fix: model persistence for all scenarios (#21051)

packages/core/src/config/config.test.ts

@@ -2198,6 +2198,23 @@ describe('Config getHooks', () => {
 
       expect(onModelChange).not.toHaveBeenCalled();
     });
+
+    it('should call onModelChange when persisting a model that was previously temporary', () => {
+      const onModelChange = vi.fn();
+      const config = new Config({
+        ...baseParams,
+        model: 'some-other-model',
+        onModelChange,
+      });
+
+      // Temporary selection
+      config.setModel(DEFAULT_GEMINI_MODEL, true);
+      expect(onModelChange).not.toHaveBeenCalled();
+
+      // Persist selection of the same model
+      config.setModel(DEFAULT_GEMINI_MODEL, false);
+      expect(onModelChange).toHaveBeenCalledWith(DEFAULT_GEMINI_MODEL);
+    });
   });
 });
 

packages/core/src/config/config.ts

@@ -1403,9 +1403,9 @@ export class Config implements McpContext {
       // When the user explicitly sets a model, that becomes the active model.
       this._activeModel = newModel;
       coreEvents.emitModelChanged(newModel);
-      if (this.onModelChange && !isTemporary) {
-        this.onModelChange(newModel);
-      }
+    }
+    if (this.onModelChange && !isTemporary) {
+      this.onModelChange(newModel);
     }
     this.modelAvailabilityService.reset();
   }