Ulrich Eckhardt wrote:

Hi!

I'm looking at trunk/Python/sysmodule.c, function PySys_SetArgv(). In that function, there is code like this:

PyObject* path = PySys_GetObject("path"); ... if (path != NULL) { ... }

My intuition says that if path==NULL, something is very wrong. At least I would expect to get 'None', but never NULL, except when out of memory. So, for the case that path==NULL', I would simply invoke Py_FatalError("no mem for sys.path"), similarly to the other call there.

Sounds reasonable?

Uli

Maybe it's just being safe? From Python/sysmodule.c: PyThreadState *tstate = PyThreadState_GET(); PyObject *sd = tstate->interp->sysdict; if (sd == NULL) return NULL; return PyDict_GetItemString(sd, name); So if tstate->interp->sysdict is NULL, we return NULL. That's probably a bit unlikely. However, PyDict_GetItemString attempts to allocate a new PyString from the given char* key. If that fails, PySys_GetObject will also return NULL -- just like most functions in the code base that hit an out of memory error: PyObject * PyDict_GetItemString(PyObject *v, const char *key) { PyObject *kv, *rv; kv = PyString_FromString(key); if (kv == NULL) return NULL; rv = PyDict_GetItem(v, kv); Py_DECREF(kv); return rv; } Seems perfectly reasonable for it to return NULL in this situation. Cheers, T

Ulrich Eckhardt wrote:

Hi!

I'm looking at trunk/Python/sysmodule.c, function PySys_SetArgv(). In that function, there is code like this:

PyObject* path = PySys_GetObject("path"); ... if (path != NULL) { ... }

My intuition says that if path==NULL, something is very wrong. At least I would expect to get 'None', but never NULL, except when out of memory. So, for the case that path==NULL', I would simply invoke Py_FatalError("no mem for sys.path"), similarly to the other call there.

PySys_GetObject may return NULL after the user has removed sys.path with delattr(sys, 'path'). There are valid applications for removing sys.path. Christian

Ulrich Eckhardt wrote:

Hi!

I'm looking at trunk/Python/sysmodule.c, function PySys_SetArgv(). In that function, there is code like this:

PyObject* path = PySys_GetObject("path"); ... if (path != NULL) { ... }

My intuition says that if path==NULL, something is very wrong. At least I would expect to get 'None', but never NULL, except when out of memory. So, for the case that path==NULL', I would simply invoke Py_FatalError("no mem for sys.path"), similarly to the other call there.

Sounds reasonable?

Uli

Maybe it's just being safe? From Python/sysmodule.c: PyThreadState *tstate = PyThreadState_GET(); PyObject *sd = tstate->interp->sysdict; if (sd == NULL) return NULL; return PyDict_GetItemString(sd, name); So if tstate->interp->sysdict is NULL, we return NULL. That's probably a bit unlikely. However, PyDict_GetItemString attempts to allocate a new PyString from the given char* key. If that fails, PySys_GetObject will also return NULL -- just like most functions in the code base that hit an out of memory error: PyObject * PyDict_GetItemString(PyObject *v, const char *key) { PyObject *kv, *rv; kv = PyString_FromString(key); if (kv == NULL) return NULL; rv = PyDict_GetItem(v, kv); Py_DECREF(kv); return rv; } Seems perfectly reasonable for it to return NULL in this situation. Cheers, T

Ulrich Eckhardt wrote:

Hi!

I'm looking at trunk/Python/sysmodule.c, function PySys_SetArgv(). In that function, there is code like this:

PyObject* path = PySys_GetObject("path"); ... if (path != NULL) { ... }

My intuition says that if path==NULL, something is very wrong. At least I would expect to get 'None', but never NULL, except when out of memory. So, for the case that path==NULL', I would simply invoke Py_FatalError("no mem for sys.path"), similarly to the other call there.

PySys_GetObject may return NULL after the user has removed sys.path with delattr(sys, 'path'). There are valid applications for removing sys.path. Christian