Message 89665 - Python tracker

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In-reply-to
Author	mark.dickinson
Recipients	ezio.melotti, mark.dickinson, mfxmfx, rhettinger
Date	2009年06月24日.13:56:48
SpamBayes Score	3.6981562e-06
Marked as misclassified	No
Message-id	<1245851810.62.0.689653868259.issue6334@psf.upfronthosting.co.za>

Content
The length calculation in range_iter in Objects/rangeobject.c is incorrect, when using a longrangeiterobject. The length is computed as: (stop - start)//step. It should be ceiling((stop-start)/step), or 1 + (stop - start - 1)//step, provided that start <= stop and step > 0. It's not clear to me right now whether there may also be problems with negative steps, and with cases where start < stop, etc. I think this is serious enough to be considered a release blocker for 3.1; I'm working on a patch, and will post it later today.

Content

The length calculation in range_iter in Objects/rangeobject.c is 
incorrect, when using a longrangeiterobject. The length is computed
as: (stop - start)//step. It should be ceiling((stop-start)/step), or
1 + (stop - start - 1)//step, provided that start <= stop and step > 0.
It's not clear to me right now whether there may also be problems with 
negative steps, and with cases where start < stop, etc.
I think this is serious enough to be considered a release blocker for 3.1; 
I'm working on a patch, and will post it later today.

History
Date	User	Action	Args
2009年06月24日 13:56:51	mark.dickinson	set	recipients: + mark.dickinson, rhettinger, ezio.melotti, mfxmfx
2009年06月24日 13:56:50	mark.dickinson	set	messageid: <1245851810.62.0.689653868259.issue6334@psf.upfronthosting.co.za>
2009年06月24日 13:56:48	mark.dickinson	link	issue6334 messages
2009年06月24日 13:56:48	mark.dickinson	create

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