Upgrade to Swift 5.2

DockProgress.podspec

@@ -8,6 +8,6 @@ Pod::Spec.new do |s|
 	s.authors = { 'Sindre Sorhus' => 'sindresorhus@gmail.com' }
 	s.source = { :git => 'https://github.com/sindresorhus/DockProgress.git', :tag => "v#{s.version}" }
 	s.source_files = 'Sources/**/*.swift'
-	s.swift_version = '5.1'
+	s.swift_version = '5.2'
 	s.platform = :macos, '10.12'
 end

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.1
+// swift-tools-version:5.2
 import PackageDescription
 
 let package = Package(

Sources/DockProgress/DockProgress.swift

@@ -12,11 +12,17 @@ public final class DockProgress {
 	public static weak var progressInstance: Progress? {
 		didSet {
 			guard let progressInstance = progressInstance else {
+				progressObserver = nil
+				finishedObserver = nil
+				resetProgress()
 				return
 			}
 
 			progressObserver = progressInstance.observe(\.fractionCompleted) { sender, _ in
-				guard !sender.isCancelled, !sender.isFinished else {
+				guard
+					!sender.isCancelled,
+					!sender.isFinished
+				else {
 					return
 				}
 
@@ -24,7 +30,10 @@ public final class DockProgress {
 			}
 
 			finishedObserver = progressInstance.observe(\.isFinished) { sender, _ in
-				guard !sender.isCancelled, sender.isFinished else {
+				guard
+					!sender.isCancelled,
+					sender.isFinished
+				else {
 					return
 				}
 

readme.md

@@ -9,8 +9,8 @@ This package is used in production by the [Gifski app](https://github.com/sindre
 ## Requirements
 
 - macOS 10.12+
-- Xcode 10.2+
+- Xcode 11.4+
-- Swift 5.1+
+- Swift 5.2+
 
 ## Install