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, 6 insertions, 2 deletions

diff --git a/Modules/_hashopenssl.c b/Modules/_hashopenssl.c
index b6dcc06..40cd632 100644
--- a/Modules/_hashopenssl.c
+++ b/Modules/_hashopenssl.c
@@ -729,6 +729,10 @@ pbkdf2_hmac(PyObject *self, PyObject *args, PyObject *kwdict)
 #if OPENSSL_VERSION_NUMBER > 0x10100000L && !defined(OPENSSL_NO_SCRYPT) && !defined(LIBRESSL_VERSION_NUMBER)
 #define PY_SCRYPT 1
 
+/* XXX: Parameters salt, n, r and p should be required keyword-only parameters.
+   They are optional in the Argument Clinic declaration only due to a
+   limitation of PyArg_ParseTupleAndKeywords. */
+
 /*[clinic input]
 _hashlib.scrypt
 
@@ -858,13 +862,13 @@ _hashlib.hmac_digest
     msg: Py_buffer
     digest: str
 
-Single-shot HMAC
+Single-shot HMAC.
 [clinic start generated code]*/
 
 static PyObject *
 _hashlib_hmac_digest_impl(PyObject *module, Py_buffer *key, Py_buffer *msg,
                           const char *digest)
-/*[clinic end generated code: output=75630e684cdd8762 input=10e964917921e2f2]*/
+/*[clinic end generated code: output=75630e684cdd8762 input=562d2f4249511bd3]*/
 {
     unsigned char md[EVP_MAX_MD_SIZE] = {0};
     unsigned int md_len = 0;