Backport for issue1265 (pdb bug with "with" statement). When an unfinished generator-iterator is garbage collected, PyEval_EvalFrameEx is called with a GeneratorExit exception set. This leads to funny results if the sys.settrace function itself makes use of generators. A visible effect is that the settrace function is reset to None. Another is that the eventual "finally" block of the generator is not called. It is necessary to save/restore the exception around the call to the trace function. This happens a lot with py3k: isinstance() of an ABCMeta instance runs def __instancecheck__(cls, instance): """Override for isinstance(instance, cls).""" return any(cls.__subclasscheck__(c) for c in {instance.__class__, type(instance)}) which lets an opened generator expression each time it returns True. And the problem can be reproduced in 2.5 with pure python code.

/* Subroutine to get the last modification time of a file */

/* (A separate file because this may be OS dependent) */

#include "Python.h"
#include "pyconfig.h"

#ifdef __cplusplus
extern "C" {
#endif

time_t
PyOS_GetLastModificationTime(char *path, FILE *fp)
{
	struct stat st;
	if (fstat(fileno(fp), &st) != 0)
		return -1;
	else
		return st.st_mtime;
}

#ifdef __cplusplus
}
#endif