Merge pull request #1 from jakehawken/jake/immediateExecutionBugFix

Immediate execution bug fix.

Sources/Propagate/PromiseAndFuture/Future.swift

@@ -76,11 +76,14 @@ public class Future<T, E: Error> {
  - returns: The future iself, as a `@discardableResult` to allow for chaining of callback methods.
  */
  @discardableResult public func onSuccess(onQueue overrideQueue: DispatchQueue? = nil, _ callback: @escaping SuccessBlock) -> Future<T, E> {
+ let queueForCallback = overrideQueue ?? callbackQueue
  if let value = value { //If the future has already been resolved with a value. Call the block immediately.
- callback(value)
+ queueForCallback.async {
+ callback(value)
+ }
  }
  else if successCallbackPair == nil {
- successCallbackPair = (callback, overrideQueue ?? callbackQueue)
+ successCallbackPair = (callback, queueForCallback)
  }
  else if let child = childFuture {
  child.onSuccess(onQueue: overrideQueue, callback)
@@ -99,11 +102,14 @@ public class Future<T, E: Error> {
  - returns: The future iself, as a `@discardableResult` to allow for chaining of callback methods.
  */
  @discardableResult public func onFailure(onQueue overrideQueue: DispatchQueue? = nil, _ callback: @escaping ErrorBlock) -> Future<T, E> {
+ let queueForCallback = overrideQueue ?? callbackQueue
  if let error = self.error { //If the future has already been rejected with an error. Call the block immediately.
- callback(error)
+ queueForCallback.async {
+ callback(error)
+ }
  }
  else if self.errorCallbackPair == nil {
- self.errorCallbackPair = (callback, overrideQueue ?? callbackQueue)
+ self.errorCallbackPair = (callback, queueForCallback)
  }
  else if let child = childFuture {
  child.onFailure(onQueue: overrideQueue, callback)
@@ -122,11 +128,14 @@ public class Future<T, E: Error> {
  - returns: The future iself, as a `@discardableResult` to allow for chaining of callback methods.
  */
  @discardableResult public func finally(onQueue overrideQueue: DispatchQueue? = nil, _ callback: @escaping (Result<T, E>) -> Void) -> Future<T, E> {
+ let queueForCallback = overrideQueue ?? callbackQueue
  if let result = result {
- callback(result)
+ queueForCallback.async {
+ callback(result)
+ }
  }
  else if finallyCallbackPair == nil {
- finallyCallbackPair = (callback, overrideQueue ?? callbackQueue)
+ finallyCallbackPair = (callback, queueForCallback)
  }
  else if let child = childFuture {
  child.finally(onQueue: overrideQueue, callback)