I'm curious what edge cases you know about or have bitten you with pickle. The main ones I know about are that it's not blazingly fast (though cPickle mitigates this a bit), and, as a possibly related issue, pickle actually uses multiple incompatible serialization protocols that are subject to change whenever a new Python version comes out.
It's also insecure in the sense that you can pickle and unpickle more or less arbitrary Python objects and object structures, so there's no way to trust a pickle from a source you don't control, unless you want to start down the rabbit hole of encrypting and signing your pickles. But that's actually never come up for me in practice.
The incompatibility issue has always been the bigger deal for me. You don't want to upgrade Python and then have to deal with converting all your model weights to a new serialization format, too. An unstable data interchange format is absolutely an oxymoron, and all but rules out the idea of using pickle in production for much of anything. The best use I can think of is for RPC between clients you control and trust, but I just can't bring myself to have that level of trust, even for a service or host that I'm sure is fully under my control.
TBH, my knowledge of pickle edge cases is limited to my colleague's recommendation. ChatGPT seems to be able to construct a plausible list that matches several of your points, but who knows if the rest was hallucinated.
It's also insecure in the sense that you can pickle and unpickle more or less arbitrary Python objects and object structures, so there's no way to trust a pickle from a source you don't control, unless you want to start down the rabbit hole of encrypting and signing your pickles. But that's actually never come up for me in practice.
The incompatibility issue has always been the bigger deal for me. You don't want to upgrade Python and then have to deal with converting all your model weights to a new serialization format, too. An unstable data interchange format is absolutely an oxymoron, and all but rules out the idea of using pickle in production for much of anything. The best use I can think of is for RPC between clients you control and trust, but I just can't bring myself to have that level of trust, even for a service or host that I'm sure is fully under my control.