"%01.3f" % nil
Should throw a TypeError
This patch will work, but it's a total hack. (The problem goes to the overall design of PrintfFormat – there isn't a clean fix.) Solves similar non-compliance issues with nil and other format specifiers.
I will take this for a spin...Looks reasonable and I would guess safe. This code is going away soon so a hack is fine. Thanks Bill.
Applied in commit 3121 with one unit test (we should add several failing format tests when rewrite lands). Thanks Bill