Keep the file picker's account when the source type changes

The reset ran in an effect after the new picker had reported its default
account, so remote uploads could send no connection. It now happens with
the type change. A connection tile that is not set up says Not connected.

frontend/src/upload/Upload.test.tsx

@@ -43,6 +43,25 @@ vi.mock('../connectors/useConnectorLauncher', () => ({
   default: () => ({ launch, modals: null }),
 }));
 
+// The file picker reports its default account and a pick as it mounts.
+vi.mock('../components/FilePicker', async () => {
+  const { useEffect } = await import('react');
+  return {
+    FilePicker: function Picker(props: {
+      onConnectionChange: (id: string | null) => void;
+      onSelectionChange: (files: string[], folders?: string[]) => void;
+      onFirstPickName: (name: string) => void;
+    }) {
+      useEffect(() => {
+        props.onConnectionChange('drive-1');
+        props.onSelectionChange(['file-1'], []);
+        props.onFirstPickName('Handbook');
+      }, []);
+      return null;
+    },
+  };
+});
+
 import Upload from './Upload';
 
 Object.assign(globalThis, { IS_REACT_ACT_ENVIRONMENT: true });
@@ -265,6 +284,52 @@ describe('Upload source-type tiles', () => {
     connectorsState.connections = [];
   });
 
+  it("sends the picker's account, not one cleared by the type change", async () => {
+    connectorsState.catalog = [
+      {
+        key: 'google_drive',
+        icon: 'drive',
+        sync_ingestor: 'google_drive',
+        auth_kind: 'oauth',
+        available: true,
+        missing_settings: [],
+      },
+    ];
+    const sent: FormData[] = [];
+    class FakeXhr {
+      upload = { addEventListener() {} };
+      addEventListener() {}
+      open() {}
+      setRequestHeader() {}
+      send(body: FormData) {
+        sent.push(body);
+      }
+    }
+    vi.stubGlobal('XMLHttpRequest', FakeXhr);
+    await act(async () =>
+      root.render(
+        <Upload
+          receivedFile={[]}
+          setModalState={vi.fn()}
+          isOnboarding={false}
+          renderTab={null}
+          close={vi.fn()}
+          initialIngestor="google_drive"
+        />,
+      ),
+    );
+    const train = Array.from(document.body.querySelectorAll('button')).find(
+      (b) => b.textContent === 'modals.uploadDoc.train',
+    )!;
+    await act(async () => train.click());
+    expect(sent).toHaveLength(1);
+    expect(JSON.parse(String(sent[0].get('data'))).connection_id).toBe(
+      'drive-1',
+    );
+    vi.unstubAllGlobals();
+    connectorsState.catalog = [];
+  });
+
   it('leaves the disabled Train button on the default variant', async () => {
     await render();
     const crawler = tiles().find((tile) =>

frontend/src/upload/Upload.tsx

@@ -556,10 +556,6 @@ function Upload({
   // user made in the account picker.
   const accountPicked = useRef(false);
   const firstKeyAccount = keyAccounts[0]?.id;
-  useEffect(() => {
-    accountPicked.current = false;
-    setConnectionId(null);
-  }, [ingestor.type]);
   useEffect(() => {
     if (selectedConnector?.auth_kind !== 'api_key' || accountPicked.current)
       return;
@@ -1159,6 +1155,11 @@ function Upload({
     }));
   };
   const handleIngestorTypeChange = (type: IngestorType | null) => {
+    // The account resets with the type, here rather than in an effect: the
+    // new type's picker reports its default account as it mounts, and an
+    // effect would run after that and clear it.
+    accountPicked.current = false;
+    setConnectionId(null);
     if (type === null) {
       setIngestor({
         type: null,
@@ -1204,7 +1205,8 @@ function Upload({
         count: accounts.length,
         formatted: formatCount(accounts.length),
       });
-    return t('settings.connectors.status.connect');
+    // A status, not a button: the tile itself starts the connection.
+    return t('modals.uploadDoc.tileNotConnected');
   };
 
   // With the catalog loaded, members only see connections they can use: