[FIX] web: Make datetimepicker configurable in datetime fields

The datetimepicker option was introduced to be able to customize the
datetime picker widget in date/datetime fields. However, due to the way
the _makeDatePicker function was coded, it did not work in datetime
fields.

Thank to Yajo for the initial fix

closes odoo/odoo#27541

addons/web/static/src/js/fields/basic_fields.js

@@ -404,6 +404,10 @@ var FieldDate = InputField.extend({
         this._super.apply(this, arguments);
         // use the session timezone when formatting dates
         this.formatOptions.timezone = true;
+        this.datepickerOptions = _.defaults(
+            this.nodeOptions.datepicker || {},
+            {defaultDate: this.value}
+        );
     },
     /**
      * In edit mode, instantiates a DateWidget datepicker and listen to changes.
@@ -468,13 +472,7 @@ var FieldDate = InputField.extend({
      * @private
      */
     _makeDatePicker: function () {
-        return new datepicker.DateWidget(
-            this,
-            _.defaults(
-                this.nodeOptions.datepicker || {},
-                {defaultDate: this.value}
-            )
-        );
+        return new datepicker.DateWidget(this, this.datepickerOptions);
     },
 
     /**
@@ -492,6 +490,17 @@ var FieldDate = InputField.extend({
 var FieldDateTime = FieldDate.extend({
     supportedFieldTypes: ['datetime'],
 
+    /**
+     * @override
+     */
+    init: function () {
+        this._super.apply(this, arguments);
+        if (this.value) {
+            var offset = this.getSession().getTZOffset(this.value);
+            var displayedValue = this.value.clone().add(offset, 'minutes');
+            this.datepickerOptions.defaultDate = displayedValue;
+        }
+    },
     //--------------------------------------------------------------------------
     // Private
     //--------------------------------------------------------------------------
@@ -522,10 +531,8 @@ var FieldDateTime = FieldDate.extend({
      * @private
      */
     _makeDatePicker: function () {
-        var value = this.value && this.value.clone().add(this.getSession().getTZOffset(this.value), 'minutes');
-        return new datepicker.DateTimeWidget(this, {defaultDate: value});
+        return new datepicker.DateTimeWidget(this, this.datepickerOptions);
     },
-
     /**
      * Set the datepicker to the right value rather than the default one.
      *

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

@@ -2556,6 +2556,33 @@ QUnit.module('basic_fields', {
         form.destroy();
     });
 
+    QUnit.test('datepicker option: daysOfWeekDisabled', function (assert) {
+        assert.expect(2);
+
+        this.data.partner.fields.datetime.default = "2017-08-02 12:00:05";
+        this.data.partner.fields.datetime.required = true;
+
+        var form = createView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch:'<form string="Partners">' +
+                    '<field name="datetime" ' +
+                            'options=\'{"datepicker": {"daysOfWeekDisabled": [0, 6]}}\'/>' +
+                '</form>',
+            res_id: 1,
+        });
+
+        form.$buttons.find('.o_form_button_create').click();
+        form.$('.o_datepicker_input.o_input').click();
+        assert.ok($('.day:last-child(),.day:nth-child(2)').hasClass('disabled'),
+            'first and last days must be disabled');
+        assert.notOk($('.day:not(:last-child()):not(:nth-child(2))').hasClass('disabled'),
+            'other days must stay clickable');
+
+        form.destroy();
+    });
+
     QUnit.module('FieldMonetary');
 
     QUnit.test('monetary field in form view', function (assert) {

doc/reference/javascript_reference.rst

@@ -1348,7 +1348,7 @@ order.
 
     .. code-block:: xml
 
-        <field name="datefield" options='{"datepicker": {"daysOfWeekDisabled": [0, 6]}}'/>
+        <field name="datetimefield" options='{"datepicker": {"daysOfWeekDisabled": [0, 6]}}'/>
 
 - monetary (FieldMonetary)
     This is the default field type for fields of type 'monetary'. It is used to