fix(core): same-time sets at 0 land in authored order on the first frame

packages/core/src/runtime/adapters/gsap.steps.test.ts

@@ -30,6 +30,16 @@ describe("gsap adapter on a step", () => {
     expect(film.shown()).toEqual([false, true, false]);
   });
 
+  it.each([undefined, 1, 2.7])(
+    "shows the first step's frame when seeking to 0 from %s s",
+    (from) => {
+      const film = steppedFilm();
+      if (from !== undefined) film.timeline.totalTime(from, true);
+      film.adapter.seek({ time: 0 });
+      expect(film.shown()).toEqual([true, false, false]);
+    },
+  );
+
   it("fires a call on the step once when seeking onto it twice", () => {
     const film = steppedFilm();
     film.adapter.seek({ time: 2.5 });

packages/core/src/runtime/adapters/gsap.ts

@@ -57,14 +57,20 @@ function renderOntoInAuthoredOrder(
   timeline.totalTime(below ? t - REDRAW_STEP : t + REDRAW_STEP, true);
   primeTweensStartingAt(children, t, below ? REDRAW_STEP : 0);
   timeline.totalTime(t, true);
-  if (!below && structure) reapplyStepsInAuthoredOrder(timeline, structure, t);
+  if (!below) reapplyStepsInAuthoredOrder(timeline, structure ?? ownStructureOf(children), t);
+}
+
+function ownStructureOf(children: unknown[]): GsapStructureKey | undefined {
+  const owner = (children[0] as GsapPlaced | undefined)?.parent;
+  return owner ? { owner, version: "" } : undefined;
 }
 
 function reapplyStepsInAuthoredOrder(
   timeline: { getChildren?: RuntimeTimelineLike["getChildren"] },
-  structure: GsapStructureKey,
+  structure: GsapStructureKey | undefined,
   t: number,
 ): void {
+  if (!structure) return;
   for (const step of stepsAt(timeline, structure, t)) {
     const { ratio, _zTime, _act } = step;
     step.render(0, true, true);
@@ -366,7 +372,9 @@ function stepsAt(
   structure: GsapStructureKey,
   t: number,
 ): GsapStep[] {
-  const { points } = placedLandingMarks(timeline, structure);
+  const { points } = structure.version
+    ? placedLandingMarks(timeline, structure)
+    : placeLandingMarks(timeline, structure);
   const steps: GsapStep[] = [];
   for (let i = firstPointFrom(points, t - PLAYHEAD_FLOAT_NOISE); i < points.length; i++) {
     if (points[i]!.at > t + PLAYHEAD_FLOAT_NOISE) break;