[Python-Dev] id() on Win64 (was: CVS: python/dist/src/Python bltinmodule.c,2.162,2.163)

[Barry A. Warsaw]

>>>>> "TP" == Tim Peters <tim_one@email.msn.com> writes:

    TP> Well, neither Java's hashCode nor identityHashCode are correct
    TP> implementations of Python's id(), so JPython's id() is simply
    TP> wrong.  I don't know anything about the internals of JPython.
    TP> If there's a "choke point" for allocating Python objects, the
    TP> quickest way out may be to add a write-once "id" field to each
    TP> Python object under JPython, and simply fill it with an
    TP> integer that's (safely) incremented by 1 on each allocation.

    TP> Python doesn't guarantee you'll get the *same* id(x) across
    TP> implementations, or even across runs under a single
    TP> implementation, so the implementations of id() in CPython and
    TP> JPython can do entirely different things.  They have to meet
    TP> the promises in the Python docs, though, and JPython's
    TP> currently doesn't.

I can't generate patches right now, but what you need to change is in
__builtin__.java, the id() function.  It should probably call
object.id() which would fill in the monotonically incrementing id as
Tim suggestions.

One question is what to do about Java proxies.  Currently built-in
id() returns the identityHashCode() of the proxy object, which is just
an Object.  I'm not sure sticking the id in the wrapper is the right
thing or not.

-Barry