[FIX] web: fix the Reference field in list view with a default value

Bug
===
If the Reference field is in a list view, and has a default value, an
error is raised if we create a new record without editing the reference
value. This is because the ORM return a string "model,id" in the
onchange method and this value is wrongly parsed in that case.

Task-2234179

closes odoo/odoo#113392

X-original-commit: b1a35d1b95612bc449b68ed38749d8b3755287ed
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>
Signed-off-by: Stéphane Debauche (std) <std@odoo.com>

addons/web/static/src/views/relational_model.js

@@ -724,7 +724,9 @@ export class Record extends DataPoint {
                     : false;
             } else if (fieldType === "reference") {
                 const value = changes[fieldName];
-                changes[fieldName] = value ? `${value.resModel},${value.resId}` : false;
+                changes[fieldName] = value && value.resModel && value.resId
+                    ? `${value.resModel},${value.resId}`
+                    : (value || false);
             }
         }
 

addons/web/static/tests/views/fields/reference_field_tests.js

@@ -845,6 +845,36 @@ QUnit.module("Fields", (hooks) => {
         }
     );
 
+    QUnit.test("Reference field with default value in list view", async function (assert) {
+        assert.expect(2);
+
+        await makeView({
+            type: "list",
+            resModel: "partner",
+            serverData,
+            arch: `
+                <tree string="Test" editable="top">
+                    <field name="reference"/>
+                    <field name="display_name"/>
+                </tree>`,
+            mockRPC: (route, { method, args }) => {
+                if (method === "onchange") {
+                    return {
+                        value: {reference: "partner,2"},
+                    };
+                } else if (method === "create") {
+                    assert.strictEqual(args.length, 1);
+                    assert.strictEqual(args[0][0].reference, "partner,2");
+                }
+            },
+        });
+
+        await click(target, '.o_list_button_add');
+        await click(target, '.o_list_char[name="display_name"] input');
+        await editInput(target, '.o_list_char[name="display_name"] input', "Blabla");
+        await click(target, '.o_list_button_save');
+    });
+
     QUnit.test(
         "ReferenceField with model_field option (tree list in form view)",
         async function (assert) {