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Re: (guix git) and guile-git finalizers.

From: Andy Wingo
Subject: Re: (guix git) and guile-git finalizers.
Date: Thu, 22 Jun 2017 13:40:06 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux)

Hi :)

Just some code review.

On Mon 19 Jun 2017 18:01, Mathieu Othacehe <address@hidden> writes:

> The idea here is to create a guardian per pointer-type to finalize. A
> pumper function that operates on this guardian is also created. This
> pumper function knows the git_libgit2_xxx function to call to free the
> pointers stored in guardians.

Neat.  A couple problems though.

  (1) All finalizable objects will be kept alive until they are removed
  from the guardian.  With guardians, you usually want to incrementally
  visit it during program execution: say, every time you allocate a new
  repository object.  Or via after-gc-hook.

  (2) Whether an object is visible in the guardian is not a very
  deterministic property.  It won't be returned from a guardian until
  all other references are gone, but there's no guarantee about when it
  will be returned -- depends on GC and many other factors.  So it's
  possible that repository objects are still "alive" after you shut down

Why do you feel the need to "shut down" libgit?  Honestly I would punt.
Most other libraries aren't like that.


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