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

[jcalem-rogo]

Summary

Workflow.execute(payload, { discard: true }) takes a fast path inside WorkflowEngine.execute that omits the parent option when delegating to the underlying engine. As a result, ClusterWorkflowEngine never writes "~@effect/workflow/parent" into the child's persisted cluster_messages.payload row.

The non-discard branch a few lines below DOES forward parent, so the discard path looks like an oversight — parent carries two concerns and only one of them (interrupt linkage) is moot for discarded children. The other (the persisted causality breadcrumb) is still load-bearing for any observability surface that wants to reconstruct a parent/child workflow tree from message storage.

Before this fix:

if (opts.discard) {
  yield* options.execute(self, {
    executionId,
    payload: payload as object,
    discard: true
    //                ↑ no `parent` — child's payload is missing the parent pointer
  })
  return executionId
}

After:

if (opts.discard) {
  yield* options.execute(self, {
    executionId,
    payload: payload as object,
    discard: true,
    parent: Option.getOrUndefined(parentInstance)
  })
  return executionId
}

The fix is one line. The parent option is already typed as optional on the engine's execute signature, so no other surfaces change.

Why this matters

The dominant fan-out shape in @effect/cluster workflows — Effect.forEach(items, (item) => ChildWorkflow.execute(item, { discard: true })) — was leaving every child's payload without a parent pointer. Tools that read cluster_messages to reconstruct a Temporal-like workflow tree end up with orphaned children and no way to link them back to their parent, except by falling back to OTel trace_id grouping (which is lossy and ambiguous for nested fan-outs).

Test

Added a regression test in packages/cluster/test/ClusterWorkflowEngine.test.ts that spawns a child with discard: true and asserts the persisted child run-envelope carries "~@effect/workflow/parent" pointing back at the parent's actual executionId.

Changeset

@effect/workflow: patch.

Test plan

• pnpm vitest run in packages/cluster — all 9 tests pass, including the new one.
• pnpm vitest run in packages/workflow — all 6 tests pass.
• tsc -b clean across both packages.
• eslint clean on the touched files.

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: fdd957b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 6 packages

Name	Type
@effect/workflow	Patch
@effect/cluster	Patch
@effect/platform-bun	Patch
@effect/platform-node-shared	Patch
@effect/platform-node	Patch
@effect/sql-clickhouse	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR