Re: Python binding SIGABRT/SIGSEGV

[Michael J Gruber <git@grubix.eu>]

Austin Lund venit, vidit, dixit 2022-02-10 06:56:12:
> I'm clearly doing this python code wrong by not using the iterator correctly:
> 
> > import notmuch2
> > 
> > d = notmuch2.Database()
> > m = list(d.messages("since:today"))
> > p = m[0].path
> > print(p)
> 
> But I seem to be getting a SIGABRT instead of a python stack trace.  Is
> this the expected behaviour?

You didn't expect it :)

And this can be confusing. d.messages() returns an iterator through
Message objects whose lifetime depends on the iterator. In contrast,
thread.get_messages() returns on iterator through OwnedMessage objects
whose lifetime depends on the thread.

As soon as the iterator is depleted, the returned objects are (possibly)
gone. (Well, because it's return by reference in Python, and ...)

If you're interested in m[0] only you can "cheat" by not depleting the
iterator:

mm = next(d.messages("since:today"))

p = mm.path

This never frees the object (I think).

My attempts with notmuch2._message.OwnedMessage (and db as parent)
failed. There must be a better way, possibly using a context manager or
search.

I guess usually people just use the iterator in a for loop and do
something with the message inside the loop (while the iterator is not
depleted), such as converting it into a proper email.Message object
(i.e. instantiating a new object from it).

Michael