diff options
Diffstat (limited to 'Objects/object.c')
| -rw-r--r-- | Objects/object.c | 82 |
1 files changed, 67 insertions, 15 deletions
diff --git a/Objects/object.c b/Objects/object.c index b1bf2c3..3207d8a 100644 --- a/Objects/object.c +++ b/Objects/object.c @@ -353,6 +353,46 @@ PyObject_Unicode(PyObject *v) #endif +/* Helper to warn about deprecated tp_compare return values. Return: + -2 for an exception; + -1 if v < w; + 0 if v == w; + 1 if v > w. + (This function cannot return 2.) +*/ +static int +adjust_tp_compare(int c) +{ + if (PyErr_Occurred()) { + if (c != -1 && c != -2) { + PyObject *t, *v, *tb; + PyErr_Fetch(&t, &v, &tb); + if (PyErr_Warn(PyExc_RuntimeWarning, + "tp_compare didn't return -1 or -2 " + "for exception") < 0) { + Py_XDECREF(t); + Py_XDECREF(v); + Py_XDECREF(tb); + } + else + PyErr_Restore(t, v, tb); + } + return -2; + } + else if (c < -1 || c > 1) { + if (PyErr_Warn(PyExc_RuntimeWarning, + "tp_compare didn't return -1, 0 or 1") < 0) + return -2; + else + return c < -1 ? -1 : 1; + } + else { + assert(c >= -1 && c <= 1); + return c; + } +} + + /* Macro to get the tp_richcompare field of a type if defined */ #define RICHCOMPARE(t) (PyType_HasFeature((t), Py_TPFLAGS_HAVE_RICHCOMPARE) \ ? (t)->tp_richcompare : NULL) @@ -480,9 +520,7 @@ try_3way_compare(PyObject *v, PyObject *w) /* If both have the same (non-NULL) tp_compare, use it. */ if (f != NULL && f == w->ob_type->tp_compare) { c = (*f)(v, w); - if (c < 0 && PyErr_Occurred()) - return -1; - return c < 0 ? -1 : c > 0 ? 1 : 0; + return adjust_tp_compare(c); } /* If either tp_compare is _PyObject_SlotCompare, that's safe. */ @@ -502,9 +540,7 @@ try_3way_compare(PyObject *v, PyObject *w) c = (*f)(v, w); Py_DECREF(v); Py_DECREF(w); - if (c < 0 && PyErr_Occurred()) - return -2; - return c < 0 ? -1 : c > 0 ? 1 : 0; + return adjust_tp_compare(c); } /* Try w's comparison, if defined */ @@ -512,9 +548,11 @@ try_3way_compare(PyObject *v, PyObject *w) c = (*f)(w, v); /* swapped! */ Py_DECREF(v); Py_DECREF(w); - if (c < 0 && PyErr_Occurred()) - return -2; - return c < 0 ? 1 : c > 0 ? -1 : 0; /* negated! */ + c = adjust_tp_compare(c); + if (c >= -1) + return -c; /* Swapped! */ + else + return c; } /* No comparison defined */ @@ -591,11 +629,11 @@ default_3way_compare(PyObject *v, PyObject *w) #define CHECK_TYPES(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_CHECKTYPES) /* Do a 3-way comparison, by hook or by crook. Return: - -2 for an exception; + -2 for an exception (but see below); -1 if v < w; 0 if v == w; 1 if v > w; - If the object implements a tp_compare function, it returns + BUT: if the object implements a tp_compare function, it returns whatever this function returns (whether with an exception or not). */ static int @@ -607,9 +645,22 @@ do_cmp(PyObject *v, PyObject *w) if (v->ob_type == w->ob_type && (f = v->ob_type->tp_compare) != NULL) { c = (*f)(v, w); - if (c != 2 || !PyInstance_Check(v)) - return c; - } + if (PyInstance_Check(v)) { + /* Instance tp_compare has a different signature. + But if it returns undefined we fall through. */ + if (c != 2) + return c; + /* Else fall throug to try_rich_to_3way_compare() */ + } + else + return adjust_tp_compare(c); + } + /* We only get here if one of the following is true: + a) v and w have different types + b) v and w have the same type, which doesn't have tp_compare + c) v and w are instances, and either __cmp__ is not defined or + __cmp__ returns NotImplemented + */ c = try_rich_to_3way_compare(v, w); if (c < 2) return c; @@ -902,7 +953,8 @@ PyObject_RichCompare(PyObject *v, PyObject *w, int op) fcmp = v->ob_type->tp_compare; if (fcmp != NULL) { int c = (*fcmp)(v, w); - if (c < 0 && PyErr_Occurred()) { + c = adjust_tp_compare(c); + if (c == -2) { res = NULL; goto Done; } |