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Um, I thought I'd already checked this in.

Browse source 
Anyway, this is the changes to the with-statement
so that __exit__ must return a true value in order
for a pending exception to be ignored.
The PEP (343) is already updated.
This commit is contained in:
Guido van Rossum 2006-03-10 02:28:35 +00:00
parent 692cdbc5d6
commit f669436189
11 changed files with 61 additions and 106 deletions
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49
Python/ceval.c
View file

@ -2189,48 +2189,51 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throw)
Below that are 1-3 values indicating how/why
we entered the finally clause:
- SECOND = None
- (SECOND, THIRD) = (WHY_RETURN or WHY_CONTINUE), retval
- (SECOND, THIRD) = (WHY_{RETURN,CONTINUE}), retval
- SECOND = WHY_*; no retval below it
- (SECOND, THIRD, FOURTH) = exc_info()
In the last case, we must call
TOP(SECOND, THIRD, FOURTH)
otherwise we must call
TOP(None, None, None)
but we must preserve the stack entries below TOP.
The code here just sets the stack up for the call;
separate CALL_FUNCTION(3) and POP_TOP opcodes are
emitted by the compiler.
In addition, if the stack represents an exception,
we "zap" this information; __exit__() should
re-raise the exception if it wants to, and if
__exit__() returns normally, END_FINALLY should
*not* re-raise the exception. (But non-local
gotos should still be resumed.)
*and* the function call returns a 'true' value, we
"zap" this information, to prevent END_FINALLY from
re-raising the exception. (But non-local gotos
should still be resumed.)
*/
x = TOP();
u = SECOND();
if (PyInt_Check(u) || u == Py_None) {
u = v = w = Py_None;
Py_INCREF(u);
Py_INCREF(v);
Py_INCREF(w);
}
else {
v = THIRD();
w = FOURTH();
/* Zap the exception from the stack,
to fool END_FINALLY. */
STACKADJ(-2);
SET_TOP(x);
Py_INCREF(Py_None);
SET_SECOND(Py_None);
}
STACKADJ(3);
SET_THIRD(u);
SET_SECOND(v);
SET_TOP(w);
/* XXX Not the fastest way to call it... */
x = PyObject_CallFunctionObjArgs(x, u, v, w, NULL);
if (x == NULL)
break; /* Go to error exit */
if (u != Py_None && PyObject_IsTrue(x)) {
/* There was an exception and a true return */
Py_DECREF(x);
x = TOP(); /* Again */
STACKADJ(-3);
Py_INCREF(Py_None);
SET_TOP(Py_None);
Py_DECREF(x);
Py_DECREF(u);
Py_DECREF(v);
Py_DECREF(w);
} else {
/* Let END_FINALLY do its thing */
Py_DECREF(x);
x = POP();
Py_DECREF(x);
}
break;
}