util.error: Fix error on conversion of invalid error stanza, fix #1805 Error stanzas should have an <error> element, but if you pass a stanza without one to util.error.from_stanza() it triggers an attempt to index a nil value, which this patch avoids. In the conditional, it should be safe to assume error_tag is non-nil since condition can't have those values then.

local set = require "util.set";

return {
	available = set.new{
		-- mod_bookmarks bundled
		"mod_bookmarks";
	};
};