Fatal Python error: deallocating None

[Fredrik Lundh]

Gabriel Genellina wrote:

> Mmm, it appears that one of these C extensions isn't managing the ref 
> count correctly - perhaps there is a return Py_None without a previous 
> Py_INCREF? If None were returned in certain functions to indicate 
> failure or something exceptional - and not a regular condition - that 
> would explain that it doesn't fail very often.
> Unfortunately I don't know how to debug this - except by carefully 
> inspecting the C code :(

inserting

     print sys.getrefcount(None)

at strategic locations in your code will usually help you identify the
culprit.

(last time I stumbled upon this was in an earlier release of "sqlite",
which leaked one Py_None every time you connected to the database.  our
application contained a separate task that created it's own database
connection every 15:th minute or so, to calculate some statistics.  and
a fresh Python interpreter contains 500-600 references to Py_None...)

</F>