Thread:Extension talk:Gadgets/mw.loader::execute Exception thrown by ext.gadget.mySandbox: Bad constructor arguments/reply (3)

i believe it's the other way around: title.getUrl actually is supposed to return the relative path (i.e., "/wiki/Special:MyPage/sandbox"). however, the mw.Uri is supposed to live peacefully with this value. so it seems that the problem lies with the mw.Uri object.

my guess is that some value this library expects to have a value which should be set in LocalSettings.php, either does not have a value, or has bad value.