Job cancellation doesn't work in database/sql driver

Hi!

I am using the example SortWorker job with small adjustments to test longer-running jobs with cancellation but it does not seem to work.

const SortJobKind = "sort"

type SortArgs struct {
  Strings []string `json:"strings"`
}

func (SortArgs) Kind() string {
  return SortJobKind
}

type SortWorker struct {
  river.WorkerDefaults[SortArgs]
}

func (w *SortWorker) Work(ctx context.Context, job *river.Job[SortArgs]) error {
  log.Printf("STARTING: %d", job.ID)
  select {
  case <-ctx.Done():
    log.Printf("CANCELLED: %d", job.ID)
    return ctx.Err()
  case <-time.After(20 * time.Second):
    log.Printf("WILL DO: %d", job.ID)
  }

  items := job.Args.Strings
  sort.Strings(items)
  log.Printf("RESULT: %+v\n", items)
  return nil
}

When the job appears in the User Interface (riverui), I click Cancel but the job keeps running. In the logs I eventually get from STARTING to WILL DO but never observe CANCELLED.

The only thing that indicates some attempt at cancellation is the metadata field on the job which states:

{
  "cancel_attempted_at": "2024-10-02T....."
}

Am I doing something wrong or is there a potential bug?

I am running v0.12.1 and using riverdatabasesql.New, though the underlying connection is pgx, wrapped with opencensus tracing (ocsql).

Reproduce the issue with the SortWorker example, riverui's Cancel action, and riverdatabasesql.New using the described pgx and ocsql setup. Start by tracing cancellation from the cancel_attempted_at metadata to the Work context; done means the worker observes ctx.Done, logs CANCELLED, and stops before the 20-second delay.