[Python-Dev] Re:import.c (original) (raw)

Wiktor Sadowski art at wiktorsadowski.com
Sat May 29 15:46:42 EDT 2004

Circular import cases could be detected by adding an int "state" field (initialized to 0 in PyModule_New) to the module object and PyModule_GetState/PyModule_SetState api functions to access the field.

Then: in load_module (import.c) set the state to 1 ,when a module is completly loaded: /just before return/ if(m) PyModule_SetState(m,1) return m;

in import_from (ceval.c): if (x == NULL && PyErr_ExceptionMatches(PyExc_AttributeError)) { if(!PyModule_GetState(v)) /raise the error and warn against circular import/ else /default error/

the same in PyGeneric_GetAttr (object.c): /* before raising an error*/ if(PyModule_Check(obj) && !PyModule_GetState(obj)) /add a circular import warning to the error string/ else /default error/

Probably there are some other places where modules state should be changed or checked but the solution I am proposing would help to localize most of them;

A module's dict could be used to mark it's state but in my opinion an additional field is much safer (the same applays to PyModule_GetState/PyModule_SetState vs a new member def)

Also: the soluton would enable checking for partially-loaded/broken modules in system.modules dict.

Regards, Wiktor Sadowski

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