From 20242515ec103d4fee912fca534260d98f08d6b6 Mon Sep 17 00:00:00 2001
From: James <james.russo@heygen.com>
Date: Mon, 11 May 2026 19:03:02 +0000
Subject: [PATCH] refactor(producer): make sequencer the sole writer of
 job.duration/totalFrames
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The probe stage previously assigned `job.duration` and `job.totalFrames`
inside its body AND the sequencer re-asserted them after the call to
restore TS narrowing. Two writers for the same field is a maintenance
hazard — a future refactor could drop one and create a silent skew.

Move ownership: the stage computes `duration` and `totalFrames` and
returns them; the sequencer is the sole writer onto the `RenderJob`.
This also aligns with the eventual chunk-worker model where a chunk
running in a separate process cannot mutate the orchestrator's `job`.

No observable behavior change. `job.duration` / `job.totalFrames` end
up with the same values; the zero-duration `throw` still happens
inside the stage (now using the local `duration` constant) before any
sequencer-side assignment. Verified by:

- `bun run --filter @hyperframes/producer typecheck` clean
- `bun test packages/producer/src/services/` 175 pass / 1 pre-existing
  unrelated failure on `main`

Review feedback addressed: vanceingalls on #719.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 .../producer/src/services/render/stages/probeStage.ts | 11 ++++++-----
 packages/producer/src/services/renderOrchestrator.ts  |  6 ++----
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/packages/producer/src/services/render/stages/probeStage.ts b/packages/producer/src/services/render/stages/probeStage.ts
index e1655db55..f3ba06adc 100644
--- a/packages/producer/src/services/render/stages/probeStage.ts
+++ b/packages/producer/src/services/render/stages/probeStage.ts
@@ -13,8 +13,11 @@
  *     plan lists recompile as a sibling phase.
  *   - `composition` (videos/audios/duration) is mutated in place — callers
  *     downstream see the reconciled view through the same object reference.
- *   - `job.duration` and `job.totalFrames` are assigned at the same code
- *     points.
+ *   - The stage computes the final composition `duration` and `totalFrames`
+ *     and returns them. Assigning those values onto the `RenderJob` is the
+ *     sequencer's responsibility — a future chunk worker can't mutate the
+ *     orchestrator's `job` object, and keeping the assignment in one place
+ *     prevents the same value living in two writers.
  *   - The "Composition duration is 0" diagnostic builds the same hint
  *     string from the same console-buffer regex and `__timelines` probe.
  *   - The post-probe "failed network requests" warning fires with the same
@@ -288,10 +291,8 @@ export async function runProbeStage(input: ProbeStageInput): Promise<ProbeStageR
   }
   const browserProbeMs = Date.now() - probeStart;
 
-  job.duration = composition.duration;
-  job.totalFrames = Math.ceil(composition.duration * fpsToNumber(job.config.fps));
   const duration = composition.duration;
-  const totalFrames = job.totalFrames;
+  const totalFrames = Math.ceil(duration * fpsToNumber(job.config.fps));
 
   if (duration <= 0) {
     // Gather diagnostics to help users understand why the render would produce a black video.
diff --git a/packages/producer/src/services/renderOrchestrator.ts b/packages/producer/src/services/renderOrchestrator.ts
index 8e0192a50..fbed2b3f1 100644
--- a/packages/producer/src/services/renderOrchestrator.ts
+++ b/packages/producer/src/services/renderOrchestrator.ts
@@ -2153,10 +2153,8 @@ export async function executeRenderJob(
     fileServer = probeResult.fileServer;
     probeSession = probeResult.probeSession;
     lastBrowserConsole = probeResult.lastBrowserConsole;
-    // Re-assign through the typed result so the rest of the function sees
-    // `job.duration` and `job.totalFrames` narrowed to `number` — the
-    // assignments happened inside `runProbeStage`, but mirroring them here
-    // restores TypeScript's control-flow narrowing.
+    // The probe stage produces `duration` / `totalFrames` values; the
+    // sequencer owns the `RenderJob` and writes them onto it.
     job.duration = probeResult.duration;
     job.totalFrames = probeResult.totalFrames;
     const totalFrames = probeResult.totalFrames;