If a new exception occurs while an exception instance is being
created, try harder to make sure there is a traceback. If the
original exception had a traceback associated with it and the new
exception does not, keep the old exception.
Of course, callers to PyErr_NormalizeException() must still be
prepared to have tb set to NULL.
XXX This isn't an ideal solution, but it's better than no traceback at
all. It occurs if, for example, the exception occurs when the call to
the constructor fails before any Python code is executed. Guido
suggests that it there is Python code that was about to be executed
-- but wasn't, say, because it was called with the wrong number of
arguments -- then we should point at the first line of the code object
anyway.
in release builds. Suggested by Martin v. Loewis.
I'm half tempted to macroize PyErr_Occurred too, as the whole thing could
collapse to just
_PyThreadState_Current->curexc_type
for errors raised in future.c.
Move some helper functions from compile.c to errors.c and make them
API functions: PyErr_SyntaxLocation() and PyErr_ProgramText().
return 0 (exceptions don't match). This means that if an ImportError
is raised because exceptions.py can't be imported, the interpreter
will exit "cleanly" with an error message instead of just core
dumping.
PyErr_SetFromErrnoWithFilename(), PyErr_SetFromWindowsErrWithFilename():
Don't test on Py_UseClassExceptionsFlag.
* Changes to a recent patch by Chris Tismer to errors.c. Chris' patch
always used FormatMessage() to get the error message passing the error code
from errno - but errno and FormatMessage use a different numbering scheme.
The main reason the patch looked OK was that ENOFILE==ERROR_FILE_NOT_FOUND -
but that is about the only shared error code :-). The MS CRT docs tell you
to use _sys_errlist()/_sys_nerr. My patch does also this, and adds a very
similar function specifically for win32 error codes.
