Use publishers in Effect.debounce and Effect.deferred (#1331)

(cherry picked from commit adf7cc8e365238c03ead4c48ba66afd5d2cacadc)

# Conflicts:
#	Sources/ComposableArchitecture/Effects/Debouncing.swift
#	Sources/ComposableArchitecture/Effects/Deferring.swift

Author: stephencelis

Sources/ComposableArchitecture/Effects/Cancellation.swift

@@ -166,9 +166,36 @@ extension Effect {
 
 /// Execute an operation with a cancellation identifier.
 ///
-/// If the operation is in-flight when `Task.cancel(id:)` is called with the same identifier, the
+/// If the operation is in-flight when `Task.cancel(id:)` is called with the same identifier, or
 /// operation will be cancelled.
 ///
+/// ```
+/// enum CancelID.self {}
+///
+/// await withTaskCancellation(id: CancelID.self) {
+///   // ...
+/// }
+/// ```
+///
+/// ### Debouncing tasks
+///
+/// When paired with a scheduler, this function can be used to debounce a unit of async work by
+/// specifying the `cancelInFlight`, which will automatically cancel any in-flight work with the
+/// same identifier:
+///
+/// ```swift
+/// enum CancelID {}
+///
+/// return .task {
+///   await withTaskCancellation(id: CancelID.self, cancelInFlight: true) {
+///     try await environment.scheduler.sleep(for: .seconds(0.3))
+///     return await .debouncedResponse(
+///       TaskResult { try await environment.request() }
+///     )
+///   }
+/// }
+/// ```
+///
 /// - Parameters:
 ///   - id: A unique identifier for the operation.
 ///   - cancelInFlight: Determines if any in-flight operation with the same identifier should be

Sources/ComposableArchitecture/Effects/Debouncing.swift

@@ -24,6 +24,26 @@ extension Effect {
   ///   - dueTime: The duration you want to debounce for.
   ///   - scheduler: The scheduler you want to deliver the debounced output to.
   /// - Returns: An effect that publishes events only after a specified time elapses.
+  @available(
+    iOS,
+    deprecated: 9999.0,
+    message: "Use 'withTaskCancellation(id: _, cancelInFlight: true)' in 'Effect.run', instead."
+  )
+  @available(
+    macOS,
+    deprecated: 9999.0,
+    message: "Use 'withTaskCancellation(id: _, cancelInFlight: true)' in 'Effect.run', instead."
+  )
+  @available(
+    tvOS,
+    deprecated: 9999.0,
+    message: "Use 'withTaskCancellation(id: _, cancelInFlight: true)' in 'Effect.run', instead."
+  )
+  @available(
+    watchOS,
+    deprecated: 9999.0,
+    message: "Use 'withTaskCancellation(id: _, cancelInFlight: true)' in 'Effect.run', instead."
+  )
   public func debounce(
     id: AnyHashable,
     for dueTime: TimeInterval,
@@ -32,7 +52,7 @@ extension Effect {
     switch self.operation {
     case .none:
       return .none
-    case .producer:
+    case .producer, .run:
       return Self(
         operation: .producer(
           SignalProducer<Void, Never>.init(value: ())
@@ -42,23 +62,6 @@ extension Effect {
         )
       )
       .cancellable(id: id, cancelInFlight: true)
-    case let .run(priority, operation):
-      return Self(
-        operation: .run(priority) { send in
-          await withTaskCancellation(id: id, cancelInFlight: true) {
-            do {
-              try await scheduler.sleep(for: .nanoseconds(Int(dueTime * TimeInterval(NSEC_PER_SEC))))
-              await operation(
-                Send { output in
-                  scheduler.schedule {
-                    send(output)
-                  }
-                }
-              )
-            } catch {}
-          }
-        }
-      )
     }
   }
 

Sources/ComposableArchitecture/Effects/Deferring.swift

@@ -29,29 +29,14 @@ extension Effect {
     switch self.operation {
     case .none:
       return .none
-    case .producer:
+    case .producer, .run:
       return Self(
         operation: .producer(
           SignalProducer<Void, Never>(value: ())
             .delay(dueTime, on: scheduler)
             .flatMap(.latest) { self.producer.observe(on: scheduler) }
         )
       )
-    case let .run(priority, operation):
-      return Self(
-        operation: .run(priority) { send in
-          do {
-            try await scheduler.sleep(for: .nanoseconds(Int(dueTime * TimeInterval(NSEC_PER_SEC))))
-            await operation(
-              Send { output in
-                scheduler.schedule {
-                  send(output)
-                }
-              }
-            )
-          } catch {}
-        }
-      )
     }
   }
 }

Tests/ComposableArchitectureTests/EffectFailureTests.swift

@@ -10,7 +10,7 @@ import XCTest
 
       XCTExpectFailure {
         $0.compactDescription == """
-          An 'Effect.task' returned from "ComposableArchitectureTests/EffectFailureTests.swift:24" \
+          An 'Effect.task' returned from "ComposableArchitectureTests/EffectFailureTests.swift:23" \
           threw an unhandled error. …
 
               EffectFailureTests.Unexpected()
@@ -33,7 +33,7 @@ import XCTest
 
       XCTExpectFailure {
         $0.compactDescription == """
-          An 'Effect.run' returned from "ComposableArchitectureTests/EffectFailureTests.swift:47" \
+          An 'Effect.run' returned from "ComposableArchitectureTests/EffectFailureTests.swift:46" \
           threw an unhandled error. …
 
               EffectFailureTests.Unexpected()