fix(peloton): accept nullable workout fields

docs/production-incident-baseline.md

@@ -18405,3 +18405,36 @@ Drizzle schema and runtime Zod schemas. Findings and remediations:
   old worker reaches `Shutdown complete` without exit 137, verify the timed-out
   Strava job retries and completes, observe no fixed-release 4N/2K events
   across a subsequent rollout, then resolve both Sentry issues.
+
+## 2026-07-26 — Peloton Workout Response Drift Blocked Sync
+
+- **Status:** Direct source fix validated locally; merge and production
+  deployment pending.
+- **Symptoms:** Scheduled Peloton syncs failed at the client response boundary
+  in
+  [Sentry issue DOFEK-SERVER-5E](https://east-bay-software.sentry.io/issues/DOFEK-SERVER-5E).
+- **User impact:** The affected Peloton connection could not import any workout
+  page because validation rejected the complete page before parsing began.
+- **Evidence:** Five consecutive production events from `14:30` through
+  `16:30` UTC reported the same response drift. Peloton returned `null` for
+  workout `title`, `end_time`, `metrics_type`, `peloton_id`, and `strava_id`,
+  and omitted `ride.instructor.id`; the runtime schema accepted only omitted
+  optional strings and required a numeric end time and instructor ID.
+- **Root cause:** The client boundary modeled several optional upstream fields
+  as undefined-only even though the observed API payload uses both JSON `null`
+  and omission for absence. The schema therefore rejected valid unfinished and
+  partially linked workouts before the provider could normalize them.
+- **Fix / mitigation:** Accept only the observed nullability and omission:
+  nullable title and source-link fields, nullable-but-present `end_time`, and
+  an optional instructor ID. Keep every other identity and timestamp field
+  required, preserve the upstream nulls in the client response, and normalize
+  a null end time to the existing unfinished-workout behavior only in the
+  parsed provider DTO.
+- **Validation:** A production-shaped regression first failed with the exact
+  six Zod paths reported by Sentry. After the schema correction, all 17 focused
+  client and parsing tests pass, the root TypeScript typecheck passes, targeted
+  Biome checks report no findings, and the changed parser kills all 13
+  generated mutants.
+- **Remaining risk / follow-up:** Merge through normal CI, deploy, observe a
+  successful scheduled Peloton sync on the fixed release, and then resolve
+  DOFEK-SERVER-5E.

packages/peloton-client/src/client.test.ts

@@ -115,6 +115,45 @@ describe("PelotonClient", () => {
     await expect(unavailable.getWorkouts()).rejects.toBeInstanceOf(PelotonServiceError);
   });
 
+  it("accepts observed nullable workout fields and missing instructor IDs", async () => {
+    const response = {
+      data: [
+        {
+          id: "workout-1",
+          status: "COMPLETE",
+          fitness_discipline: "cycling",
+          title: null,
+          created_at: 1_709_280_000,
+          start_time: 1_709_280_000,
+          end_time: null,
+          total_work: 0,
+          is_total_work_personal_record: false,
+          metrics_type: null,
+          peloton_id: null,
+          strava_id: null,
+          ride: {
+            id: "ride-1",
+            title: "Recovery Ride",
+            duration: 1_800,
+            instructor: { name: "Coach" },
+          },
+        },
+      ],
+      total: 1,
+      count: 1,
+      page: 0,
+      limit: 20,
+      page_count: 1,
+      sort_by: "-created_at",
+      show_next: false,
+      show_previous: false,
+    };
+    const responses = [Response.json({ id: "user-123" }), Response.json(response)];
+    const client = new PelotonClient("secret", async () => responses.shift() ?? Response.error());
+
+    await expect(client.getWorkouts()).resolves.toEqual(response);
+  });
+
   it("requests and validates performance graphs", async () => {
     const graph = {
       duration: 5,

packages/peloton-client/src/parsing.test.ts

@@ -117,6 +117,19 @@ describe("parseWorkout", () => {
 
     expect(parsed.raw.instructor).toBeUndefined();
   });
+
+  it("treats nullable completion and source identifiers as absent", () => {
+    const parsed = parseWorkout({
+      ...workout,
+      end_time: null,
+      peloton_id: null,
+      strava_id: null,
+    });
+
+    expect(parsed.endedAt).toBeUndefined();
+    expect(parsed.stravaId).toBeUndefined();
+    expect(parsed.raw.pelotonClassId).toBeUndefined();
+  });
 });
 
 describe("parsePerformanceGraph", () => {

packages/peloton-client/src/parsing.ts

@@ -34,7 +34,8 @@ export interface ParsedPelotonWorkout {
 
 export function parseWorkout(workout: PelotonWorkout): ParsedPelotonWorkout {
   const startedAt = new Date(workout.start_time * 1000);
-  const endedAt = workout.end_time > 0 ? new Date(workout.end_time * 1000) : undefined;
+  const endTime = workout.end_time ?? 0;
+  const endedAt = endTime > 0 ? new Date(endTime * 1000) : undefined;
   const stravaId = workout.strava_id && workout.strava_id !== "-1" ? workout.strava_id : undefined;
 
   return {

packages/peloton-client/src/types.ts

@@ -1,7 +1,7 @@
 import { z } from "zod";
 
 export const pelotonInstructorSchema = z.object({
-  id: z.string(),
+  id: z.string().optional(),
   name: z.string(),
   image_url: z.string().optional(),
 });
@@ -21,21 +21,21 @@ export const pelotonWorkoutSchema = z.object({
   status: z.string(),
   fitness_discipline: z.string(),
   name: z.string().optional(),
-  title: z.string().optional(),
+  title: z.string().nullish(),
   created_at: z.number(),
   start_time: z.number(),
-  end_time: z.number(),
+  end_time: z.number().nullable(),
   total_work: z.number(),
   is_total_work_personal_record: z.boolean(),
-  metrics_type: z.string().optional(),
+  metrics_type: z.string().nullish(),
   device_type: z.string().optional(),
   platform: z.string().optional(),
-  peloton_id: z.string().optional(),
+  peloton_id: z.string().nullish(),
   workout_type: z.string().optional(),
   has_pedaling_metrics: z.boolean().optional(),
   has_leaderboard_metrics: z.boolean().optional(),
   timezone: z.string().optional(),
-  strava_id: z.string().optional(),
+  strava_id: z.string().nullish(),
   ride: pelotonRideSchema.optional(),
   total_leaderboard_users: z.number().optional(),
   leaderboard_rank: z.number().optional(),