http://sourceforge.net/tracker/index.php?func=detail&aid=415514&group_id=5470&atid=105470
For short ints, Python defers to the platform C library to figure out what
%#x should do. The code asserted that the platform C returned a string
beginning with "0x". However, that's not true when-- and only when --the
*value* being formatted is 0. Changed the code to live with C's inconsistency
here. In the meantime, the problem does not arise if you format a long 0 (0L)
instead. However, that's because the code *we* wrote to do %#x conversions on
longs produces a leading "0x" regardless of value. That's probably wrong too:
we should drop leading "0x", for consistency with C, when (& only when) formatting
0L. So I changed the long formatting code to do that too.
and replaces them with a new API verify(). As a result the regression
suite will also perform its tests in optimization mode.
Written by Marc-Andre Lemburg. Copyright assigned to Guido van Rossum.
Note a curious extension to the std C rules: x, X and o formatting can never produce
a sign character in C, so the '+' and ' ' flags are meaningless for them. But
unbounded ints *can* produce a sign character under these conversions (no fixed-
width bitstring is wide enough to hold all negative values in 2's-comp form). So
these flags become meaningful in Python when formatting a Python long which is too
big to fit in a C long. This required shuffling around existing code, which hacked
x and X conversions to death when both the '#' and '0' flags were specified: the
hacks weren't strong enough to deal with the simultaneous possibility of the ' ' or
'+' flags too, since signs were always meaningless before for x and X conversions.
Isomorphic shuffling was required in unicodeobject.c.
Also added dozens of non-trivial new unbounded-int test cases to test_format.py.
Tim Peters