This is a topic which comes up now and then but which hasn't been
resolved so far.
Sage has a "pickle jar" stored in src/ext/pickle_jar/pickle_jar.tar.bz2
and there are tests in src/sage/structure/sage_object.pyx which check
that every object in the pickle jar can be unpickled without raising an
exception.
The theory is that this ensures that people having old pickles on their
machines can still use them with newer versions of Sage. However, the
pickle jar does not achieve this goal because
(1) The doctest only tests that the pickles can be unpickled. There are
no tests that the unpickled objects still function correctly. See
https://trac.sagemath.org/ticket/16311
(2) Nobody adds new pickles to the pickle jar. The last time that a
pickle was added was in 2011. So, if anything, it only tests that
pickles which are at least 6 years old still work correctly.
Since the pickle jar doesn't do what it is meant to do, I suggest to be
pragmatic and remove it completely.
Having the pickle jar is a burden for development because it prevents
certain refactorings or removals. For example finite_field_ext_pari.py
was deprecated in 2014 but we cannot remove it because it breaks the
pickle jar. I know that I could probably fix this with
register_unpickle_override() but that feels a waste of time because I
wonder if anybody really cares. In the mean time, people need to
maintain that unused deprecated file to make it Python 3 compatible for
example.
I'm sure that some people have suggestions for improving the pickle jar
procedure. But still, the fact remains that many pickles in the current
pickle jar are broken. So there is no point in keeping them.
Thoughts?
Jeroen.
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at https://groups.google.com/group/sage-devel.
For more options, visit https://groups.google.com/d/optout.
