Patches item #1623563, was opened at 2006-12-28 03:48 Message generated for change (Comment added) made by nnorwitz You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=305470&aid=1623563&group_id=5470
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Core (C code) Group: Python 2.6 Status: Open Resolution: Accepted Priority: 5 Private: No Submitted By: TH (therve) Assigned to: Žiga Seilnacht (zseil) Summary: Allow __class __ assignment for classes with __slots__ Initial Comment: I made a modification in typeobject.c to allow __class__ modification for classes with slots. It's basically a change in same_slots_added to count the offset of the slots and check if the names of the slots are the same (in the naive way). I don't check if slots are in a different order, that may be an improve. The patch is against trunk, with some tests. It's my first submission on Python, so every feedback will be welcome :). ---------------------------------------------------------------------- >Comment By: Neal Norwitz (nnorwitz) Date: 2007-03-15 15:56 Message: Logged In: YES user_id=33168 Originator: NO Go ahead and check in. Thanks! ---------------------------------------------------------------------- Comment By: Žiga Seilnacht (zseil) Date: 2007-03-15 11:51 Message: Logged In: YES user_id=1326842 Originator: NO Hi Neal, Yes, an exception in slots comparison would get overwritten, but I think that this is highly unlikely to happen. The user would have to put a malicious string into __slots__, and that string would have to go through list sorting in type_new() without raising an error. The original object is never stored in ht_slots; type_new() always constructs a new tuple from the sorted slot names. I'll leave the patch open until tomorow in case you have any other concerns, and then check it in. ---------------------------------------------------------------------- Comment By: Neal Norwitz (nnorwitz) Date: 2007-03-14 22:42 Message: Logged In: YES user_id=33168 Originator: NO Sorry about the typo, I did mean remove, not review. The latest patch looks good. I have some questions though. What would happen if an exception is raised when comparing slots? I think it will be ok, the exception would get overwritten with the one about incompatible types/__slots__. I just want to be safe and it might be good to at least test this manually. Is the original object saved in ht_slots or is it always a tuple? If the original object is used, what if you have two classes with the same slots, but one uses a list and the other uses a tuple for __slots__? ---------------------------------------------------------------------- Comment By: Žiga Seilnacht (zseil) Date: 2007-03-14 07:24 Message: Logged In: YES user_id=1326842 Originator: NO The ht_slots tuple can't contain unicode names; they are converted to strings in type_new(). type_new() also raises an error for any non string object found in __slots__. At the end of type_new(), ht_slots tuple can only contain valid identifiers minus __weakref__ and __dict__. I changed the patch to use PyObject_Compare() anyway, because it reduces the amount of code. I also removed whitespace changes in the docs, changed the tests as suggested and added a test with unicode slots. File Added: same_slots_added_5.diff ---------------------------------------------------------------------- Comment By: TH (therve) Date: 2007-03-14 04:22 Message: Logged In: YES user_id=1038797 Originator: YES > Ziga, there are a lot of changes to the doc that appear to be whitespace > only. Could you review them from the patch before checkin? I guess you mean "remove them" ? > I see _PyString_Eq is used. It's possible that __slots__ contain unicode, > possibly other types (I didn't check). It seems __slots__ can be unicode, but only with ascii content. This behavior is a bit weird... ---------------------------------------------------------------------- Comment By: Neal Norwitz (nnorwitz) Date: 2007-03-13 21:01 Message: Logged In: YES user_id=33168 Originator: NO Ziga, there are a lot of changes to the doc that appear to be whitespace only. Could you review them from the patch before checkin? If you want to make whitespace/formatting changes, that's fine, but it's a lot easier to review if there are 2 separate checkins. In the test, it looks like it would be much easier to unpack the classes in the loop, since you know there are two. That would eliminate 2 of the inner loops which don't seem necessary. for cls1, cls2 in ((G, H), (P, Q)): Also, when doing data driven tests, it's important to add an error message about which iteration failed. Right now, you wouldn't know if G/H failed or P/Q failed since the line number will be the same. If you add a message to the assertions which contains data, then it's clear from the message which one failed. typeobject.c I see _PyString_Eq is used. It's possible that __slots__ contain unicode, possibly other types (I didn't check). What happens if non-strings are in __slots__ with this patch applied? The calculation for size could be done outside the loop with a multiply. I don't know which would be faster. I don't really care which is used either. Just something I noticed. ---------------------------------------------------------------------- Comment By: TH (therve) Date: 2007-03-13 10:12 Message: Logged In: YES user_id=1038797 Originator: YES That's great, thanks a lot for you help. ---------------------------------------------------------------------- Comment By: Žiga Seilnacht (zseil) Date: 2007-03-13 09:16 Message: Logged In: YES user_id=1326842 Originator: NO The only problem that I see with this patch is that slot names have to be listed in both classes in the same order for __class__ assignment to work. This could have strange consequences when a dict is used for __slots__. I'm attaching a patch that fixes this, with modified test and documentation. The change had to be done in type_new() function, by sorting slotnames before the creation of member descriptors. Most of the documentation changes are whitespace cleanup. File Added: same_slots_added_4.diff ---------------------------------------------------------------------- Comment By: TH (therve) Date: 2007-03-08 05:08 Message: Logged In: YES user_id=1038797 Originator: YES File Added: same_slots_added_3.diff ---------------------------------------------------------------------- Comment By: Žiga Seilnacht (zseil) Date: 2007-03-07 09:07 Message: Logged In: YES user_id=1326842 Originator: NO The PyObject * cast is reduntant, but otherwise the patch looks good to me. I added a few more tests, but I can't attach a file so I posted them here: http://freeweb.siol.net/chollus/ ---------------------------------------------------------------------- Comment By: TH (therve) Date: 2007-03-07 05:05 Message: Logged In: YES user_id=1038797 Originator: YES Thanks, I wasn't able to find this function. I updated the patch for using this. File Added: same_slots_added_2.diff ---------------------------------------------------------------------- Comment By: TH (therve) Date: 2007-03-07 05:04 Message: Logged In: YES user_id=1038797 Originator: YES File Added: same_slots_added_2.diff ---------------------------------------------------------------------- Comment By: Žiga Seilnacht (zseil) Date: 2007-03-06 10:07 Message: Logged In: YES user_id=1326842 Originator: NO You should use _PyString_Eq() for string comparison instead of relying on the internal details of PyStringObject. ---------------------------------------------------------------------- Comment By: Jim Jewett (jimjjewett) Date: 2007-02-08 10:41 Message: Logged In: YES user_id=764593 Originator: NO Review five other patches. Post the review summaries (and tracker numbers) to the python-dev mailing list. In that same message, ask someone with commit privileges to do the 5:1 deal, pointing at this tracker number. ---------------------------------------------------------------------- Comment By: TH (therve) Date: 2007-02-06 05:43 Message: Logged In: YES user_id=1038797 Originator: YES Is there anything I can do to have a resolution on this ? Thanks. ---------------------------------------------------------------------- Comment By: Jim Jewett (jimjjewett) Date: 2006-12-30 16:26 Message: Logged In: YES user_id=764593 Originator: NO Just going through the list doesn't seem so naive to me. If the slots are in a different order, then you would need to move the data around -- which borders on "maybe they ought to have written the translator themselves" ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=305470&aid=1623563&group_id=5470 _______________________________________________ Patches mailing list Patches@python.org http://mail.python.org/mailman/listinfo/patches
