RecursionError when pickle dump/loading dxf file

[zassoulin]

Describe the bug
when running pickle load/dump on a dxf object (ezdxf.document.Drawing) an RecursionError: maximum recursion depth exceeded is recived.

To Reproduce
Information and data needed to reproduce the error:
read a dxf file and try to dump it into a file using pickle, i saved the file and read it as gzip.
when trying to load the saved file a RecursionError occures.

Expected behavior
the dxf object should be loaded correctly.
Screenshots
inorder to replecate the problem i have created a small notebook for it with a random dxf i found online.

EzdxfRecursionErrorNotebook.zip

[mozman]

Pickle protocol is not supported!

[mbway]

ezdxf.document.Drawing is an in-memory representation of a DXF file, so dxf seems like it would be an appropriate storage format rather than a pickled ezdxf object.

If pickle as a format is a hard requirement you can pickle a string containing the contents of a DXF file?

[zassoulin]

pickle is not a hard requirement but i need to read alot of dxf files in a short amount of time and reading&parsing a dxf file takes significantly longer than using pickle(the same dxf file will be read multiple times), thus the whole idea of using pickle came to be.
thanks alot for the response and if you have any idea/suggestion about how might i tackle the issue i would love to hear it

[mbway]

fair enough. I opened a PR that hopefully works for you #1232