[FIX] web: Allow users to enable list view with group_by_no_leaf

- Go to accounting/Report/Invoices Analysis
- Open studio
- enable list view
- empty view

This code bellow compute count_field as `__count` because group_by_no_leaf
is in the context.

But in the basic_model we don't consider this case.

https://github.com/odoo/odoo/blob/5797fd80a63309269f15bcbe4948d4429a53eec2/odoo/models.py#L2798-L2802

opw-2980923

closes odoo/odoo#101570

X-original-commit: bde2985959ef8914da4b8aca96efc5772262d0c0
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>

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

@@ -2401,6 +2401,10 @@ export class DynamicGroupList extends DynamicList {
                         }
                         break;
                     }
+                    // When group_by_no_leaf key is present FIELD_ID_count doesn't exist
+                    // we have to get the count from `__count` instead
+                    // see _read_group_raw in models.py
+                    case `__count`:
                     case `${groupByField.name}_count`: {
                         groupParams.count = value;
                         break;

addons/web/static/tests/helpers/mock_server.js

@@ -1095,7 +1095,13 @@ export class MockServer {
                 delete group.__range;
             }
             // compute count key to match dumb server logic...
-            const countKey = kwargs.lazy ? groupBy[0].split(":")[0] + "_count" : "__count";
+            const groupByNoLeaf = kwargs.context ? "group_by_no_leaf" in kwargs.context : false;
+            let countKey;
+            if (kwargs.lazy && (groupBy.length >= 2 || !groupByNoLeaf)) {
+                countKey = groupBy[0].split(":")[0] + "_count";
+            } else {
+                countKey = "__count";
+            }
             group[countKey] = groupRecords.length;
             aggregateFields(group, groupRecords);
             readGroupResult.push(group);

addons/web/static/tests/views/list_view_tests.js

@@ -15151,4 +15151,28 @@ QUnit.module("Views", (hooks) => {
         await pagerPrevious(target);
         assert.deepEqual([...getPagerValue(target), getPagerLimit(target)], [1, 2]);
     });
+
+    QUnit.test("list with group_by_no_leaf and group by", async function (assert) {
+        assert.expect(4);
+
+        await makeView({
+            type: "list",
+            resModel: "foo",
+            serverData,
+            arch: '<tree expand="1"><field name="foo"/></tree>',
+            groupBy: ["currency_id"],
+            context: { group_by_no_leaf: true },
+        });
+
+        const groups = target.querySelectorAll(".o_group_name");
+        const groupsRecords = [...target.querySelectorAll(".o_data_row .o_data_cell")];
+        assert.strictEqual(groups.length, 2, "There should be 2 groups");
+        assert.strictEqual(groups[0].textContent, "USD (3) ", "Second group should have 3 records");
+        assert.strictEqual(groups[1].textContent, "EUR (1) ", "First group should have 1 record");
+        assert.deepEqual(
+            groupsRecords.map((groupEl) => groupEl.textContent),
+            ["blip", "gnap", "blip", "yop"],
+            "Groups should contains correct records"
+        );
+    });
 });