bpo-33729: Fix issues with arguments parsing in hashlib. (GH-8346)

* help(hashlib) didn't work because of incorrect module name in blake2b and
  blake2s classes.
* Constructors blake2*(), sha3_*(), shake_*() and keccak_*() incorrectly
  accepted keyword argument "string" for binary data, but documented as
  accepting the "data" keyword argument. Now this parameter is positional-only.
* Keyword-only parameters in blake2b() and blake2s() were not documented as
  keyword-only.
* Default value for some parameters of blake2b() and blake2s() was None,
  which is not acceptable value.
* The length argument for shake_*.digest() was wrapped out to 32 bits.
* The argument for shake_128.digest() and shake_128.hexdigest() was not
  positional-only as intended.
* TypeError messages for incorrect arguments in all constructors sha3_*(),
  shake_*() and keccak_*() incorrectly referred to sha3_224.

Also made the following enhancements:

* More accurately specified input and result types for strings, bytes and
  bytes-like objects.
* Unified positional parameter names for update() and constructors.
* Improved formatting.

1 files changed, 13 insertions, 46 deletions

diff --git a/Modules/_sha3/clinic/sha3module.c.h b/Modules/_sha3/clinic/sha3module.c.h
index a1e80b0..b2a896e 100644
--- a/Modules/_sha3/clinic/sha3module.c.h
+++ b/Modules/_sha3/clinic/sha3module.c.h
@@ -2,33 +2,6 @@
 preserve
 [clinic start generated code]*/
 
-PyDoc_STRVAR(py_sha3_new__doc__,
-"sha3_224(string=None)\n"
-"--\n"
-"\n"
-"Return a new SHA3 hash object with a hashbit length of 28 bytes.");
-
-static PyObject *
-py_sha3_new_impl(PyTypeObject *type, PyObject *data);
-
-static PyObject *
-py_sha3_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
-{
-    PyObject *return_value = NULL;
-    static const char * const _keywords[] = {"string", NULL};
-    static _PyArg_Parser _parser = {"|O:sha3_224", _keywords, 0};
-    PyObject *data = NULL;
-
-    if (!_PyArg_ParseTupleAndKeywordsFast(args, kwargs, &_parser,
-        &data)) {
-        goto exit;
-    }
-    return_value = py_sha3_new_impl(type, data);
-
-exit:
-    return return_value;
-}
-
 PyDoc_STRVAR(_sha3_sha3_224_copy__doc__,
 "copy($self, /)\n"
 "--\n"
@@ -51,7 +24,7 @@ PyDoc_STRVAR(_sha3_sha3_224_digest__doc__,
 "digest($self, /)\n"
 "--\n"
 "\n"
-"Return the digest value as a string of binary data.");
+"Return the digest value as a bytes object.");
 
 #define _SHA3_SHA3_224_DIGEST_METHODDEF    \
     {"digest", (PyCFunction)_sha3_sha3_224_digest, METH_NOARGS, _sha3_sha3_224_digest__doc__},
@@ -84,36 +57,33 @@ _sha3_sha3_224_hexdigest(SHA3object *self, PyObject *Py_UNUSED(ignored))
 }
 
 PyDoc_STRVAR(_sha3_sha3_224_update__doc__,
-"update($self, obj, /)\n"
+"update($self, data, /)\n"
 "--\n"
 "\n"
-"Update this hash object\'s state with the provided string.");
+"Update this hash object\'s state with the provided bytes-like object.");
 
 #define _SHA3_SHA3_224_UPDATE_METHODDEF    \
     {"update", (PyCFunction)_sha3_sha3_224_update, METH_O, _sha3_sha3_224_update__doc__},
 
 PyDoc_STRVAR(_sha3_shake_128_digest__doc__,
-"digest($self, /, length)\n"
+"digest($self, length, /)\n"
 "--\n"
 "\n"
-"Return the digest value as a string of binary data.");
+"Return the digest value as a bytes object.");
 
 #define _SHA3_SHAKE_128_DIGEST_METHODDEF    \
-    {"digest", (PyCFunction)_sha3_shake_128_digest, METH_FASTCALL|METH_KEYWORDS, _sha3_shake_128_digest__doc__},
+    {"digest", (PyCFunction)_sha3_shake_128_digest, METH_O, _sha3_shake_128_digest__doc__},
 
 static PyObject *
 _sha3_shake_128_digest_impl(SHA3object *self, unsigned long length);
 
 static PyObject *
-_sha3_shake_128_digest(SHA3object *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+_sha3_shake_128_digest(SHA3object *self, PyObject *arg)
 {
     PyObject *return_value = NULL;
-    static const char * const _keywords[] = {"length", NULL};
-    static _PyArg_Parser _parser = {"k:digest", _keywords, 0};
     unsigned long length;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &length)) {
+    if (!PyArg_Parse(arg, "O&:digest", _PyLong_UnsignedLong_Converter, &length)) {
         goto exit;
     }
     return_value = _sha3_shake_128_digest_impl(self, length);
@@ -123,27 +93,24 @@ exit:
 }
 
 PyDoc_STRVAR(_sha3_shake_128_hexdigest__doc__,
-"hexdigest($self, /, length)\n"
+"hexdigest($self, length, /)\n"
 "--\n"
 "\n"
 "Return the digest value as a string of hexadecimal digits.");
 
 #define _SHA3_SHAKE_128_HEXDIGEST_METHODDEF    \
-    {"hexdigest", (PyCFunction)_sha3_shake_128_hexdigest, METH_FASTCALL|METH_KEYWORDS, _sha3_shake_128_hexdigest__doc__},
+    {"hexdigest", (PyCFunction)_sha3_shake_128_hexdigest, METH_O, _sha3_shake_128_hexdigest__doc__},
 
 static PyObject *
 _sha3_shake_128_hexdigest_impl(SHA3object *self, unsigned long length);
 
 static PyObject *
-_sha3_shake_128_hexdigest(SHA3object *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+_sha3_shake_128_hexdigest(SHA3object *self, PyObject *arg)
 {
     PyObject *return_value = NULL;
-    static const char * const _keywords[] = {"length", NULL};
-    static _PyArg_Parser _parser = {"k:hexdigest", _keywords, 0};
     unsigned long length;
 
-    if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
-        &length)) {
+    if (!PyArg_Parse(arg, "O&:hexdigest", _PyLong_UnsignedLong_Converter, &length)) {
         goto exit;
     }
     return_value = _sha3_shake_128_hexdigest_impl(self, length);
@@ -151,4 +118,4 @@ _sha3_shake_128_hexdigest(SHA3object *self, PyObject *const *args, Py_ssize_t na
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=a3aeb6c3b2fbd905 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=bf823532a7bffe68 input=a9049054013a1b77]*/