Remove the need to type-erase publisher to render the workflow view

Author: soorinpark

Diff for: Development.podspec

@@ -13,7 +13,6 @@ Pod::Spec.new do |s|
   s.dependency 'WorkflowUI'
   s.dependency 'WorkflowReactiveSwift'
   s.dependency 'WorkflowRxSwift'
-  # s.dependency 'WorkflowCombine' # TODO: Disabled because app specs cannot increase the deployment target of the root
   s.source_files = 'Samples/Dummy.swift'
 
   s.subspec 'Dummy' do |ss|
@@ -142,25 +141,4 @@ Pod::Spec.new do |s|
     test_spec.dependency 'WorkflowTesting'
     test_spec.dependency 'WorkflowRxSwiftTesting'
   end
-
-  # TODO: Disabled because app specs cannot increase the deployment target of the root
-  #  To use, increase the deployment target of this spec to 13.0 or higher
-  # s.app_spec 'WorkflowCombineSampleApp' do |app_spec|
-  #   app_spec.source_files = 'Samples/WorkflowCombineSampleApp/WorkflowCombineSampleApp/**/*.swift'
-  # end
-
-  # s.test_spec 'WorkflowCombineSampleAppTests' do |test_spec|
-  #   test_spec.dependency 'Development/WorkflowCombineSampleApp'
-  #   test_spec.requires_app_host = true
-  #   test_spec.app_host_name = 'Development/WorkflowCombineSampleApp'
-  #   test_spec.source_files = 'Samples/WorkflowCombineSampleApp/WorkflowCombineSampleAppUnitTests/**/*.swift'
-  # end
-# 
-  # s.test_spec 'WorkflowCombineTests' do |test_spec|
-  #   test_spec.requires_app_host = true
-  #   test_spec.source_files = 'WorkflowCombine/Tests/**/*.swift'
-  #   test_spec.framework = 'XCTest'
-  #   test_spec.dependency 'WorkflowTesting'
-  #   test_spec.dependency 'WorkflowCombineTesting'
-  # end
 end

Diff for: Samples/WorkflowCombineSampleApp/WorkflowCombineSampleApp/DemoWorker.swift

@@ -8,7 +8,6 @@
 import Combine
 import Workflow
 import WorkflowCombine
-import WorkflowUI
 
 // MARK: Workers
 
@@ -17,7 +16,7 @@ extension DemoWorkflow {
         typealias Output = Action
 
         // This publisher publishes the current date on a timer that fires every second
-        func run() -> AnyPublisher<Action, Never> {
+        func run() -> AnyPublisher<Output, Never> {
             Timer.publish(every: 1, on: .main, in: .common)
                 .autoconnect()
                 .map { Action(publishedDate: $0) }

Diff for: Samples/WorkflowCombineSampleApp/WorkflowCombineSampleAppUnitTests/DemoWorkflowTests.swift

@@ -12,7 +12,7 @@ import XCTest
 @testable import Development_WorkflowCombineSampleApp
 
 class DemoWorkflowTests: XCTestCase {
-    func test_workflowIsRenderedEverySecondForFiveSeconds() {
+    func test_demoWorkflow_publishesNewDate() {
         let expectedDate = Date(timeIntervalSince1970: 0)
 
         DemoWorkflow

Diff for: WorkflowCombine/Sources/Publisher+Extensions.swift

@@ -0,0 +1,34 @@
+//
+//  Publisher+Extensions.swift
+//  WorkflowCombine
+//
+//  Created by Soo Rin Park on 11/3/21.
+//
+
+#if canImport(Combine) && swift(>=5.1)
+
+    import Combine
+    import Foundation
+    import Workflow
+
+    @available(iOS 13.0, macOS 10.15, *)
+    /// This is a workaround to the fact you extensions of protocols cannot have an inheritance clause.
+    /// a previous solution had extending the `AnyPublisher` to conform to `AnyWorkflowConvertible`,
+    /// but was limited in the fact that rendering was only available to `AnyPublisher`s.
+    /// this solutions makes it so that all publishers can render its view.
+    extension Publisher where Failure == Never {
+        public func running<Parent>(in context: RenderContext<Parent>, key: String = "") where
+            Output == AnyWorkflowAction<Parent> {
+            asAnyWorkflow().rendered(in: context, key: key, outputMap: { $0 })
+        }
+
+        public func mapOutput<NewOutput>(_ transform: @escaping (Output) -> NewOutput) -> AnyWorkflow<Void, NewOutput> {
+            asAnyWorkflow().mapOutput(transform)
+        }
+
+        func asAnyWorkflow() -> AnyWorkflow<Void, Output> {
+            PublisherWorkflow(publisher: self).asAnyWorkflow()
+        }
+    }
+
+#endif

Diff for: WorkflowCombine/Sources/PublisherWorkflow.swift

@@ -20,14 +20,6 @@
     import Foundation
     import Workflow
 
-    @available(iOS 13.0, macOS 10.15, *)
-
-    extension AnyPublisher: AnyWorkflowConvertible where Failure == Never {
-        public func asAnyWorkflow() -> AnyWorkflow<Void, Output> {
-            return PublisherWorkflow(publisher: self).asAnyWorkflow()
-        }
-    }
-
     @available(iOS 13.0, macOS 10.15, *)
     struct PublisherWorkflow<WorkflowPublisher: Publisher>: Workflow where WorkflowPublisher.Failure == Never {
         public typealias Output = WorkflowPublisher.Output

Diff for: WorkflowCombine/Sources/Worker.swift

@@ -88,7 +88,6 @@
                     )
                     .map { AnyWorkflowAction<Self>(sendingOutput: $0) }
             }
-            .eraseToAnyPublisher()
             .running(in: context, key: state.uuidString)
         }
     }

Diff for: WorkflowCombine/Tests/Helpers/AnyPublisherTesting.swift renamed to WorkflowCombine/Tests/Helpers/PublisherTesting.swift

@@ -30,13 +30,13 @@
         /// - Parameters:
         ///   - producingOutput: An output that should be returned when this worker is requested, if any.
         ///   - key: Key to expect this `Workflow` to be rendered with.
-        public func expectPublisher<OutputType>(
-            producingOutput output: OutputType? = nil,
-            key: String = "",
-            file: StaticString = #file, line: UInt = #line
-        ) -> RenderTester<WorkflowType> {
+        public func expectPublisher<PublisherType: Publisher>(
+            publisher: PublisherType.Type,
+            output: PublisherType.Output,
+            key: String = ""
+        ) -> RenderTester<WorkflowType> where PublisherType.Failure == Never {
             expectWorkflow(
-                type: PublisherWorkflow<AnyPublisher<OutputType, Never>>.self,
+                type: PublisherWorkflow<PublisherType>.self,
                 key: key,
                 producingRendering: (),
                 producingOutput: output,

Diff for: WorkflowCombine/Tests/AnyPublisherTests.swift renamed to WorkflowCombine/Tests/PublisherTests.swift

@@ -20,11 +20,11 @@ import Workflow
 import XCTest
 @testable import WorkflowCombine
 
-class AnyPublisherTests: XCTestCase {
+class PublisherTests: XCTestCase {
     func testPublisherWorkflow() {
         TestWorkflow()
             .renderTester()
-            .expectPublisher(producingOutput: 1, key: "123")
+            .expectPublisher(publisher: Publishers.Sequence<[Int], Never>.self, output: 1, key: "123")
             .render {}
     }
 
@@ -34,22 +34,21 @@ class AnyPublisherTests: XCTestCase {
 
         func render(state: State, context: RenderContext<Self>) -> Rendering {
             [1].publisher
-                .eraseToAnyPublisher()
                 .mapOutput { _ in AnyWorkflowAction<TestWorkflow>.noAction }
                 .running(in: context, key: "123")
         }
     }
 
     func test_publisherWorkflow_usesSideEffectWithKey() {
-        let publisher = Just(1).eraseToAnyPublisher()
+        let publisher = Just(1)
         PublisherWorkflow(publisher: publisher)
             .renderTester()
             .expectSideEffect(key: "")
             .render { _ in }
     }
 
     func test_output() {
-        let publisher = Just(1).eraseToAnyPublisher()
+        let publisher = Just(1)
 
         let host = WorkflowHost(
             workflow: PublisherWorkflow(publisher: publisher)
@@ -72,7 +71,7 @@ class AnyPublisherTests: XCTestCase {
         let publisher = [1, 2, 3].publisher
 
         let host = WorkflowHost(
-            workflow: PublisherWorkflow(publisher: publisher.eraseToAnyPublisher())
+            workflow: PublisherWorkflow(publisher: publisher)
         )
 
         let expectation = XCTestExpectation()

Diff for: WorkflowCombine/Tests/WorkerTests.swift

@@ -136,14 +136,13 @@ class WorkerTests: XCTestCase {
         }
 
         struct TestWorker: Worker {
-            typealias Output = WorkerPublisher.Output
-            typealias WorkerPublisher = AnyPublisher<Int, Never>
+            typealias Output = Int
 
             func isEquivalent(to otherWorker: TestWorker) -> Bool {
                 true
             }
 
-            func run() -> WorkerPublisher {
+            func run() -> AnyPublisher<Int, Never> {
                 [1, 2].publisher
                     .delay(for: .milliseconds(1), scheduler: RunLoop.main)
                     .eraseToAnyPublisher()
@@ -194,11 +193,7 @@ private struct PublisherTestWorkflow: Workflow {
 
 private struct PublisherTestWorker: Worker {
     typealias Output = Int
-    func run() -> AnyPublisher<Int, Never> {
-        Just(1).eraseToAnyPublisher()
-    }
+    func run() -> Just<Int> { Just(1) }
 
-    func isEquivalent(to otherWorker: PublisherTestWorker) -> Bool {
-        true
-    }
+    func isEquivalent(to otherWorker: PublisherTestWorker) -> Bool { true }
 }