While using https://twitter.com/ (I think I was trying to search for a user in the box at the top), I hit the fatal assertion: Assertion failure: aFirst && aSecond (Don't pass null pointers!), at /home/dbaron/builds/ssd/mozilla-central/mozilla/caps/src/nsScriptSecurityManager.cpp:941 Might not be caps's fault, though, given the massive instability in builds today.
Hit it a second time, just loading https://twitter.com/
So, this is happening because the old-fashioned mechanism for accessing object principals (which we invoke in debug builds to check our results) is returning null for some reason. I'm mildly curious to know why, but I think this code can also just go away. I'll attach a patch.
Created attachment 806087 [details] [diff] [review] Remove old-style object principal calculation. v1
Comment on attachment 806087 [details] [diff] [review] Remove old-style object principal calculation. v1 r=me