- $this->page = (int)$this->arg('page', 1);
- $this->count = (int)$this->arg('count', 20);
- $this->max_id = (int)$this->arg('max_id', 0);
- $this->since_id = (int)$this->arg('since_id', 0);
- $this->since = $this->arg('since');
-
- $this->format = $this->arg('format');
- $this->group = $this->getTargetGroup($this->arg('id'));
+ $this->group = $this->getTargetGroup($this->arg('id'));
+ if (empty($this->group)) {
+ // TRANS: Client error displayed trying to show group membership on a non-existing group.
+ $this->clientError(_('Group not found.'), 404, $this->format);
+ return false;
+ }