(Hopefully) fixed some threading issues related to merging Futures.

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
  }