[Python-Dev] CPython crash with '%o'

[Christian Heimes]

Mike Stall wrote:
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> SystemError: \loewis\25\python\Objects\stringobject.c:4236: bad argument to internal function
> Note that if c derives from 'int' instead of 'long', everything works as expected.

I'm able to reproduce the error with Python 2.5.1 and 2.5 svn on Linux.
It also happens when I overwrite __hex__ and do "%x" % c(5) for
subclasses of long but not for subclasses from int.

class c(long):
    def __hex__(self):
        return "100"
    def __oct__(self):
        return "100"

>>> x = c(5)
>>> hex(x)
'100'
>>> oct(x)
'100'
>>> "%o" % x
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
SystemError: Objects/stringobject.c:4269: bad argument to internal function
>>> "%x" % x
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
SystemError: Objects/stringobject.c:4269: bad argument to internal function

Objects/stringobject.c:_PyString_FormatLong(...)
	...
        /* To modify the string in-place, there can only be one
reference. */
        if (result->ob_refcnt != 1) {
                PyErr_BadInternalCall();
                return NULL;
        }
	...
Christian