REVIVE button silently no-ops when resuming a run with no hyperparams in /api/status

[mmoalem]

REVIVE button silently no-ops when resuming a run with no hyperparams in /api/status

Symptom

After restoring a session from an external backup (e.g. HF Hub sync, as the Kaggle notebook setup does), clicking REVIVE on a killed/error/completed run does nothing — no modal opens, no network request fires, no visible error. The button itself is enabled (has_restart_cmd is true) and onclick="openResumeModal()" is correctly wired, but the handler throws before reaching classList.add('active').

Browser console shows:

Uncaught TypeError: Cannot read properties of undefined (reading 'length')
    at window.openResumeModal (index.html:4507)

Root cause

dashboard/index.html has 8 call sites of this shape:

const info = _modelSeqInfo[someKey] || _modelSeqInfo['sa3'];
// ... info.length used unconditionally right after

The hardcoded 'sa3' fallback assumes every deployment registers a model under the literal key 'sa3'. That's not true for deployments that only register versioned/qualified model names (in my case: sa3-medium, sa3-sm-music, sa3-sm-sfx — no plain sa3).

This only bites when the primary key lookup also misses. That happens in openResumeModal() specifically because _currentStatus.hyperparams can be entirely absent: _get_status() in dashboard/server.py returns an early stub response ({"running": false, "status": ..., "message": "Log file not found", "has_restart_cmd": ...}) whenever run["log_path"] doesn't exist on disk — which is the normal case after restoring run state from an external backup, since .log files aren't part of any state that gets backed up/restored (only .safetensors/.json are, per typical sync setups). With hyperparams missing, hp.base_model is undefined, the primary lookup misses, and the 'sa3' fallback also misses → _modelSeqInfo[...] is undefined → .length throws.

Repro

1. Train a run, register a model under a key other than exactly sa3 (e.g. sa3-medium).
2. Lose/delete the run's log file on disk (or restore runs.json + checkpoints from a backup without the .log file — anything that makes Path(run["log_path"]).exists() false).
3. Restart the dashboard server; the run shows status killed/error with a REVIVE button.
4. Click REVIVE.

Expected: resume modal opens.
Actual: nothing happens; console shows the TypeError above.

Fix

Replace the hardcoded 'sa3' fallback with a small helper that falls back to 'sa3' if present, then to whatever model is registered first — so the lookup can never resolve to undefined as long as at least one model is registered:

function _seqInfoFor(key) {
  return _modelSeqInfo[key] || _modelSeqInfo['sa3'] || _modelSeqInfo[Object.keys(_modelSeqInfo)[0]];
}

...and point all 8 _modelSeqInfo[x] || _modelSeqInfo['sa3'] call sites at it. Patch attached (fix.patch, applies cleanly to dashboard/index.html at 06b61cb). Tested: reproduces the exact throw on the old code path, confirmed resolved on the patched path, normal case (hyperparams present, valid base_model) unaffected.

Happy to open this as a PR directly if preferred — let me know.