fix(#5989): separate picker dedup from restore matching

static/ui.js

@@ -2739,7 +2739,6 @@ function _modelPickerOptionIdentity(modelId){
       ? value.substring(value.lastIndexOf(':')+1)
       : value.substring(value.indexOf(':')+1);
   }
-  value=value.split('/').pop();
   return value.replace(/-/g,'.').toLowerCase();
 }
 function _deduplicateModelPickerOptions(sel,selectedValue){
@@ -2758,8 +2757,7 @@ function _deduplicateModelPickerOptions(sel,selectedValue){
       if(candidates.length<2) continue;
       const selected=candidates.find(opt=>opt.value===selectedValue);
       const routable=candidates.find(opt=>String(opt.value||'').startsWith('@'));
-      const survivor=(selected&&String(selected.value||'').startsWith('@'))
-        || !routable ? (selected||routable||candidates[0]) : routable;
+      const survivor=selected||routable||candidates[0];
       for(const opt of candidates){
         if(opt===survivor) continue;
         group.removeChild(opt);
@@ -3055,11 +3053,14 @@ function _findModelInDropdown(modelId, sel, preferredProviderId){
     const pref=String(preferredProviderId||'').toLowerCase();
     if(!pref || !exactProv || exactProv===pref) return modelId;
   }
-  // 1. Normalize: lowercase, strip namespace prefix, replace hyphens→dots.
-  // Also strip @provider: prefix from deduplicated model IDs (#1228, #1313).
-  const norm=s=>typeof _modelPickerOptionIdentity==='function'
-    ? _modelPickerOptionIdentity(s)
-    : s.toLowerCase().replace(/^[^/]+\//,'').replace(/^@([^:]+:)+/,'').replace(/-/g,'.');
+  // 1. Restore lookup keeps the older hierarchy-preserving matcher instead of
+  // the picker-dedup identity, so missing qualified models do not substitute a
+  // different suffix-sharing sibling.
+  const norm=s=>String(s||'')
+    .toLowerCase()
+    .replace(/^@([^:]+:)+/,'')
+    .replace(/^[^/]+\//,'')
+    .replace(/-/g,'.');
   const target=norm(modelId);
   let explicitProvider='';
   const rawModel=String(modelId||'');

tests/test_issue1228_model_picker_duplicate_ids.py

@@ -262,6 +262,29 @@ console.log(_findModelInDropdown('google/gemma-4-27b', sel, 'custom:beta') || ''
         resolved = subprocess.run(["node", "-e", script], capture_output=True, text=True, check=True)
         assert resolved.stdout.strip() == "@custom:beta:google/gemma-4-27b"
 
+    def test_find_model_returns_no_match_for_missing_qualified_same_suffix_sibling(self):
+        import re
+        import subprocess
+
+        src = self._read_js()
+        helper = re.search(r"function _getOptionProviderId\(opt\)\{.*?\n\}", src, re.S)
+        finder = re.search(r"function _findModelInDropdown\(modelId, sel, preferredProviderId\)\{.*?\n\}", src, re.S)
+        assert helper, "_getOptionProviderId() not found in ui.js"
+        assert finder, "_findModelInDropdown() not found in ui.js"
+
+        script = f"""
+{helper.group(0)}
+{finder.group(0)}
+const sel = {{
+  options: [
+    {{ value: 'vendor-b/catalog/deepseek-v4-pro', parentElement: {{ tagName: 'OPTGROUP', dataset: {{ provider: 'custom:beta' }} }} }},
+  ]
+}};
+console.log(_findModelInDropdown('vendor-a/deepseek-v4-pro', sel, 'custom:alpha') || '');
+"""
+        resolved = subprocess.run(["node", "-e", script], capture_output=True, text=True, check=True)
+        assert resolved.stdout.strip() == ""
+
 
 class TestResolveModelProviderColonInProviderId(unittest.TestCase):
     """resolve_model_provider() must handle provider_ids containing ':'.

tests/test_issue5989_custom_proxy_picker_dedup.py

@@ -79,10 +79,24 @@ const other=new Node('option'); other.value='x-ai/grok-4.5'; otherGroup.appendCh
 const catalogFirst=makeSelect();
 addCatalog(catalogFirst,'x-ai/grok-4.5');
 _addLiveModelsToSelect('custom:llm-proxy',[{{id:'x-ai/grok-4.5',label:'Grok 4.5'}}],catalogFirst);
+const selectedBare=makeSelect();
+addCatalog(selectedBare,'x-ai/grok-4.5');
+selectedBare.value='x-ai/grok-4.5';
+_addLiveModelsToSelect('custom:llm-proxy',[{{id:'x-ai/grok-4.5',label:'Grok 4.5'}}],selectedBare);
+const sameSuffix=makeSelect();
+addCatalog(sameSuffix,'vendor-a/deepseek-v4-pro');
+addCatalog(sameSuffix,'vendor-b/catalog/deepseek-v4-pro');
+sameSuffix.value='vendor-a/deepseek-v4-pro';
 const unnamespaced=makeSelect();
 addCatalog(unnamespaced,'gpt-4o');
 _addLiveModelsToSelect('custom:llm-proxy',[{{id:'@custom:llm-proxy:gpt-4o',label:'GPT-4o'}}],unnamespaced);
-console.log(JSON.stringify({{liveFirst:snapshot(liveFirst),catalogFirst:snapshot(catalogFirst),unnamespaced:snapshot(unnamespaced)}}));
+console.log(JSON.stringify({{
+  liveFirst:snapshot(liveFirst),
+  catalogFirst:snapshot(catalogFirst),
+  selectedBare:snapshot(selectedBare),
+  sameSuffix:snapshot(sameSuffix),
+  unnamespaced:snapshot(unnamespaced),
+}}));
 """
     result = subprocess.run(["node", "-e", script], capture_output=True, text=True)
     assert result.returncode == 0, result.stderr
@@ -104,6 +118,20 @@ def test_catalog_first_keeps_the_routable_proxy_row():
     }
 
 
+def test_selected_bare_occurrence_survives_same_group_dedup():
+    assert _run_harness()["selectedBare"] == {
+        "groups": [["x-ai/grok-4.5"]],
+        "selected": "x-ai/grok-4.5",
+    }
+
+
+def test_same_suffix_models_in_one_group_do_not_collapse():
+    assert _run_harness()["sameSuffix"] == {
+        "groups": [["vendor-a/deepseek-v4-pro", "vendor-b/catalog/deepseek-v4-pro"]],
+        "selected": "vendor-a/deepseek-v4-pro",
+    }
+
+
 def test_unnamespaced_custom_proxy_value_deduplicates_with_catalog():
     assert _run_harness()["unnamespaced"] == {
         "groups": [["@custom:llm-proxy:gpt-4o"]],