using a custom, nearly-identical macro. This probably changes how some of
these functions are compiled, which may result in fractionally slower (or
faster) execution. Considering the nature of traversal, visiting much of the
address space in unpredictable patterns, I'd argue the code readability and
maintainability is well worth it ;P
In C++, it's an error to pass a string literal to a char* function
without a const_cast(). Rather than require every C++ extension
module to put a cast around string literals, fix the API to state the
const-ness.
I focused on parts of the API where people usually pass literals:
PyArg_ParseTuple() and friends, Py_BuildValue(), PyMethodDef, the type
slots, etc. Predictably, there were a large set of functions that
needed to be fixed as a result of these changes. The most pervasive
change was to make the keyword args list passed to
PyArg_ParseTupleAndKewords() to be a const char *kwlist[].
One cast was required as a result of the changes: A type object
mallocs the memory for its tp_doc slot and later frees it.
PyTypeObject says that tp_doc is const char *; but if the type was
created by type_new(), we know it is safe to cast to char *.
SF bug [ 751276 ] cPickle doesn't raise error, pickle does (recursiondepth)
Most of the calls to PyErr_Clear() were intended to catch & clear an
attribute error and try something different. Guard all those cases
with a PyErr_ExceptionMatches() and fail if some other error
occurred. The other error is likely a bug in the user code.
This is basically the C equivalent of changing "except:" to
"except AttributeError:"
tp_free is NULL or PyObject_Del at the end. Because it's a base type
it must call tp_free in its dealloc function, and because it's gc'able
it must not call PyObject_Del.
inherit_slots(): Don't inherit tp_free unless the type and its base
agree about whether they're gc'able. If the type is gc'able and the
base is not, and the base uses the default PyObject_Del for its
tp_free, give the type PyObject_GC_Del for its tp_free (the appropriate
default for a gc'able type).
cPickle.c: The Pickler and Unpickler types claim to be base classes
and gc'able, but their dealloc functions didn't call tp_free.
Repaired that. Also call PyType_Ready() on these typeobjects, so
that the correct (PyObject_GC_Del) default memory-freeing function
gets plugged into these types' tp_free slots.
pack_float, pack_double, save_float: All the routines for creating
IEEE-format packed representations of floats and doubles simply ignored
that rounding can (in rare cases) propagate out of a long string of
1 bits. At worst, the end-off carry can (by mistake) interfere with
the exponent value, and then unpacking yields a result wrong by a factor
of 2. In less severe cases, it can end up losing more low-order bits
than intended, or fail to catch overflow *caused* by rounding.
Bugfix candidate, but I already backported this to 2.2.
In 2.3, this code remains in severe need of refactoring.
reasons: importing module can fail, or the attribute lookup
module.name can fail. We were giving the same error msg for
both cases, making it needlessly hard to guess what went wrong.
These cases give different error msgs now.
the optional proto 2 slot state.
pickle.py, load_build(): CAUTION: Noted that cPickle's
load_build and pickle's load_build really don't do the same
things with the state, and didn't before this patch either.
cPickle never tries to do .update(), and has no backoff if
instance.__dict__ can't be retrieved. There are no tests
that can tell the difference, and part of what cPickle's
load_build() did looked accidental to me, so I don't know
what the true intent is here.
pickletester.py, test_pickle.py: Got rid of the hack for
exempting cPickle from running some of the proto 2 tests.
dictobject.c, PyDict_Next(): documented intended use.
exercised by the test suite before cPickle knows how to create NEWOBJ
too. For now, it was just tried once by hand (via loading a NEWOBJ
pickle created by pickle.py).
guarantee to keep valid pointers in its slots.
tests: Moved ExtensionSaver from test_copy_reg into pickletester, and
use it both places. Once extension codes get assigned, it won't be
safe to overwrite them willy nilly in test suites, and ExtensionSaver
does a thorough job of undoing any possible damage.
Beefed up the EXT[124] tests a bit, to check the smallest and largest
codes in each opcode's range too.
this clarifies that they are part of an internal API (albeit shared
between pickle.py, copy_reg.py and cPickle.c).
I'd like to do the same for copy_reg.dispatch_table, but worry that it
might be used by existing code. This risk doesn't exist for the
extension registry.
because it seems more consistent with the rest of the code.
cPickle_PyMapping_HasKey(): This extern function isn't used anywhere in
Python or Zope, so got rid of it.
readability.
load_bool(): Now that I know the intended difference between _PUSH and
_APPEND, used the right one.
Pdata_grow(): Squashed out a redundant overflow test.
a function, then
p->f(arg1, arg2, ...)
is semantically the same as
(*p->f)(arg1, arg2, ...)
Changed all instances of the latter into the former. Given how often
the code embeds this kind of expression in an if test, the unnecessary
parens and dereferening operator were a real drag on readability.
loops. Renamed DATA and BINDATA to DATA0 and DATA1. Included
disassemblies, but noted why we can't test them. Added XXX comment to
cPickle about a mysterious comment, where pickle and cPickle diverge
in how they number PUT indices.
Georg Brandl
Thomas Wouters
Neal Norwitz
Martin v. Löwis
Jeremy Hylton
Raymond Hettinger
Christian Tismer
Tim Peters
Guido van Rossum