fix: guard localStorage.setItem('hermes-webui-model') against QuotaExceededError

[24601]

Problem

On some setups (localStorage near quota), the bare localStorage.setItem('hermes-webui-model', ...) call throws an unhandled DOMException:

Failed to execute 'setItem' on 'Storage': Setting the value of 'hermes-webui-model' exceeded the quota.

This surfaces as a fatal exception that breaks model selection and prevents the chat UI from loading on every new chat or page load.

Fix

Wrap both call-sites in try/catch so the error is logged to the console as a console.warn instead of crashing the UI. The stored value (a model ID string) is tiny — the quota failure is from overall localStorage pressure, not this key — so graceful degradation (fall back to server-side model state on next load) is the right behaviour.

Files changed:

• static/boot.js — $('modelSelect').onchange handler
• static/onboarding.js — _saveOnboardingDefaults()

Test

1. Fill localStorage to near-quota in DevTools
2. Change model in the selector → no thrown exception, console shows warning
3. Reload → UI loads normally

[nesquena-hermes]

Thanks for the report and the patch — the QuotaExceededError on localStorage.setItem('hermes-webui-model', ...) is real, and graceful degradation is the right call. But after reading the diff against static/boot.js:815 and static/onboarding.js:468, then walking the actual call sites that touch this key, I think this PR misses the two most likely places the error actually fires from. As-is it's almost a no-op.

What's already wrapped vs what's not

The canonical write helper is _writePersistedModelState() in static/ui.js:457-469:

function _writePersistedModelState(model, modelProvider){
  const value=String(model||'').trim();
  ...
  localStorage.setItem('hermes-webui-model', value);          // line 465 — UNGUARDED
  try{
    localStorage.setItem(MODEL_STATE_KEY, JSON.stringify({model:value,model_provider:provider||null}));
  }catch(_){}
}

Whoever wrote this wrapped the second setItem (the JSON MODEL_STATE_KEY write, which is large and the actual quota risk) but not the first. Under quota pressure, line 465 is what throws. Every other module in the codebase routes through this helper, so wrapping callers without wrapping the helper itself doesn't help.

Why the boot.js change is effectively dead code

The patched line is the else branch:

if(typeof _writePersistedModelState==='function') _writePersistedModelState(modelState.model,modelState.model_provider);
else try{localStorage.setItem('hermes-webui-model',modelState.model)}catch{}

_writePersistedModelState is defined in static/ui.js, which is loaded before static/boot.js in the bundle. The typeof === 'function' branch is always taken in practice; the else fallback only existed for paranoia. Guarding the fallback while leaving the helper unguarded means the actual flow still throws.

The other unguarded site the PR misses

static/messages.js:233 writes the same key during stream start:

if(startData.effective_model && S.session){
  S.session.model=startData.effective_model;
  ...
  localStorage.setItem('hermes-webui-model', startData.effective_model);   // unguarded
  if(typeof _writePersistedModelState==='function') _writePersistedModelState(...);

This fires on every send when the gateway resolves a different effective model — which on near-quota setups is going to throw before the onboarding/onchange paths even get a chance.

Suggested fix

Push the try/catch one level down into the helper, then drop the now-redundant outer wraps:

// static/ui.js:465
try{ localStorage.setItem('hermes-webui-model', value); }catch(_){}

And add the same guard at static/messages.js:233. The onboarding.js wrap you already added stays useful (that path runs before _writePersistedModelState exists during first-boot wizard, in some load orders), so keep that one. The boot.js change can revert since the else branch is unreachable.

Verification

• DevTools → Application → Local Storage, fill to quota with a junk key
• Send a message that the gateway re-resolves to a different model → check messages.js:233 no longer throws
• Change model in selector → _writePersistedModelState no longer throws
• Reload, run onboarding → still wraps correctly

CI passing here just means the existing tests don't cover quota-exceeded paths (none do). A unit test would need a localStorage stub that throws on setItem; happy to point at where to add one if you want to extend the patch.

[nesquena-hermes]

Closed by the v0.51.5 release in PR #1713 (merged at 0ea3dfb, deployed to production). Thanks!

Live on production: https://github.com/nesquena/hermes-webui/releases/tag/v0.51.5

🚀