python bindings memory management

python bindings memory management

[Gaute Hope]

Hi,

when writing this small script [0][1] using the notmuch python bindings I 
had to manually delete the python objects in the right order. Otherwise 
it segfaults when exiting, presumably because memory dependencies / 
cleanup isn't done correctly when the Python GC gets going. Essentially 
I have to delete the objects in the order of their dependency:

```
  db = notmuch.Database()
  q = db.create_query ("some query")
  q.set_sort (notmuch.Query.SORT.OLDEST_FIRST) # probably not necessary
  msgs = q.search_messages ()


  for m in msgs:
    pass

  # remove these to get segfault
  del m
  del msgs
  del q

```

Regards, Gaute

[0] https://gist.github.com/gauteh/de546cb143ebae4a489a482a05ab4beb
[1] id:1507537566.y6qjbg4xoq.astroid@strange.none

Re: python bindings memory management

[David Bremner]

Gaute Hope <eg@gaute.vetsj.com> writes:

> Hi,
>
> when writing this small script [0][1] using the notmuch python bindings I 
> had to manually delete the python objects in the right order. Otherwise 
> it segfaults when exiting, presumably because memory dependencies / 
> cleanup isn't done correctly when the Python GC gets going. Essentially 
> I have to delete the objects in the order of their dependency:

Assuming this is python > 3.3, it sounds related to

     id:5694CA65.8010400@fastmail.net

See in particular

    id:20160112185107.GA21580@odin.tremily.us

Re: python bindings memory management

[Gaute Hope]

David Bremner writes on november 20, 2017 0:11:
> Gaute Hope <eg@gaute.vetsj.com> writes:
> 
>> Hi,
>>
>> when writing this small script [0][1] using the notmuch python bindings I 
>> had to manually delete the python objects in the right order. Otherwise 
>> it segfaults when exiting, presumably because memory dependencies / 
>> cleanup isn't done correctly when the Python GC gets going. Essentially 
>> I have to delete the objects in the order of their dependency:
> 
> Assuming this is python > 3.3, it sounds related to
> 
>      id:5694CA65.8010400@fastmail.net
> 
> See in particular
> 
>     id:20160112185107.GA21580@odin.tremily.us

Yep, probably the same thing.

- Gaute