Update the hashlib brain hash.digest & hash.hexdigest met…

…hods. (#1827)

* Add the ``length`` parameter to ``hash.digest`` & ``hash.hexdigest`` in the ``hashlib`` brain.

* Move content in Changelog to a different section.

Refs pylint-dev/pylint#4039

ChangeLog

@@ -20,6 +20,10 @@ What's New in astroid 2.12.12?
 ==============================
 Release date: TBA
 
+* Add the ``length`` parameter to ``hash.digest`` & ``hash.hexdigest`` in the ``hashlib`` brain.
+
+  Refs PyCQA/pylint#4039
+
 
 
 What's New in astroid 2.12.11?

astroid/brain/brain_hashlib.py

@@ -10,48 +10,86 @@
 
 def _hashlib_transform():
     maybe_usedforsecurity = ", usedforsecurity=True" if PY39_PLUS else ""
-    signature = f"value=''{maybe_usedforsecurity}"
+    init_signature = f"value=''{maybe_usedforsecurity}"
+    digest_signature = "self"
+    shake_digest_signature = "self, length"
+
     template = """
-    class %(name)s(object):
-      def __init__(self, %(signature)s): pass
-      def digest(self):
-        return %(digest)s
-      def copy(self):
-        return self
-      def update(self, value): pass
-      def hexdigest(self):
-        return ''
-      @property
-      def name(self):
-        return %(name)r
-      @property
-      def block_size(self):
-        return 1
-      @property
-      def digest_size(self):
-        return 1
+    class %(name)s:
+        def __init__(self, %(init_signature)s): pass
+        def digest(%(digest_signature)s):
+            return %(digest)s
+        def copy(self):
+            return self
+        def update(self, value): pass
+        def hexdigest(%(digest_signature)s):
+            return ''
+        @property
+        def name(self):
+            return %(name)r
+        @property
+        def block_size(self):
+            return 1
+        @property
+        def digest_size(self):
+            return 1
     """
+
     algorithms_with_signature = dict.fromkeys(
-        ["md5", "sha1", "sha224", "sha256", "sha384", "sha512"], signature
+        [
+            "md5",
+            "sha1",
+            "sha224",
+            "sha256",
+            "sha384",
+            "sha512",
+            "sha3_224",
+            "sha3_256",
+            "sha3_384",
+            "sha3_512",
+        ],
+        (init_signature, digest_signature),
+    )
+
+    blake2b_signature = (
+        "data=b'', *, digest_size=64, key=b'', salt=b'', "
+        "person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, "
+        f"node_depth=0, inner_size=0, last_node=False{maybe_usedforsecurity}"
+    )
+
+    blake2s_signature = (
+        "data=b'', *, digest_size=32, key=b'', salt=b'', "
+        "person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, "
+        f"node_depth=0, inner_size=0, last_node=False{maybe_usedforsecurity}"
     )
-    blake2b_signature = f"data=b'', *, digest_size=64, key=b'', salt=b'', \
-            person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, \
-            node_depth=0, inner_size=0, last_node=False{maybe_usedforsecurity}"
-    blake2s_signature = f"data=b'', *, digest_size=32, key=b'', salt=b'', \
-            person=b'', fanout=1, depth=1, leaf_size=0, node_offset=0, \
-            node_depth=0, inner_size=0, last_node=False{maybe_usedforsecurity}"
-    new_algorithms = dict.fromkeys(
-        ["sha3_224", "sha3_256", "sha3_384", "sha3_512", "shake_128", "shake_256"],
-        signature,
+
+    shake_algorithms = dict.fromkeys(
+        ["shake_128", "shake_256"],
+        (init_signature, shake_digest_signature),
     )
-    algorithms_with_signature.update(new_algorithms)
+    algorithms_with_signature.update(shake_algorithms)
+
     algorithms_with_signature.update(
-        {"blake2b": blake2b_signature, "blake2s": blake2s_signature}
+        {
+            "blake2b": (blake2b_signature, digest_signature),
+            "blake2s": (blake2s_signature, digest_signature),
+        }
     )
+
     classes = "".join(
-        template % {"name": hashfunc, "digest": 'b""', "signature": signature}
-        for hashfunc, signature in algorithms_with_signature.items()
+        template
+        % {
+            "name": hashfunc,
+            "digest": 'b""',
+            "init_signature": init_signature,
+            "digest_signature": digest_signature,
+        }
+        for hashfunc, (
+            init_signature,
+            digest_signature,
+        ) in algorithms_with_signature.items()
     )
+
     return parse(classes)
 
 

tests/unittest_brain.py

@@ -83,24 +83,44 @@ def _assert_hashlib_class(self, class_obj: ClassDef) -> None:
             len(class_obj["__init__"].args.defaults), 2 if PY39_PLUS else 1
         )
         self.assertEqual(len(class_obj["update"].args.args), 2)
-        self.assertEqual(len(class_obj["digest"].args.args), 1)
-        self.assertEqual(len(class_obj["hexdigest"].args.args), 1)
 
     def test_hashlib(self) -> None:
         """Tests that brain extensions for hashlib work."""
         hashlib_module = MANAGER.ast_from_module_name("hashlib")
-        for class_name in ("md5", "sha1"):
+        for class_name in (
+            "md5",
+            "sha1",
+            "sha224",
+            "sha256",
+            "sha384",
+            "sha512",
+            "sha3_224",
+            "sha3_256",
+            "sha3_384",
+            "sha3_512",
+        ):
             class_obj = hashlib_module[class_name]
             self._assert_hashlib_class(class_obj)
+            self.assertEqual(len(class_obj["digest"].args.args), 1)
+            self.assertEqual(len(class_obj["hexdigest"].args.args), 1)
 
-    def test_hashlib_py36(self) -> None:
+    def test_shake(self) -> None:
+        """Tests that the brain extensions for the hashlib shake algorithms work."""
         hashlib_module = MANAGER.ast_from_module_name("hashlib")
-        for class_name in ("sha3_224", "sha3_512", "shake_128"):
+        for class_name in ("shake_128", "shake_256"):
             class_obj = hashlib_module[class_name]
             self._assert_hashlib_class(class_obj)
+            self.assertEqual(len(class_obj["digest"].args.args), 2)
+            self.assertEqual(len(class_obj["hexdigest"].args.args), 2)
+
+    def test_blake2(self) -> None:
+        """Tests that the brain extensions for the hashlib blake2 hash functions work."""
+        hashlib_module = MANAGER.ast_from_module_name("hashlib")
         for class_name in ("blake2b", "blake2s"):
             class_obj = hashlib_module[class_name]
             self.assertEqual(len(class_obj["__init__"].args.args), 2)
+            self.assertEqual(len(class_obj["digest"].args.args), 1)
+            self.assertEqual(len(class_obj["hexdigest"].args.args), 1)
 
 
 class CollectionsDequeTests(unittest.TestCase):