MDL-49423 admin: Support optgroup in admin_setting_configmultiselect

admin/templates/setting_configmultiselect_optgroup.mustache

+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    @template core_admin/setting_configmultiselect_optgroup
+
+    Admin multiselect setting template with optgroup support.
+
+    Context variables required for this template:
+    * name - form element name
+    * id - element id
+    * size - element size
+    * options - list of options not grouped
+    * optgroups - list of options grouped containing the group label and for each option: name, value, selected
+
+    Example context (json):
+    {
+        "name": "test",
+        "id": "test0",
+        "size": "3",
+        "options": [
+            { "name": "Option 1", "value": "V", "selected": false },
+            { "name": "Option 2", "value": "V", "selected": true }
+        ],
+        "optgroups": [
+            {
+                "label": "Group 1",
+                "options": [
+                    { "name": "Option 3", "value": "V", "selected": false },
+                    { "name": "Option 4", "value": "V", "selected": true }
+                ]
+            },
+            {
+                "label": "Group 2",
+                "options": [
+                    { "name": "Option 5", "value": "V", "selected": false },
+                    { "name": "Option 6", "value": "V", "selected": true }
+                ]
+            }
+        ]
+    }
+}}
+<div class="form-select">
+    <input type="hidden" name="{{name}}[xxxxx]" value="1">
+    <select id="{{id}}" name="{{name}}[]" size="{{size}}" multiple>
+        {{#options}}
+            <option value="{{value}}" {{#selected}}selected{{/selected}}>{{name}}</option>
+        {{/options}}
+        {{#optgroups}}
+            <optgroup label="{{label}}">
+                {{#options}}
+                    <option value="{{value}}" {{#selected}}selected{{/selected}}>{{name}}</option>
+                {{/options}}
+            </optgroup>
+        {{/optgroups}}
+    </select>
+</div>
+

admin/upgrade.txt

@@ -2,8 +2,9 @@ This files describes API changes in /admin/*.
 
 === 3.3 ===
 
-* The admin setting admin_setting_configselect now support the optgroup tag. Grouping of options can be created with this new tag.
-  For using this new option, the option parameters needs the Group names as indexes:
+* The admin settings admin_setting_configselect and admin_setting_configmultiselect now support the optgroup tag.
+  Grouping of options can be created with this new tag.
+  For using it, the option parameters needs the Group names as indexes:
   [
     "Spain" =>  ["madrid" => "Madrid", "barcelona" => "Barcelona"],
     "France" => ["paris" => "Paris", "marseille" => "Marseille"],

lib/adminlib.php

@@ -3255,6 +3255,29 @@ class admin_setting_configmultiselect extends admin_setting_configselect {
 
         $defaults = [];
         $options = [];
+        $template = 'core_admin/setting_configmultiselect';
+
+        if (!empty($this->optgroups)) {
+            $optgroups = [];
+            foreach ($this->optgroups as $label => $choices) {
+                $optgroup = array('label' => $label, 'options' => []);
+                foreach ($choices as $value => $name) {
+                    if (in_array($value, $default)) {
+                        $defaults[] = $name;
+                    }
+                    $optgroup['options'][] = [
+                        'value' => $value,
+                        'name' => $name,
+                        'selected' => in_array($value, $data)
+                    ];
+                    unset($this->choices[$value]);
+                }
+                $optgroups[] = $optgroup;
+            }
+            $context->optgroups = $optgroups;
+            $template = 'core_admin/setting_configmultiselect_optgroup';
+        }
+
         foreach ($this->choices as $value => $name) {
             if (in_array($value, $default)) {
                 $defaults[] = $name;
@@ -3275,7 +3298,7 @@ class admin_setting_configmultiselect extends admin_setting_configselect {
             $defaultinfo = get_string('none');
         }
 
-        $element = $OUTPUT->render_from_template('core_admin/setting_configmultiselect', $context);
+        $element = $OUTPUT->render_from_template($template, $context);
 
         return format_admin_setting($this, $this->visiblename, $element, $this->description, true, '', $defaultinfo, $query);
     }

theme/boost/templates/core_admin/setting_configmultiselect_optgroup.mustache

+{{!
+    This file is part of Moodle - http://moodle.org/
+
+    Moodle is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Moodle is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+}}
+{{!
+    Setting configmultiselect with optgroup support.
+}}
+<div class="form-select">
+    <input type="hidden" name="{{name}}[xxxxx]" value="1">
+    <select id="{{id}}" name="{{name}}[]" size="{{size}}" class="form-control" multiple>
+    {{#options}}
+        <option value="{{value}}" {{#selected}}selected{{/selected}}>{{name}}</option>
+    {{/options}}
+    {{#optgroups}}
+            <optgroup label="{{label}}">
+                {{#options}}
+                    <option value="{{value}}" {{#selected}}selected{{/selected}}>{{name}}</option>
+                {{/options}}
+            </optgroup>
+        {{/optgroups}}
+    </select>
+</div>
+