[FIX] web: FormStatusIndicator flickering

Purpose:
--------
Before this commit, if you edit a char field with an onchange in
an x2many, the FormStatusIndicator buttons will flicker.

How to reproduce:
-----------------
- Go to a form view with an x2many field in list mode
- Type a char in the char field of a record
- The FormStatusIndicator buttons are visible
- Click outside the char field
- An onchange is triggered

Before this commit:
    The FormStatusIndicator buttons will disappear until the onchange returns.

After this commit:
    The FormStatusIndicator buttons remain visible.

closes odoo/odoo#140179

Signed-off-by: Pierre Rousseau (pro) <pro@odoo.com>

addons/web/static/src/views/fields/input_field_hook.js

@@ -53,7 +53,7 @@ export function useInputField(params) {
      * On blur, we consider the field no longer dirty, even if it were to be invalid.
      * However, if the field is invalid, the new value will not be committed to the model.
      */
-    function onChange(ev) {
+    async function onChange(ev) {
         if (isDirty) {
             isDirty = false;
             let isInvalid = false;
@@ -69,15 +69,12 @@ export function useInputField(params) {
 
             if (!isInvalid) {
                 pendingUpdate = true;
-                Promise.resolve(
-                    component.props.record.update({ [component.props.name]: val })
-                ).then(() => {
-                    pendingUpdate = false;
-                });
-                lastSetValue = ev.target.value;
-            }
+                lastSetValue = inputRef.el.value;
 
-            component.props.record.model.bus.trigger("FIELD_IS_DIRTY", isDirty);
+                await component.props.record.update({ [component.props.name]: val });
+                pendingUpdate = false;
+                component.props.record.model.bus.trigger("FIELD_IS_DIRTY", isDirty);
+            }
         }
     }
     function onKeydown(ev) {

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

@@ -1110,4 +1110,58 @@ QUnit.module("Fields", (hooks) => {
             assert.containsNone(target, "[name='display_name'] input");
         }
     );
+
+    QUnit.test(
+        "edit a char field should display the status indicator buttons without flickering",
+        async function (assert) {
+            serverData.models.partner.records[0].p = [2];
+            serverData.models.partner.onchanges = {
+                foo() {},
+            };
+
+            const def = makeDeferred();
+            await makeView({
+                type: "form",
+                resModel: "partner",
+                serverData,
+                resId: 1,
+                arch: `
+                    <form>
+                        <field name="p">
+                            <tree editable="bottom">
+                                <field name="foo"/>
+                            </tree>
+                        </field>
+                    </form>`,
+                async mockRPC(route, { method }) {
+                    if (method === "onchange") {
+                        assert.step("onchange");
+                        await def;
+                    }
+                },
+            });
+            assert.containsOnce(
+                target,
+                ".o_form_status_indicator_buttons.invisible",
+                "form view is not dirty"
+            );
+
+            await click(target, ".o_data_cell");
+            await editInput(target, "[name='foo'] input", "a");
+            assert.verifySteps(["onchange"]);
+            assert.containsOnce(
+                target,
+                ".o_form_status_indicator_buttons:not(.invisible)",
+                "form view is dirty"
+            );
+
+            def.resolve();
+            await nextTick();
+            assert.containsOnce(
+                target,
+                ".o_form_status_indicator_buttons:not(.invisible)",
+                "form view is dirty"
+            );
+        }
+    );
 });