Hi Tim, On Mon, Dec 20, 2004 at 07:26:25PM -0500, Tim Peters wrote:
Still, it's a new-in-2.4 gimmick, and no pre-2.4 code could be using it. I suppose Armin found a use for it in 2.4, but I'm still scratching my head. If ZODB doesn't already depend on it, how useful can it be? QED
Some code in the 'py' lib used to use marshal to send simple objects between the main process and a subprocess. We ran into trouble when we extended the idea to a subprocess that would actually run via ssh on a remote machine, and the remote machine's Python version didn't match the local one. The obvious quick fix was to set the 'version' argument to 0 and pretend that it would be fine forever. Now that we essentially can't use this trick any more because of the 2.4.0 bug, we reverted to repr/eval, which is quite slower (and actually not guaranteed to work across Python versions either: string escapes sometimes change). We avoid to use cPickle because we want to be sure that only "simple enough" objects are sent over this way -- essentially nothing that depends on a precise Python module to be installed and identical on both machines. Armin