Fix column suggestions for empty custom vars of type array

library/Icingadb/Web/Control/SearchBar/ObjectSuggestions.php

@@ -212,16 +212,23 @@ protected function fetchColumnSuggestions($searchTerm)
 
  // Custom variables only after the columns are exhausted and there's actually a chance the user sees them
  $titleAdded = false;
+ $parsedArrayVars = [];
  foreach ($this->getDb()->select($this->queryCustomvarConfig($searchTerm)) as $customVar) {
  $search = $name = $customVar->flatname;
- if (preg_match('/\w+\[(\d+)]$/', $search, $matches)) {
- // array vars need to be specifically handled
- if ($matches[1] !== '0') {
+ if (preg_match('/\w+\[(\d*)]$/', $search, $matches)) {
+ if ($matches[1] !== "" && $matches[1] !== '0') {
  continue;
  }
 
- $name = substr($search, 0, -3);
+ $name = substr($search, 0, $matches[1] === "" ? -2 : -3);
+ if (isset($parsedArrayVars[$name])) {
+ continue;
+ }
+
+ $parsedArrayVars[$name] = true;
  $search = $name . '[*]';
+ } elseif (substr($name, -1) === '.') {
+ $name = substr($name, 0, -1) . ' (empty)';
  }
 
  foreach ($this->customVarSources as $relation => $label) {