fix semantic search model_size showing dirty for genai embeddings providers

The resolved config always reports model_size (schema default), so clearing it
whenever a provider was selected falsely marked the field dirty on load and sent
a delete for a YAML key that isn't there (Error updating config: 'model_size').
Only clear a non-default value, which is the only case actually present in the
config file.

web/e2e/specs/settings/semantic-search.spec.ts

@@ -0,0 +1,129 @@
+/**
+ * Semantic Search settings tests -- MEDIUM tier.
+ *
+ * Focuses on the model_size field, which is unused when a GenAI embeddings
+ * provider is selected as the semantic search model. The resolved config always
+ * reports model_size (it has a schema default of "small"), even when the YAML
+ * file has no such key. Clearing model_size for a provider used to run
+ * unconditionally, which falsely marked the section dirty on load and asked the
+ * backend to delete a key that wasn't in the config file (KeyError: 'model_size').
+ */
+
+import { readFileSync } from "node:fs";
+import { resolve, dirname } from "node:path";
+import { fileURLToPath } from "node:url";
+import { test, expect } from "../../fixtures/frigate-test";
+import type { Page } from "@playwright/test";
+import { configFactory } from "../../fixtures/mock-data/config";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const CONFIG_SCHEMA = JSON.parse(
+  readFileSync(
+    resolve(__dirname, "../../fixtures/mock-data/config-schema.json"),
+    "utf-8",
+  ),
+);
+
+const PROVIDER = "llama_cpp";
+const SETTINGS_URL = "/settings?page=integrationSemanticSearch";
+const NOT_APPLICABLE = "Not applicable for GenAI providers";
+const UNSAVED = "You have unsaved changes";
+
+type SemanticSearch = {
+  enabled?: boolean;
+  model?: string;
+  model_size?: string;
+};
+
+async function installRoutes(page: Page, semanticSearch: SemanticSearch) {
+  const config = configFactory({
+    genai: { [PROVIDER]: { provider: PROVIDER, roles: ["embeddings"] } },
+    semantic_search: semanticSearch,
+  });
+
+  let lastSavedConfig: unknown = null;
+
+  await page.route("**/api/config/schema.json", (route) =>
+    route.fulfill({ json: CONFIG_SCHEMA }),
+  );
+  await page.route("**/api/config", (route) => {
+    if (route.request().method() === "GET") {
+      return route.fulfill({ json: config });
+    }
+    return route.fulfill({ json: { success: true } });
+  });
+  await page.route("**/api/config/set", async (route) => {
+    lastSavedConfig = route.request().postDataJSON();
+    await route.fulfill({ json: { success: true, require_restart: false } });
+  });
+  await page.route("**/api/config/raw_paths", (route) =>
+    route.fulfill({ json: { semantic_search: semanticSearch } }),
+  );
+
+  return { capturedConfig: () => lastSavedConfig };
+}
+
+test.describe("semantic search model_size @medium", () => {
+  test("a provider with a defaulted model_size is not dirty on load", async ({
+    frigateApp,
+  }) => {
+    // model_size stays at its schema default ("small"), i.e. it is not present
+    // in the YAML. This mirrors the reported bug: selecting a GenAI provider and
+    // returning to the page.
+    await installRoutes(frigateApp.page, {
+      enabled: true,
+      model: PROVIDER,
+    });
+    await frigateApp.goto(SETTINGS_URL);
+
+    // The provider path is active: model_size shows "Not applicable".
+    await expect(frigateApp.page.getByText(NOT_APPLICABLE)).toBeVisible();
+
+    // Give any clearing effect time to fire, then confirm the section stayed
+    // clean (no phantom unsaved-changes banner, Save disabled).
+    await frigateApp.page.waitForTimeout(1000);
+    await expect(frigateApp.page.getByText(UNSAVED)).toBeHidden();
+    await expect(
+      frigateApp.page.getByRole("button", { name: "Save", exact: true }),
+    ).toBeDisabled();
+  });
+
+  test("switching from a configured non-default model_size clears it", async ({
+    frigateApp,
+  }) => {
+    // A genuinely configured non-default model_size ("large") can only come from
+    // the YAML, so switching to a provider must still remove it.
+    const capture = await installRoutes(frigateApp.page, {
+      enabled: true,
+      model: "jinav2",
+      model_size: "large",
+    });
+    await frigateApp.goto(SETTINGS_URL);
+
+    // Starts clean on a Jina model.
+    await expect(frigateApp.page.getByText(UNSAVED)).toBeHidden();
+
+    // Switch the model to the GenAI provider.
+    await frigateApp.page
+      .getByRole("combobox", { name: /Semantic search model/ })
+      .click();
+    await frigateApp.page.getByRole("option", { name: PROVIDER }).click();
+
+    // The change is now dirty and model_size is no longer applicable.
+    await expect(frigateApp.page.getByText(NOT_APPLICABLE)).toBeVisible();
+    await expect(frigateApp.page.getByText(UNSAVED)).toBeVisible();
+
+    await frigateApp.page
+      .getByRole("button", { name: "Save", exact: true })
+      .click();
+
+    // The saved payload removes model_size (empty string = "remove" key).
+    await expect
+      .poll(() => capture.capturedConfig(), { timeout: 5_000 })
+      .toMatchObject({
+        config_data: {
+          semantic_search: { model: PROVIDER, model_size: "" },
+        },
+      });
+  });
+});

web/src/components/config-form/theme/widgets/SemanticSearchModelSizeWidget.tsx

@@ -24,15 +24,19 @@ export function SemanticSearchModelSizeWidget(props: WidgetProps) {
     model !== "jinav1" &&
     model !== "jinav2";
 
-  // Clear model_size while on a provider (buildOverrides converts to ""
-  // which the backend treats as "remove"). Restore the schema default
-  // when returning to a Jina model so the field isn't left empty.
+  // model_size is unused on a GenAI provider. Only clear it (which the backend
+  // treats as "remove") for a non-default value, which can only come from the
+  // config file. A defaulted value is indistinguishable from unset in the
+  // resolved config, so clearing it would falsely dirty the field and delete a
+  // YAML key that isn't there. Restore the default when returning to a Jina model.
   const { value, onChange, schema } = props;
   const schemaDefault = schema?.default as string | undefined;
   useEffect(() => {
-    if (isProvider && value !== undefined) {
-      onChange(undefined);
-    } else if (!isProvider && value === undefined && schemaDefault) {
+    if (isProvider) {
+      if (value !== undefined && value !== schemaDefault) {
+        onChange(undefined);
+      }
+    } else if (value === undefined && schemaDefault) {
       onChange(schemaDefault);
     }
   }, [isProvider, value, onChange, schemaDefault]);