[Python-Dev] interning

[Guido van Rossum]

> > $ ./python ../Lib/test/regrtest.py -l test_gc
> > test_gc
> > Warning: test created 20 uncollectable object(s).
> > 1 test OK.

[Neil S]
> Something weird is going on.  This patch fixes test_finalizer_newclass: 
> 
> --- Lib/test/test_gc.py 9 Aug 2002 17:38:16 -0000       1.19
> +++ Lib/test/test_gc.py 10 Aug 2002 18:33:47 -0000
> @@ -147,6 +147,8 @@
>      else:
>          raise TestFailed, "didn't find obj in garbage (finalizer)"
>      gc.garbage.remove(obj)
> +    del A, B, obj
> +    gc.collect() # finds 13 objects!
> 
> 
> I guess there is a reference cycle there that wasn't there before.
> Could it have something to do with tp_del?

I don't think so -- a Python of a month old had the same warnings when
I added these tests that use new-style class.

It's much simpler than this: new-style classes have cyclical
references to themselves that must be collected.  It so happened that
the saveall test was fooled by these.  Tim checked in a fix that
prevents this.

--Guido van Rossum (home page: http://www.python.org/~guido/)