Murphy willing (idiom). If nothing goes wrong. Also: Murphy-willing.
Django-Dojo alliance was finally announced to the world by our very own Jacob Kaplan-Moss:
Starting with version 0.92 (which should be out in a few weeks, Murphy willing), Django is going to bundle Dojo with the toolkit.
—Eugene Lazutkin, "Django Dojo," Eugene's Blog, January 28, 2006
If you have a moment and the URL for an interesting video clip, try adding to the schedule! Murphy willing, a new item will appear in the feed each night. When the item goes live on the feed, also Murphy willing, the item will appear, with details, on this weblog and be open for comment.
—Andrew Grumet, "Personal TV Networks," Andrew Grumet's Weblog, July 15, 2004
Side-note: We've been archiving the My.UserLand.Com channels, so if historians want to trace the development of syndication on the web, we'll be able to give them a clue. Murphy-willing!
—Dave Winer, Scripting News Archive, June 23, 1999
This phrase is a secular play on the very old (15th century) phrase God willing, and it comes from Murphy's Law: in a given situation, if anything can go wrong it will. Murphy's Law was named after U.S. Air Force Captain Edward A. Murphy, who performed deceleration studies in the 1940s and noted that if things could be done wrongly, they would be.
I got this from The Word Spy: