SF bug [#470040] ParseTuple t# vs subclasses.
inherit_slots(): tp_as_buffer was getting inherited as if it were a
method pointer, rather than a pointer to a vector of method pointers. As
a result, inheriting from a type that implemented buffer methods was
ineffective, leaving all the tp_as_buffer slots NULL in the subclass.
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 1768a6d..e5ee591 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -2298,7 +2298,37 @@
pass
else:
raise TestFailed, "d.foo should be undefined now"
-
+
+def buffer_inherit():
+ import binascii
+ # SF bug [#470040] ParseTuple t# vs subclasses.
+ if verbose:
+ print "Testing that buffer interface is inherited ..."
+
+ class MyStr(str):
+ pass
+ base = 'abc'
+ m = MyStr(base)
+ # b2a_hex uses the buffer interface to get its argument's value, via
+ # PyArg_ParseTuple 't#' code.
+ vereq(binascii.b2a_hex(m), binascii.b2a_hex(base))
+
+ # It's not clear that unicode will continue to support the character
+ # buffer interface, and this test will fail if that's taken away.
+ class MyUni(unicode):
+ pass
+ base = u'abc'
+ m = MyUni(base)
+ vereq(binascii.b2a_hex(m), binascii.b2a_hex(base))
+
+ class MyInt(int):
+ pass
+ m = MyInt(42)
+ try:
+ binascii.b2a_hex(m)
+ raise TestFailed('subclass of int should not have a buffer interface')
+ except TypeError:
+ pass
def test_main():
class_docstrings()
@@ -2347,6 +2377,7 @@
copies()
binopoverride()
subclasspropagation()
+ buffer_inherit()
if verbose: print "All OK"
if __name__ == "__main__":
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index ced80ec..a498f0f 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -1657,6 +1657,7 @@
#define COPYNUM(SLOT) COPYSLOT(tp_as_number->SLOT)
#define COPYSEQ(SLOT) COPYSLOT(tp_as_sequence->SLOT)
#define COPYMAP(SLOT) COPYSLOT(tp_as_mapping->SLOT)
+#define COPYBUF(SLOT) COPYSLOT(tp_as_buffer->SLOT)
/* This won't inherit indirect slots (from tp_as_number etc.)
if type doesn't provide the space. */
@@ -1732,6 +1733,16 @@
COPYMAP(mp_ass_subscript);
}
+ if (type->tp_as_buffer != NULL && base->tp_as_buffer != NULL) {
+ basebase = base->tp_base;
+ if (basebase->tp_as_buffer == NULL)
+ basebase = NULL;
+ COPYBUF(bf_getreadbuffer);
+ COPYBUF(bf_getwritebuffer);
+ COPYBUF(bf_getsegcount);
+ COPYBUF(bf_getcharbuffer);
+ }
+
basebase = base->tp_base;
COPYSLOT(tp_dealloc);
@@ -1749,7 +1760,6 @@
/* tp_hash see tp_richcompare */
COPYSLOT(tp_call);
COPYSLOT(tp_str);
- COPYSLOT(tp_as_buffer);
if (type->tp_flags & base->tp_flags & Py_TPFLAGS_HAVE_RICHCOMPARE) {
if (type->tp_compare == NULL &&
type->tp_richcompare == NULL &&