[FIX] web: reset expanded fields on import compatibility switch

Steps to reproduce
==================

- Go to users
- Open the export dialog
- Expand the Groups field
- Add the Groups > Groups/Access Controls field
- Check the import compatibility option
- Expand the Groups field again
=> `TypeError: this.knownFields[id] is undefined`

Solution
========

The expandedFields were not reset. We also need to update the t-key to
take the compatibility state into account.

opw-3378834

closes odoo/odoo#146116

X-original-commit: d2f52abb8ce1b7e5291e0de7d4ea7788f39115bd
Signed-off-by: Luca Vitali (luvi) <luvi@odoo.com>

addons/web/static/src/views/view_dialogs/export_data_dialog.js

@@ -204,6 +204,7 @@ export class ExportDataDialog extends Component {
     async fetchFields() {
         this.state.search = [];
         this.knownFields = {};
+        this.expandedFields = {};
         await this.loadFields();
         await this.setDefaultExportList();
         if (this.searchRef.el) {

addons/web/static/src/views/view_dialogs/export_data_dialog.xml

@@ -42,7 +42,7 @@
                     <div class="o_left_field_panel h-100 overflow-auto border">
                         <div class="o_field_tree_structure">
                             <t t-if="fieldsAvailable">
-                                <t t-foreach="rootFields" t-as="field" t-key="field.id + '_' + state.search.length">
+                                <t t-foreach="rootFields" t-as="field" t-key="field.id + '_' + state.search.length + '_' + state.isCompatible">
                                     <ExportDataItem
                                         exportList="state.exportList"
                                         field="field"

addons/web/static/tests/views/view_dialogs/export_data_dialog_tests.js

@@ -647,6 +647,46 @@ QUnit.module("ViewDialogs", (hooks) => {
         await click(target, ".o_select_button");
     });
 
+    QUnit.test("toggling import compatibility after adding an expanded field", async function (assert) {
+        assert.expect(1);
+
+        mockDownload(({ url, data }) => {
+            assert.ok(
+                JSON.parse(data.data)["import_compat"],
+                "request to generate the file must have 'import_compat' as true"
+            );
+            return Promise.resolve();
+        });
+
+        await makeView({
+            serverData,
+            type: "list",
+            resModel: "partner",
+            arch: `<tree><field name="foo"/></tree>`,
+            actionMenus: {},
+            mockRPC(route, args) {
+                if (route === "/web/export/formats") {
+                    return Promise.resolve([
+                        { tag: "csv", label: "CSV" },
+                    ]);
+                }
+                if (route === "/web/export/get_fields") {
+                    if (!args.parent_field) {
+                        return Promise.resolve(fetchedFields.root);
+                    }
+                    return Promise.resolve(fetchedFields[args.prefix]);
+                }
+            },
+        });
+
+        await openExportDataDialog();
+        await click(target, "[data-field_id='activity_ids']");
+        await click(target, "[data-field_id='activity_ids/partner_ids'] .o_add_field");
+        await click(target, ".o_import_compat input");
+        await click(target, "[data-field_id='activity_ids']");
+        await click(target, ".o_select_button");
+    });
+
     QUnit.test("Export dialog: many2many fields are extendable", async function (assert) {
         await makeView({
             serverData,