Stage 372: PR #2411 — fix: preserve named custom provider model selections by @Michaelyklam (fixes #2405)

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - **PR #2406** by @Michaelyklam (fixes #2398) — The fallback synchronous `POST /api/chat` route now passes the active WebUI config into the conversation-history sanitizer, so text-mode providers do not receive historical native `image_url` content parts when direct API callers use the legacy chat endpoint. This brings the sync route in line with the streaming chat path fixed for #2297.
 - **PR #2408** by @Michaelyklam (fixes #2404) — Auto-compression cards now close the current live Activity burst before rendering, so post-compression tools start a fresh `Activity` row instead of joining the pre-compression tool group across a real timeline/context boundary.
+- **PR #2411** by @Michaelyklam (fixes #2405) — Named `custom:*` providers no longer lose vendor-prefixed model selections when the static model picker has not hydrated that model yet. The frontend now treats named custom providers as routable aggregators for both mismatch-warning suppression and missing-dropdown fallback, and live-fetched models keep explicit `@custom:name:` provider context so selections persist instead of snapping back to the configured default.
 
 ### Documentation
 

static/ui.js

@@ -729,6 +729,18 @@ function _providerFromModelValue(modelId){
   if(value.startsWith('@')&&value.includes(':')) return value.slice(1,value.lastIndexOf(':'));
   return '';
 }
+function _providerSkipsModelMismatchWarning(providerId){
+  const p=String(providerId||'').toLowerCase();
+  return !p||p==='custom'||p.startsWith('custom:')||p==='openrouter';
+}
+function _providerDefersMissingModelFallback(providerId){
+  const p=String(providerId||'').toLowerCase();
+  // Named custom providers and OpenRouter can legitimately route vendor-prefixed
+  // model IDs that are not present in the current static catalog. Do not
+  // silently rewrite those sessions to the default just because the option has
+  // not been hydrated yet (#2405).
+  return p.startsWith('custom:')||p==='openrouter';
+}
 function _modelStateForSelect(sel, modelId){
   const value=String(modelId||'').trim();
   if(!value) return {model:'',model_provider:null};
@@ -990,21 +1002,20 @@ function _addLiveModelsToSelect(provider, models, sel){
     sel.appendChild(providerGroup);
   }
   const existingIds=new Set([...sel.options].map(o=>o.value));
-  // Normalized dedup: strip @provider: prefix and unify separators so
+  // Normalized dedup: strip one @provider: prefix and namespace so
   // 'minimax/minimax-m2.7' matches '@nous:minimax/minimax-m2.7' (#907).
-  // Strip ONLY the first colon — Ollama tag IDs are multi-colon
-  // (e.g. '@ollama-cloud:qwen3-vl:235b-instruct') and split(':',2) would
-  // truncate the tag suffix in JS (the limit arg discards extras, unlike Python).
   const _normId=id=>{
     let s=String(id||'');
-    if(s.startsWith('@')&&s.includes(':')) s=s.substring(s.indexOf(':')+1); // strip only @provider:
-    s=s.split('/').pop();                                                    // strip namespace prefix
+    if(s.startsWith('@')&&s.includes(':')) s=s.substring(s.indexOf(':')+1);
+    s=s.split('/').pop();
     return s.replace(/-/g,'.').toLowerCase();
   };
   const existingNorm=new Set([...sel.options].map(o=>_normId(o.value)));
   let added=0;
   const _ap=(window._activeProvider||'').toLowerCase();
-  const _isPortalFetch=_ap && _ap!=='openrouter' && _ap!=='custom' && _ap!=='openai-codex' && provider===_ap;
+  const _providerLower=String(provider||'').toLowerCase();
+  const _isNamedCustomActiveProvider=_ap.startsWith('custom:');
+  const _isPortalFetch=_ap && _ap!=='openrouter' && _ap!=='custom' && _ap!=='openai-codex' && (_providerLower===_ap||_isNamedCustomActiveProvider&&_providerLower===_ap);
   for(const m of models){
     let mid=m.id;
     if(_isPortalFetch && !mid.startsWith('@')){
@@ -1075,7 +1086,7 @@ async function _fetchLiveModels(provider, sel){
  */
 function _checkProviderMismatch(modelId){
   const ap=(window._activeProvider||'').toLowerCase();
-  if(!ap||ap==='custom'||ap.startsWith('custom:')||ap==='openrouter') return null; // can't reliably check
+  if(_providerSkipsModelMismatchWarning(ap)) return null; // can't reliably check
   // @provider: prefixed IDs came from that provider's live model list — no mismatch possible
   if(modelId.startsWith('@')) return null;
   const slash=modelId.indexOf('/');
@@ -4574,13 +4585,16 @@ function syncTopbar(){
       // default rather than silently retaining the previous chat's selection (#1771).
       if(!applied){
         const deferModelCorrection=Boolean(S.session._modelResolutionDeferred);
+        const missingModelIsRoutable=_providerDefersMissingModelFallback(S.session.model_provider||window._activeProvider||null);
         // Also defer if a live model fetch is still in flight — the model may be
         // in the list once the fetch completes. Persisting now would corrupt the
         // session with the wrong model before live models arrive (#1169).
         const liveStillPending=window._activeProvider&&_liveModelFetchPending.has(window._activeProvider);
-        if(liveStillPending){
+        if(liveStillPending||missingModelIsRoutable){
           // Live fetch in flight — don't touch sel.value or S.session.model yet.
           // _addLiveModelsToSelect() will re-apply S.session.model once done (#1169).
+          // Named custom providers/OpenRouter can also route vendor-prefixed IDs
+          // outside the static catalog, so preserve the user's explicit choice.
         } else {
           const fallback=_applySessionModelFallback(modelSel);
           if(fallback&&!deferModelCorrection){

tests/test_provider_mismatch.py

@@ -128,27 +128,43 @@ class TestCheckProviderMismatch:
         src = _read("static/ui.js")
         idx = src.find("function _checkProviderMismatch")
         block = src[idx:idx + 800]
-        assert "openrouter" in block.lower(), (
+        assert "_providerSkipsModelMismatchWarning(ap)" in block, (
             "_checkProviderMismatch must skip the check for openrouter"
         )
+        helper_idx = src.find("function _providerSkipsModelMismatchWarning")
+        helper = src[helper_idx:helper_idx + 350]
+        assert "openrouter" in helper.lower(), (
+            "_providerSkipsModelMismatchWarning must skip OpenRouter"
+        )
 
     def test_skips_check_for_custom(self):
         """Custom endpoints can serve any model — skip the warning."""
         src = _read("static/ui.js")
         idx = src.find("function _checkProviderMismatch")
         block = src[idx:idx + 800]
-        assert "custom" in block.lower(), (
+        assert "_providerSkipsModelMismatchWarning(ap)" in block, (
             "_checkProviderMismatch must skip the check for custom provider"
         )
+        helper_idx = src.find("function _providerSkipsModelMismatchWarning")
+        helper = src[helper_idx:helper_idx + 350]
+        assert "p==='custom'" in helper, (
+            "_providerSkipsModelMismatchWarning must skip bare custom providers"
+        )
 
     def test_skips_check_for_named_custom_provider(self):
         """Named custom providers are aggregators too — skip the warning."""
         src = _read("static/ui.js")
         idx = src.find("function _checkProviderMismatch")
         block = src[idx:idx + 800]
-        assert "startsWith('custom:')" in block, (
+        assert "_providerSkipsModelMismatchWarning(ap)" in block, (
             "_checkProviderMismatch must skip named custom providers like custom:zenmux"
         )
+        helper_idx = src.find("function _providerSkipsModelMismatchWarning")
+        assert helper_idx != -1, "named custom provider skip helper must exist"
+        helper = src[helper_idx:helper_idx + 350]
+        assert "p.startsWith('custom:')" in helper, (
+            "named custom providers must be treated like custom aggregators"
+        )
 
     def test_active_provider_stored_on_model_load(self):
         """populateModelDropdown must store active_provider from /api/models."""
@@ -1167,6 +1183,37 @@ class TestFrontendModelProviderState:
         assert "_providerQualifiedModelValueForSelect(sel, modelId)" in src
         assert "return _modelStateForSelect(sel,modelId).model" in src
 
+    def test_named_custom_live_models_keep_provider_prefix(self):
+        """Live models from custom:* providers should keep explicit provider context."""
+        src = _read("static/ui.js")
+        idx = src.find("function _addLiveModelsToSelect")
+        assert idx != -1, "_addLiveModelsToSelect must exist"
+        block = src[idx:idx + 2200]
+        assert "_isNamedCustomActiveProvider=_ap.startsWith('custom:')" in block, (
+            "named custom providers must be recognized during live model hydration"
+        )
+        assert "_providerLower=String(provider||'').toLowerCase()" in block
+        assert "_providerLower===_ap||_isNamedCustomActiveProvider&&_providerLower===_ap" in block, (
+            "custom:* live model fetches must qualify added model IDs with @custom:name:"
+        )
+
+    def test_named_custom_missing_dropdown_model_does_not_persist_fallback(self):
+        """syncTopbar must not overwrite custom:* selections just because the static picker lacks them."""
+        src = _read("static/ui.js")
+        helper_idx = src.find("function _providerDefersMissingModelFallback")
+        assert helper_idx != -1, "custom-provider missing-model fallback helper must exist"
+        helper = src[helper_idx:helper_idx + 500]
+        assert "p.startsWith('custom:')" in helper, (
+            "named custom providers can route vendor-prefixed models outside the static catalog"
+        )
+        idx = src.find("function syncTopbar")
+        assert idx != -1, "syncTopbar must exist"
+        block = src[idx:idx + 5200]
+        assert "missingModelIsRoutable=_providerDefersMissingModelFallback" in block
+        assert "liveStillPending||missingModelIsRoutable" in block, (
+            "syncTopbar must preserve routable custom:* selections instead of forcing fallback persistence"
+        )
+
 
 def test_unknown_prefix_model_passes_through_unchanged(monkeypatch):
     """Models with unknown/custom prefixes must never be stripped — regression test for #751."""