From efc31058d30dca0bd839ca0d2bad582b1c42d5b8 Mon Sep 17 00:00:00 2001
From: Jake Hawken <jacobdhawken@gmail.com>
Date: Sun, 10 Jul 2022 15:30:20 -0700
Subject: [PATCH] (Hopefully) fixed some threading issues related to merging
 Futures.

---
 .../PromiseAndFuture/Future+Combine.swift     | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/Sources/Propagate/PromiseAndFuture/Future+Combine.swift b/Sources/Propagate/PromiseAndFuture/Future+Combine.swift
index ee26864..a11f77a 100644
--- a/Sources/Propagate/PromiseAndFuture/Future+Combine.swift
+++ b/Sources/Propagate/PromiseAndFuture/Future+Combine.swift
@@ -16,18 +16,20 @@ public extension Future {
     static func merge(_ futures: [Future<T, E>]) -> Future<[T], E> {
         let promise = Promise<[T], E>()
         
-        futures.forEach {
-            $0.finally { (_) in
-                promise.future.lockQueue.sync {
-                    let results = futures.compactMap { $0.result }
-                    let failures = results.compactMap { $0.failure }
-                    if let firstError = failures.first {
-                        promise.reject(firstError)
-                    }
+        futures.forEach { future in
+            future.finally { (_) in
+                promise.future.lockQueue.async {
                     guard promise.future.isComplete == false else {
                         return
                     }
-                    let successValues = results.compactMap { $0.success }
+                    
+                    if let errorFuture = futures.first(where: { $0.failed }),
+                       let error = errorFuture.error {
+                        promise.reject(error)
+                        return
+                    }
+                    
+                    let successValues = futures.compactMap(\.value)
                     guard successValues.count == futures.count else {
                         return
                     }