[Bf-committers] Reference counting, deleting data and fake users

[Nicholas Bishop]

It's not a problem specific to actions; brush blocks have the same
issue (because the paint modes have only a single brush pointer), so
we set the fakeuser flag when new brushes are added.

-Nicholas

On Wed, Mar 14, 2012 at 2:40 PM, Tom Edwards <contact at steamreview.org> wrote:
> This is a problem specific to Actions. An object can have any number of
> relevant Actions, but it can only _use_ one at a time. Shameless plug:
> there's a patch at
> <http://projects.blender.org/tracker/index.php?func=detail&aid=28453>
> that fixes this problem.
>
> It's possible to get into this situation with other data types, but that
> requires the user to do advanced things like manually change an object's
> data or to explicitly delete the datablock.
>
> On 14/03/2012 6:20, Antony Riakiotakis wrote:
>> Interesting ranting post on blenderartists about data lost due to user
>> not setting fake user on datablock.
>>
>> http://blenderartists.org/forum/showthread.php?248813-MAJOR-BUG-in-2.62-loosing-Actions/page1
>>
>> The point is, in my opinion: Should the user care about the number of
>> datablock references? This looks like something that would concern the
>> reference counting system of a memory manager/garbage collector rather
>> than users.
>>
>> This would not have been a problem if we had an explicit way to delete
>> data and data always stayed in blender even after closing the program.
>> A user will usually want his data to stay if he creates it and go if
>> he deletes it. Currently there are two problems with the approach we
>> have: 1) You have to close the program to delete all unreferenced data
>> and 2) You can't create a library of datablocks without explicitly
>> setting a fake user, which is not the best of options.
>>
>> I realize this might have been a popular theme of debate but I am not
>> up to the facts. Is this a design choice or simply not  implemented
>> yet? Is this part of the asset browser project?
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