedEventLoopGroup", testGetWithSharedEventLoopGroup),
             ("testPost", testPost),
             ("testGetHttps", testGetHttps),
             ("testPostHttps", testPostHttps),
diff --git a/Tests/AsyncHTTPClientTests/HTTPClientTests.swift b/Tests/AsyncHTTPClientTests/HTTPClientTests.swift
index 506968528..d6a6640de 100644
--- a/Tests/AsyncHTTPClientTests/HTTPClientTests.swift
+++ b/Tests/AsyncHTTPClientTests/HTTPClientTests.swift
@@ -44,6 +44,25 @@ class HTTPClientTests: XCTestCase {
         let response = try httpClient.get(url: "http://localhost:\(httpBin.port)/get").wait()
         XCTAssertEqual(.ok, response.status)
     }
+    
+    func testGetWithSharedEventLoopGroup() throws {
+        let httpBin = HttpBin()
+        let elg = MultiThreadedEventLoopGroup(numberOfThreads: 8)
+        let httpClient = HTTPClient(eventLoopGroupProvider: .shared(elg))
+        defer {
+            try! elg.syncShutdownGracefully()
+            httpBin.shutdown()
+        }
+        
+        let delegate = TestHTTPDelegate()
+        let request = try HTTPClient.Request(url: "http://localhost:\(httpBin.port)/events/10/1")
+        let task = httpClient.execute(request: request, delegate: delegate)
+        let expectedEventLoop = task.eventLoop
+        task.futureResult.whenComplete { (_) in
+            XCTAssertTrue(expectedEventLoop.inEventLoop)
+        }
+        try task.wait()
+    }
 
     func testPost() throws {
         let httpBin = HttpBin()