[Python-Dev] User's complaints (original) (raw)

Brett Cannon brett at python.org
Wed Jul 12 03:05:21 CEST 2006

On 7/11/06, skip at pobox.com <skip at pobox.com> wrote:

Michael> Well here's one I stumbled across the other day. I don't know Michael> if it's legit, but it's still bad PR: Michael> http://www.gbch.net/gjb/blog/software/discuss/python-sucks.html Michael> For the impatient, he's not at all bothered about the lack of Michael> obscure language feature X.

That whole entry is a little overblown. I mean the guy has a single issue with a change and he gives up on the language after only the second one? Try using any language that is under active development and show me stuff that won't break. I think it shows how hard we work to not break things that this guy only got bit twice, and at least the second time was minor and had a legit reason for the change.

The way I used to format dates using time.strftime does indeed no longer

work.

Python 2.3: >>> import time >>> time.strftime("%Y-%m-%d", (2005, 6, 4) + (0,)*6) '2005-06-04' Python 2.4 or 2.5: >>> import time >>> time.strftime("%Y-%m-%d", (2005, 6, 4) + (0,)*6) Traceback (most recent call last): File "", line 1, in ? ValueError: day of year out of range >>> time.strftime("%Y-%m-%d", (2005, 6, 4) + (1,)*6) '2005-06-04'

That was done to fix buffer overflow issues when libc implementations didn't do bound checks on the arguments to strftime() and would index too far (e.g., setting the month as 20 indexes too far and setting to 0 can be an issue as well since the array indexing for the month name will be January, and thus will most likely do mon - 1 to get the index into the array).

I don't actually run into this problem as I've pretty much converted to use

datetime in new code. I also realize that's not documented as the way it should be done,

It is the last point in the first paragraph on time.strftime() discussing what changed in Python 2.4 as to what the change was. It's also in Misc/NEWS . Basically the guy didn't read the release notes or the docs to see why that changed and that it was legitimate and needed for stability.

but I'm fairly certain it was common usage before the

datetime module came along. Still, it is a bit annoying that the (undocumented, but I think de facto) commonly used idiom no longer works.

As I said, stability called for the need to make the change. It was discussed on python-dev when it came up.

(In fact, it always bothered me a bit that I had to even provide the unused

values.)

That would probably be fine to add in 2.6 . Should be a huge issue. You could also change the function to detect values of 0 when provided and then automatically use defaults in those cases that are within the proper range.

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