Over the last week or so, I've occasionally struggled to fix a problem with the MoinMoin installation we use at work. The problem is that attaching files to a page doesn't work, even after enabling the appropriate configuration settings.
I spent hours looking at the AttachFile implementation, inserting debug prints which mysteriously weren't always executed on accessing a page, and getting increasingly frustrated. Today someone sent me a GIF file to manually drop into the Wiki repository, and I found that viewing the GIF didn't work either. This turned out to be a bug in the standalone web server MoinMoin provides. That turned my attention in the direction of the web server, and it soon became apparent that the attachment problem was also due to this; the server wasn't providing the Content-type header, so Python's cgi module didn't realize that it was multipart/form-data and never saw the uploaded file or any of the other fields.
It's a pity that MoinMoin had to reinvent so much web-related plumbing. Maybe after the Quixote 1.0 release comes out, I'll look at turning MoinMoin into a Quixote app. That would provide well-tested CGI, FastCGI, SCGI, and standalone support.