By controversy I mean the matter of Django transition to GitHub that IIRC was a subject for discussions for a long time.
A, no problem. I'm a non-native English speaker myself. It's so known a use that it's even in the dictionary:
Post Mortem: 2. Informal An analysis or review of a finished event.
Funny aside: in my language we have a similar half-joking phrase.
When someone asks "How did it go?" after you've done anything that you're uncertain about it's outcome (a job interview, exams, your book getting published, etc), a common answer is "The autopsy will show us".
However, I still generally avoid using that joke with sensitive/more formal matter, preferring to err on the safe side. (Here, as well, misunderstanding might've occurred because the context was a bit less formal than I expected.)
I didn't pay much attention to dictionary references in this thread because I don't trust dictionary much when specific word's usage is in question, more relying on personal experience. Although maybe I should simply get a more extensive dictionary than what ships with OS X—the big problem with the above approach, of course, is that if I never saw a phrase used in some way, it may only mean I never had a chance to.
Judging from your profile info, we do not share a language, but we share a religion (our countries do, that is).
It's a well known, and extensively used manner of speaking.
There is no controversy --nor should we aspire to avoid "all controversy" by going into laughable measures like censoring stock standard phrases.