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Re: [StGIT PATCH 3/5] Create a git.Branch class as ancestor of stack.Stack

From
Karl Hasselström <kha@treskal.com>
Date
Jun 7, 2008, 09:06 UTC
Message-ID
<20080607090636.GB32647@diana.vm.bytemark.co.uk>
In-Reply-To
<b0943d9e0806060144x48176566m277ba2969087b91e@mail.gmail.com>
On 2008-06-06 09:44:37 +0100, Catalin Marinas wrote:
Show 10 quoted lines
> 2008/6/5 Karl Hasselström <kha@treskal.com>:
>
> > We'll have to be watchful against attempts to create objects other
> > than via the officially designated factories, though. Python
> > doesn't really have any mechanisms that help us here.
>
> Doesn't need to be enforced. The Stack and Branch objects can be
> initialised by themselves provided that the repository is passed as
> argument at construction. The factory is more for convenience,
> passing the repository to the newly created object.

Those classes cache stuff. So if you have, say, two PatchOrder objects representing the same underlying files, an update in one will not be reflected in the other. An important role of the factory is to make sure that if an object is asked for twice, the _same_ object is returned to both callers.

The Commit, Tree, and Blob objects produced by Repository are another example where we rely on there being no more than one Python object representing the same underlying data.

> If you really want enforcing this, it can probably be done by
> hacking __new__ and __init__.

No, I reckon you're right -- it's overkill. StGit is small enough that we can probably enforce the relevant restrictions by hand.

-- 
Karl Hasselström, kha@treskal.com
      www.treskal.com/kalle
Previous: Catalin MarinasNext: Catalin Marinas
Message 16 of 28 in “Various updates to the new infrastructure”
  1. 0/5 Various updates to the new infrastructureCatalin Marinas, Jun 4, 2008
  2. 1/5 Allow stack.patchorder.all to return hidden patchesCatalin Marinas, Jun 4, 2008
  3. Karl HasselströmJun 5, 2008
  4. Catalin MarinasJun 5, 2008
  5. 2/5 Rename Repository.head to Repository.head_refCatalin Marinas, Jun 4, 2008
  6. Karl HasselströmJun 5, 2008
  7. Catalin MarinasJun 5, 2008
  8. Karl HasselströmJun 5, 2008
  9. Catalin MarinasJun 5, 2008
  10. Karl HasselströmJun 5, 2008
  11. 3/5 Create a git.Branch class as ancestor of stack.StackCatalin Marinas, Jun 4, 2008
  12. Karl HasselströmJun 5, 2008
  13. Catalin MarinasJun 5, 2008
  14. Karl HasselströmJun 5, 2008
  15. Catalin MarinasJun 6, 2008
  16. Karl HasselströmJun 7, 2008
  17. Catalin MarinasJun 8, 2008
  18. David AguilarJun 9, 2008
  19. Sverre RabbelierJun 9, 2008
  20. Karl HasselströmJun 9, 2008
  21. 4/5 Add stack creation and initialisation support to lib.StackCatalin Marinas, Jun 4, 2008
  22. Karl HasselströmJun 5, 2008
  23. Catalin MarinasJun 5, 2008
  24. Karl HasselströmJun 7, 2008
  25. 5/5 Add stack creation and deletion support to the new infrastructureCatalin Marinas, Jun 4, 2008
  26. Karl HasselströmJun 5, 2008
  27. Catalin MarinasJun 5, 2008
  28. Karl HasselströmJun 5, 2008

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