[FIX] web: datepicker: crash on invalid date

There is an open issue on the tempusdominus lib:
https://github.com/tempusdominus/bootstrap-4/issues/223

It occurs when there is a valid value in a date(time) field, and
the user unsets it by setting an invalid one.

This rev. fixes the issue in Odoo by preventing to reach the buggy
piece of code in the lib. In a few words, when the user sets an
invalid date, we reset the previous valid date (which is what the
lib tries to do anyway).

Task 2057009

closes odoo/odoo#36211

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


Co-authored-by: Aaron Bohy <aab@odoo.com>

addons/web/static/src/js/widgets/date_picker.js

@@ -84,8 +84,8 @@ var DateWidget = Widget.extend({
      * set datetime value
      */
     changeDatetime: function () {
+        var oldValue = this.getValue();
         if (this.isValid()) {
-            var oldValue = this.getValue();
             this._setValueFromUi();
             var newValue = this.getValue();
             var hasChanged = !oldValue !== !newValue;
@@ -102,6 +102,9 @@ var DateWidget = Widget.extend({
                 }
                 this.trigger("datetime_changed");
             }
+        } else {
+            var formattedValue = oldValue ? this._formatClient(oldValue) : null;
+            this.$input.val(formattedValue);
         }
     },
     /**

addons/web/static/tests/fields/basic_fields_tests.js

@@ -2696,8 +2696,32 @@ QUnit.module('basic_fields', {
         form.destroy();
     });
 
-    QUnit.test('date field should remove the date  if the date is not valid', function (assert) {
-        assert.expect(1);
+    QUnit.test('date field: set an invalid date when the field is already set', function (assert) {
+        assert.expect(2);
+
+        var form = createView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form string="Partners"><field name="date"/></form>',
+            res_id: 1,
+            viewOptions: {
+                mode: 'edit',
+            },
+        });
+
+        var $input = form.$('.o_field_widget[name=date] input');
+
+        assert.strictEqual($input.val(), "02/03/2017");
+
+        $input.val('mmmh').trigger('change');
+        assert.strictEqual($input.val(), "02/03/2017", "should have reset the original value");
+
+        form.destroy();
+    });
+
+    QUnit.test('date field: set an invalid date when the field is not set yet', function (assert) {
+        assert.expect(2);
 
         var form = createView({
             View: FormView,
@@ -2705,13 +2729,18 @@ QUnit.module('basic_fields', {
             data: this.data,
             arch: '<form string="Partners"><field name="date"/></form>',
             res_id: 4,
+            viewOptions: {
+                mode: 'edit',
+            },
         });
-        // switch to edit mode
-        form.$buttons.find('.o_form_button_edit').click();
-        // set an invalid date
+
         var $input = form.$('.o_field_widget[name=date] input');
+
+        assert.strictEqual($input.text(), "");
+
         $input.val('mmmh').trigger('change');
         assert.strictEqual($input.text(), "", "The date field should be empty");
+
         form.destroy();
     });