Art Studio: restart-from-stage 400 "Sequence contains no elements" (Mongo MaxAsync on empty) #445

New Issue

2026-07-07T05:11:17Z

spikerj commented

2026-07-07 05:11:17 +00:00

Symptom (production, learn.spikersoft.com)

Staff clicking to restart the modeling stage of an art asset gets an instant 400 with body Sequence contains no elements — no run is dispatched.

POST https://api.spikersoft.com/api/artstudio/{id}/restart/modeling → 400

Root cause

RestartFromStageCommandHandler computes the new run's retry count as MAX(RetryCount) over the asset's prior runs for the restarted stage:

var previousRetryCount = await context.ArtAssetStageRuns
    .Where(r => r.AssetId == request.AssetId && r.Stage == request.Stage)
    .Select(r => (int?)r.RetryCount)
    .MaxAsync(cancellationToken) ?? -1;

The (int?) + ?? -1 is the relational idiom for "empty → null". But this runs on the MongoDB EF Core provider, where MaxAsync over an empty sequence throws InvalidOperationException("Sequence contains no elements") instead of returning null. When the restarted stage has no prior run — restarting from a stage that failed before producing a run, or that never ran — the query is empty → throw. ArtStudioController.RestartFromStage catches InvalidOperationException and returns it as 400 BadRequest(ex.Message), so the raw provider message reaches the browser.

Fix

Materialize + Max in memory with an explicit empty fallback (provider-agnostic; retry counts per stage are few and restart is rare). Proven with an integration test that pins the Mongo behavior (the buggy MaxAsync throws; the fixed pattern returns -1).

PR incoming.

Found via the newly-online integration suite running on an Apple-Silicon dev host (#444).

## Symptom (production, learn.spikersoft.com) Staff clicking to restart the **modeling** stage of an art asset gets an instant **400** with body `Sequence contains no elements` — no run is dispatched. ``` POST https://api.spikersoft.com/api/artstudio/{id}/restart/modeling → 400 ``` ## Root cause `RestartFromStageCommandHandler` computes the new run's retry count as `MAX(RetryCount)` over the asset's **prior runs for the restarted stage**: ```csharp var previousRetryCount = await context.ArtAssetStageRuns .Where(r => r.AssetId == request.AssetId && r.Stage == request.Stage) .Select(r => (int?)r.RetryCount) .MaxAsync(cancellationToken) ?? -1; ``` The `(int?)` + `?? -1` is the **relational** idiom for "empty → null". But this runs on the **MongoDB EF Core provider**, where `MaxAsync` over an **empty** sequence **throws** `InvalidOperationException("Sequence contains no elements")` instead of returning null. When the restarted stage has **no prior run** — restarting from a stage that failed before producing a run, or that never ran — the query is empty → throw. `ArtStudioController.RestartFromStage` catches `InvalidOperationException` and returns it as `400 BadRequest(ex.Message)`, so the raw provider message reaches the browser. ## Fix Materialize + `Max` in memory with an explicit empty fallback (provider-agnostic; retry counts per stage are few and restart is rare). Proven with an integration test that pins the Mongo behavior (the buggy `MaxAsync` throws; the fixed pattern returns `-1`). PR incoming. Found via the newly-online integration suite running on an Apple-Silicon dev host (#444).

spikerj referenced this issue

2026-07-07 22:10:24 +00:00

[Bug][Prod] Art Studio 'modeling' stage fails — TripoSG model manifest missing on prod host #455

spikerj commented

2026-07-08 02:01:32 +00:00

Fixed and merged to master in commit 7c6271c (present on current master 1638bf0). RestartFromStageCommandHandler now materializes the prior retry counts with ToListAsync and takes priorRetryCounts.Count > 0 ? priorRetryCounts.Max() : -1 — provider-agnostic, no MaxAsync-on-empty throw. The pinning integration test RestartFromStageRetryCountTests ships alongside it. Closing.

Fixed and merged to `master` in commit `7c6271c` (present on current master `1638bf0`). `RestartFromStageCommandHandler` now materializes the prior retry counts with `ToListAsync` and takes `priorRetryCounts.Count > 0 ? priorRetryCounts.Max() : -1` — provider-agnostic, no `MaxAsync`-on-empty throw. The pinning integration test `RestartFromStageRetryCountTests` ships alongside it. Closing.

spikerj closed this issue

2026-07-08 02:01:39 +00:00

spikerj referenced this issue

2026-07-21 20:14:51 +00:00

[Infra][MinIO] Final GridFS slices: vault-files + photograph-previews → MinIO sole store (completes epic #413's GridFS retirement) #778

spikerj referenced this issue

2026-07-21 20:49:21 +00:00

[Infra][MinIO] Final GridFS slices: vault-files + photograph-previews → MinIO sole store (completes epic #413's GridFS retirement) #778

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