The messages on the error pages must be improved. See also bug 26048 comment 19.
Moving the comment here: (In reply to Jonathan Druart from comment #19) > Thanks David, I was missing HTTPExceptions to make it works that way! > > We should update the list of reasons of the 500 > """ > You made use of an external link to an item that is no longer available > You followed an outdated link e.g. from a search engine or a bookmark > You tried to access a page that needs authentication > An internal link in the client is broken and the page does not exist > """ > At least the 3rd one is wrong. > > The most probable reason is that there is a bug :D > > Yesterday I was thinking we could have a syspref to display/hide the error > (not the stacktrace). Or enable it by default for superlibrarian. What do > you think (on its own bug report of course)?