Last modified: 2013-03-28 15:29:50 UTC
I've noticed on the English Wikipedia that when previewing Lua modules using the "preview page with this template" option, if there is a script error, the JavaScript error message doesn't show up when you click the link. To demonstrate this, I have made the following: https://en.wikipedia.org/wiki/Module:User:Mr._Stradivarius/previewbug https://en.wikipedia.org/wiki/User:Mr._Stradivarius/Sandbox/Previewbug If you click on the link in [[User:Mr. Stradivarius/Sandbox/Previewbug]] you can see the error message, but if you edit [[Module:User:Mr. Stradivarius/previewbug]] and then use "preview page with this template" with "User:Mr. Stradivarius/Sandbox/Previewbug", the error message does not appear. However, this bug does not occur on the test2 wiki. I've made equivalent sandbox and module pages at: https://test2.wikipedia.org/wiki/Module:User:Mr._Stradivarius/sandbox https://test2.wikipedia.org/wiki/User:Mr._Stradivarius/sandbox The error message displays fine with these pages. Because of this I'm not sure where the bug is. But according to [1], en.wiki and test2 are running the same version of Scribunto, so it's not a delay between patching one and patching the other. Therefore I'm submitting a bug here in case it is a software-side problem. [1] https://en.wikipedia.org/w/index.php?title=Wikipedia:Village_pump_%28technical%29&oldid=547427635#Lua_error_messages_not_displaying_on_.22preview_page_with_this_template.22
Works for me when following the directions you give. I've replied at the linked VP thread; at the moment, I suspect some sort of error in your user JS is preventing Scribunto's script for the error popup from running correctly.
Per discussion on the VP thread, this was an issue with a gadget on enwiki throwing errors and preventing Scribunto's javascript from executing.