(or None) now. In 2.3a1 they could also return an int or long, but that
was an unhelpfully redundant leftover from an earlier version wherein
they couldn't return a timedelta. TOOWTDI.
On Windows, it was very common to get microsecond values (out of
.today() and .now()) of the form 480999, i.e. with three trailing
nines. The platform precision is .001 seconds, and fp rounding
errors account for the rest. Under the covers, that 480999 started
life as the fractional part of a timestamp, like .4809999978.
Rounding that times 1e6 cures the irritation.
Confession: the platform precision isn't really .001 seconds. It's
usually worse. What actually happens is that MS rounds a cruder value
to a multiple of .001, and that suffers its own rounding errors.
A tiny bit of refactoring added a new internal utility to round
doubles.
the test set as it only tested with a zip archive in the current directory,
but it doesn't work at all for packages when the zip archive was specified
as an absolute path. It's a real embarrassing bug: a strchr call should
have been strrchr; fever apparently implies dyslexia.
Second stupid bug: the zipimport test failed with a name error
__importer__ (which I had renamed to __loader__ everywhere but here).
I would've sworn I ran the test after that change but that can't be true.
What I don't understand that noone reported a failing test_zipimport.py
before the release of 2.3a1.
suggestion from Guido, along with a formal correctness proof of the
trickiest bit. The intricacy of the proof reveals how delicate this
is, but also how robust the conclusion: correctness doesn't rely on
dst() returning +- one hour (not all real time zones do!), it only
relies on:
1. That dst() returns a (any) non-zero value if and only if daylight
time is in effect.
and
2. That the tzinfo subclass implements a consistent notion of time zone.
The meaning of "consistent" was a hidden assumption, which is now an
explicit requirement in the docs. Alas, it's an unverifiable (by the
datetime implementation) requirement, but so it goes.
find a more elegant algorithm (OTOH, the hairy new implementation allows
user-written tzinfo classes to be elegant, so it's a big win even if
astimezone() remains hairy).
Darn! I've only got 10 minutes left to get falling-down drunk! I suppose
I'll have to smoke crack instead now.
The attached patch enables Cygwin Python to
build cleanly against the latest Cygwin Tcl/Tk
which is based on Tcl/Tk 8.3. It also prevents
building against the real X headers, if installed.
A variety of changes from Michael Hudson to get the compiler working
with 2.3. The primary change is the handling of SET_LINENO:
# The set_lineno() function and the explicit emit() calls for
# SET_LINENO below are only used to generate the line number table.
# As of Python 2.3, the interpreter does not have a SET_LINENO
# instruction. pyassem treats SET_LINENO opcodes as a special case.
A few other small changes:
- Remove unused code from pycodegen and pyassem.
- Fix error handling in parsermodule. When PyParser_SimplerParseString()
fails, it sets an exception with detailed info. The parsermodule
was clobbering that exception and replacing it was a generic
"could not parse string" exception. Keep the original exception.
an idea from Guido. This restores that the datetime implementation
never passes a datetime d to a tzinfo method unless d.tzinfo is the
tzinfo instance whose method is being called. That in turn allows
enormous simplifications in user-written tzinfo classes (see the Python
sandbox US.py and EU.py for fully fleshed-out examples).
d.astimezone(tz) also raises ValueError now if d lands in the one hour
of the year that can't be expressed in tz (this can happen iff tz models
both standard and daylight time). That it used to return a nonsense
result always ate at me, and it turned out that it seemed impossible to
force a consistent nonsense result under the new implementation (which
doesn't know anything about how tzinfo classes implement their methods --
it can only infer properties indirectly). Guido doesn't like this --
expect it to change.
New tests of conversion between adjacent DST-aware timezones don't pass
yet, and are commented out.
Running the datetime tests in a loop under a debug build leaks 9
references per test run, but I don't believe the datetime code is the
cause (it didn't leak the last time I changed the C code, and the leak
is the same if I disable all the tests that invoke the only function
that changed here). I'll pursue that next.
