262: Deprecate Worker.createSideEffect in favour of RenderContext.runningSideEffect

Replace with runningSideEffect where possible or with a Worker<Unit> instead of
Worker<Nothing>.

Author: steve-the-edwards

workflow-core/src/main/java/com/squareup/workflow1/BaseRenderContext.kt

@@ -258,7 +258,7 @@ public fun <PropsT, StateT, OutputT, ChildRenderingT>
  * Ensures a [Worker] that never emits anything is running. Since [worker] can't emit anything,
  * it can't trigger any [WorkflowAction]s.
  *
- * A simple way to create workers that don't output anything is using [Worker.createSideEffect].
+ * If your [Worker] does not output anything, then simply use [runningSideEffect].
  *
  * @param key An optional string key that is used to distinguish between identical [Worker]s.
  */

workflow-core/src/main/java/com/squareup/workflow1/Worker.kt

@@ -185,7 +185,7 @@ public interface Worker<out OutputT> {
      * Shorthand for `flow { block() }.asWorker()`.
      *
      * Note: If your worker just needs to perform side effects and doesn't need to emit anything,
-     * use [createSideEffect] instead (since `Nothing` can't be used as a reified type parameter).
+     * do not use a [Worker] but instead all [BaseRenderContext::runningSideEffect]
      */
     @OptIn(ExperimentalTypeInference::class)
     public inline fun <reified OutputT> create(
@@ -201,14 +201,25 @@ public interface Worker<out OutputT> {
      * fun logOnEntered(message: String) = Worker.createSideEffect() {
      *   println("Entered state: $message")
      * }
+     * ```
      *
      * Note that all workers created with this method are equivalent from the point of view of
      * their [Worker.doesSameWorkAs] methods. A workflow that needs multiple simultaneous
      * side effects can either bundle them all together into a single `createSideEffect`
      * call, or can use the `key` parameter to [BaseRenderContext.runningWorker] to prevent
      * conflicts.
-     * ```
+     *
+     * Deprecated: This convenience extension is deprecated as redundant.
+     * [BaseRenderContext.runningSideEffect] can be used instead with a suspend function
+     * and a key to uniquely identify the side effect in the runtime.
      */
+    @Deprecated(
+      message = "Worker not needed, simply call RenderContext.runningSideEffect " +
+        "with a suspend fun.",
+      ReplaceWith(
+        expression = "runningSideEffect(key, block)"
+      )
+    )
     public fun createSideEffect(
       block: suspend () -> Unit
     ): Worker<Nothing> = TypedWorker(TYPE_OF_NOTHING, flow { block() })

workflow-runtime/src/test/java/com/squareup/workflow1/RenderWorkflowInTest.kt

@@ -364,11 +364,11 @@ class RenderWorkflowInTest {
   @Test fun `cancelling scope cancels runtime`() {
     var cancellationException: Throwable? = null
     val workflow = Workflow.stateless<Unit, Nothing, Unit> {
-      runningWorker(Worker.createSideEffect {
+      runningSideEffect(key = "test1") {
         suspendCancellableCoroutine { continuation ->
           continuation.invokeOnCancellation { cause -> cancellationException = cause }
         }
-      })
+      }
     }
     renderWorkflowIn(workflow, expectedSuccessScope, MutableStateFlow(Unit)) {}
     assertNull(cancellationException)
@@ -383,11 +383,11 @@ class RenderWorkflowInTest {
   @Test fun `failing scope cancels runtime`() {
     var cancellationException: Throwable? = null
     val workflow = Workflow.stateless<Unit, Nothing, Unit> {
-      runningWorker(Worker.createSideEffect {
+      runningSideEffect(key = "failing") {
         suspendCancellableCoroutine { continuation ->
           continuation.invokeOnCancellation { cause -> cancellationException = cause }
         }
-      })
+      }
     }
     renderWorkflowIn(workflow, expectedSuccessScope, MutableStateFlow(Unit)) {}
     assertNull(cancellationException)
@@ -418,13 +418,13 @@ class RenderWorkflowInTest {
   @Test fun `error from renderings collector cancels runtime`() {
     var cancellationException: Throwable? = null
     val workflow = Workflow.stateless<Unit, Nothing, Unit> {
-      runningWorker(Worker.createSideEffect {
+      runningSideEffect(key = "test") {
         suspendCancellableCoroutine { continuation ->
           continuation.invokeOnCancellation { cause ->
             cancellationException = cause
           }
         }
-      })
+      }
     }
     val renderings = renderWorkflowIn(workflow, allowedToFailScope, MutableStateFlow(Unit)) {}
 

workflow-runtime/src/test/java/com/squareup/workflow1/internal/WorkflowRunnerTest.kt

@@ -171,11 +171,11 @@ internal class WorkflowRunnerTest {
   @Test fun `cancelRuntime() cancels runtime`() {
     var cancellationException: Throwable? = null
     val workflow = Workflow.stateless<Unit, Nothing, Unit> {
-      runningWorker(Worker.createSideEffect {
+      runningSideEffect(key = "test side effect") {
         suspendCancellableCoroutine { continuation ->
           continuation.invokeOnCancellation { cause -> cancellationException = cause }
         }
-      })
+      }
     }
     val runner = WorkflowRunner(workflow, MutableStateFlow(Unit))
     runner.nextRendering()
@@ -209,11 +209,11 @@ internal class WorkflowRunnerTest {
   @Test fun `cancelling scope cancels runtime`() {
     var cancellationException: Throwable? = null
     val workflow = Workflow.stateless<Unit, Nothing, Unit> {
-      runningWorker(Worker.createSideEffect {
+      runningSideEffect(key = "test") {
         suspendCancellableCoroutine { continuation ->
           continuation.invokeOnCancellation { cause -> cancellationException = cause }
         }
-      })
+      }
     }
     val runner = WorkflowRunner(workflow, MutableStateFlow(Unit))
     runner.nextRendering()

workflow-rx2/src/main/java/com/squareup/workflow1/rx2/RxWorkers.kt

@@ -78,5 +78,8 @@ public inline fun <reified T : Any> Single<out T?>.asWorker(): Worker<T> =
  *
  * The key is required for this operator because there is no type information available to
  * distinguish workers.
+ *
+ * TODO: https://github.com/square/workflow-kotlin/issues/526 once this is removed.
  */
+@Suppress("DEPRECATION")
 public fun Completable.asWorker(): Worker<Nothing> = Worker.createSideEffect { await() }

workflow-testing/src/test/java/com/squareup/workflow1/WorkerCompositionIntegrationTest.kt

@@ -140,7 +140,9 @@ internal class WorkerCompositionIntegrationTest {
 
   @Test fun `runningWorker gets error`() {
     val workflow = Workflow.stateless<Unit, Unit, Unit> {
-      runningWorker(Worker.createSideEffect { throw ExpectedException() })
+      runningWorker(Worker.from<Unit> { throw ExpectedException() }) {
+        action {  }
+      }
     }
 
     assertFailsWith<ExpectedException> {
@@ -223,9 +225,11 @@ internal class WorkerCompositionIntegrationTest {
 
   @Test fun `runningWorker doesn't throw when worker finishes`() {
     // No-op worker, completes immediately.
-    val worker = Worker.createSideEffect {}
+    val worker = Worker.from {  }
     val workflow = Workflow.stateless<Unit, Unit, Unit> {
-      runningWorker(worker)
+      runningWorker(worker) {
+        action {  }
+      }
     }
 
     workflow.launchForTestingFromStartWith {

workflow-testing/src/test/java/com/squareup/workflow1/WorkerTest.kt

@@ -44,6 +44,7 @@ class WorkerTest {
     }
   }
 
+  @Suppress("DEPRECATION")
   @Test fun `createSideEffect returns equivalent workers`() {
     val worker1 = Worker.createSideEffect {}
     val worker2 = Worker.createSideEffect {}
@@ -52,6 +53,7 @@ class WorkerTest {
     assertTrue(worker1.doesSameWorkAs(worker2))
   }
 
+  @Suppress("DEPRECATION")
   @Test fun `createSideEffect runs`() {
     var ran = false
     val worker = Worker.createSideEffect {
@@ -63,6 +65,7 @@ class WorkerTest {
     }
   }
 
+  @Suppress("DEPRECATION")
   @Test fun `createSideEffect finishes`() {
     val worker = Worker.createSideEffect {}
 
@@ -71,6 +74,7 @@ class WorkerTest {
     }
   }
 
+  @Suppress("DEPRECATION")
   @Test fun `createSideEffect propagates exceptions`() {
     val worker = Worker.createSideEffect { throw ExpectedException() }