MDL-75937 admin: Fixed config data display inconsistency

lib/adminlib.php

@@ -1820,7 +1820,7 @@ abstract class admin_setting {
         global $CFG;
 
         if (empty($this->plugin)) {
-            if (array_key_exists($this->name, $CFG->config_php_settings)) {
+            if ($this->is_forceable() && array_key_exists($this->name, $CFG->config_php_settings)) {
                 return true;
             }
         } else {
@@ -2164,6 +2164,18 @@ abstract class admin_setting {
     public function has_custom_form_control(): bool {
         return $this->customcontrol;
     }
+
+    /**
+     * Whether the setting can be overridden in config.php.
+     *
+     * Returning true will allow the setting to be defined and overridden in config.php.
+     * Returning false will prevent the config setting from being overridden even when it gets defined in config.php.
+     *
+     * @return bool
+     */
+    public function is_forceable(): bool {
+        return true;
+    }
 }
 
 /**
@@ -4600,6 +4612,15 @@ class admin_setting_sitesetselect extends admin_setting_configselect {
         return '';
 
     }
+
+    /**
+     * admin_setting_sitesetselect is not meant to be overridden in config.php.
+     *
+     * @return bool
+     */
+    public function is_forceable(): bool {
+        return false;
+    }
 }
 
 
@@ -4810,6 +4831,15 @@ class admin_setting_sitesetcheckbox extends admin_setting_configcheckbox {
 
         return '';
     }
+
+    /**
+     * admin_setting_sitesetcheckbox is not meant to be overridden in config.php.
+     *
+     * @return bool
+     */
+    public function is_forceable(): bool {
+        return false;
+    }
 }
 
 /**
@@ -4892,6 +4922,15 @@ class admin_setting_sitesettext extends admin_setting_configtext {
 
         return '';
     }
+
+    /**
+     * admin_setting_sitesettext is not meant to be overridden in config.php.
+     *
+     * @return bool
+     */
+    public function is_forceable(): bool {
+        return false;
+    }
 }
 
 
@@ -4967,6 +5006,15 @@ class admin_setting_special_frontpagedesc extends admin_setting_confightmleditor
 
         return '';
     }
+
+    /**
+     * admin_setting_special_frontpagedesc is not meant to be overridden in config.php.
+     *
+     * @return bool
+     */
+    public function is_forceable(): bool {
+        return false;
+    }
 }
 
 
@@ -9044,7 +9092,7 @@ function format_admin_setting($setting, $title='', $form='', $description='', $l
     $context->warning = $warning;
     $context->override = '';
     if (empty($setting->plugin)) {
-        if (array_key_exists($setting->name, $CFG->config_php_settings)) {
+        if ($setting->is_forceable() && array_key_exists($setting->name, $CFG->config_php_settings)) {
             $context->override = get_string('configoverride', 'admin');
         }
     } else {