fix(workflow): forward parent pointer when spawning a child with discard:true

.changeset/forward-parent-pointer-discard.md

@@ -0,0 +1,5 @@
+---
+"@effect/workflow": patch
+---
+
+Forward the parent pointer when spawning a child workflow with `discard: true`

packages/cluster/test/ClusterWorkflowEngine.test.ts

@@ -245,6 +245,36 @@ describe.concurrent("ClusterWorkflowEngine", () => {
 
       assert.isTrue(flags.get("catch"))
     }).pipe(Effect.provide(TestWorkflowLayer)))
+
+  it.effect("forwards parent pointer when spawning a child with discard:true", () =>
+    Effect.gen(function*() {
+      const driver = yield* MessageStorage.MemoryDriver
+      const fiber = yield* DiscardParentWorkflow.execute({ id: "discard-parent-1" }).pipe(
+        Effect.fork
+      )
+      yield* TestClock.adjust(1)
+      yield* Fiber.join(fiber)
+
+      const findRun = (entityType: string) =>
+        driver.journal.find(
+          (envelope) =>
+            envelope._tag === "Request" &&
+            envelope.address.entityType === entityType &&
+            envelope.tag === "run"
+        )
+      const parentRun = findRun("Workflow/DiscardParentWorkflow")
+      const childRun = findRun("Workflow/DiscardChildWorkflow")
+      assert.exists(parentRun, "expected a run envelope for the parent workflow")
+      assert.exists(childRun, "expected a run envelope for the child workflow")
+
+      const childPayload = (childRun as { payload: Record<string, unknown> }).payload
+      const parent = childPayload["~@effect/workflow/parent"] as
+        | { workflowName: string; executionId: string }
+        | undefined
+      assert.exists(parent, "child payload should carry the parent pointer")
+      expect(parent!.workflowName).toEqual("DiscardParentWorkflow")
+      expect(parent!.executionId).toEqual((parentRun as { address: { entityId: string } }).address.entityId)
+    }).pipe(Effect.provide(TestWorkflowLayer)))
 })
 
 const TestShardingConfig = ShardingConfig.layer({
@@ -498,6 +528,34 @@ const ChildWorkflowLayer = ChildWorkflow.toLayer(Effect.fnUntraced(function*() {
   flags.set("child-end", true)
 }))
 
+const DiscardParentWorkflow = Workflow.make({
+  name: "DiscardParentWorkflow",
+  payload: { id: Schema.String },
+  idempotencyKey(payload) {
+    return payload.id
+  }
+})
+
+const DiscardChildWorkflow = Workflow.make({
+  name: "DiscardChildWorkflow",
+  payload: { id: Schema.String },
+  idempotencyKey(payload) {
+    return payload.id
+  }
+})
+
+const DiscardParentWorkflowLayer = DiscardParentWorkflow.toLayer(
+  Effect.fnUntraced(function*({ id }) {
+    yield* DiscardChildWorkflow.execute({ id: `${id}-child` }, { discard: true })
+  })
+)
+
+const DiscardChildWorkflowLayer = DiscardChildWorkflow.toLayer(
+  Effect.fnUntraced(function*() {
+    return yield* Effect.void
+  })
+)
+
 const SuspendOnFailureWorkflow = Workflow.make({
   name: "SuspendOnFailureWorkflow",
   payload: {
@@ -556,6 +614,8 @@ const TestWorkflowLayer = EmailWorkflowLayer.pipe(
   Layer.merge(DurableRaceWorkflowLayer),
   Layer.merge(ParentWorkflowLayer),
   Layer.merge(ChildWorkflowLayer),
+  Layer.merge(DiscardParentWorkflowLayer),
+  Layer.merge(DiscardChildWorkflowLayer),
   Layer.merge(SuspendOnFailureWorkflowLayer),
   Layer.merge(CatchWorkflowLayer),
   Layer.provideMerge(Flags.Default),

packages/workflow/src/WorkflowEngine.ts

@@ -366,7 +366,8 @@ export const makeUnsafe = (options: Encoded): WorkflowEngine["Type"] =>
         yield* options.execute(self, {
           executionId,
           payload: payload as object,
-          discard: true
+          discard: true,
+          parent: Option.getOrUndefined(parentInstance)
         })
         return executionId
       }