python · methane · Apr 9, 2019 · May 11, 2018 · Apr 9, 2019 · Apr 9, 2019
diff --git a/Doc/library/json.rst b/Doc/library/json.rst
@@ -265,18 +265,21 @@ Basic Usage
      *fp* can now be a :term:`binary file`. The input encoding should be
      UTF-8, UTF-16 or UTF-32.

-.. function:: loads(s, *, encoding=None, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw)
+.. function:: loads(s, *, cls=None, object_hook=None, parse_float=None, parse_int=None, parse_constant=None, object_pairs_hook=None, **kw)

   Deserialize *s* (a :class:`str`, :class:`bytes` or :class:`bytearray`
   instance containing a JSON document) to a Python object using this
   :ref:`conversion table <json-to-py-table>`.

   The other arguments have the same meaning as in :func:`load`, except
-   *encoding* which is ignored and deprecated.
+   *encoding* which is ignored and deprecated since Python 3.1.

   If the data being deserialized is not a valid JSON document, a
   :exc:`JSONDecodeError` will be raised.

+   .. deprecated-removed:: 3.1 3.9
+      *encoding* keyword argument.
+
   .. versionchanged:: 3.6
      *s* can now be of type :class:`bytes` or :class:`bytearray`. The
      input encoding should be UTF-8, UTF-16 or UTF-32.

diff --git a/Lib/json/__init__.py b/Lib/json/__init__.py
@@ -296,7 +296,7 @@ def load(fp, *, cls=None, object_hook=None, parse_float=None,
        parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)


-def loads(s, *, encoding=None, cls=None, object_hook=None, parse_float=None,
+def loads(s, *, cls=None, object_hook=None, parse_float=None,
        parse_int=None, parse_constant=None, object_pairs_hook=None, **kw):
    """Deserialize ``s`` (a ``str``, ``bytes`` or ``bytearray`` instance
    containing a JSON document) to a Python object.
@@ -330,7 +330,7 @@ def loads(s, *, encoding=None, cls=None, object_hook=None, parse_float=None,
    To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
    kwarg; otherwise ``JSONDecoder`` is used.

-    The ``encoding`` argument is ignored and deprecated.
+    The ``encoding`` argument is ignored and deprecated since Python 3.1.
    """
    if isinstance(s, str):
        if s.startswith('\ufeff'):
@@ -342,6 +342,15 @@ def loads(s, *, encoding=None, cls=None, object_hook=None, parse_float=None,
                            f'not {s.__class__.__name__}')
        s = s.decode(detect_encoding(s), 'surrogatepass')

+    if "encoding" in kw:
+        import warnings
+        warnings.warn(
+            "'encoding' is ignored and deprecated. It will be removed in Python 3.9",
+            DeprecationWarning,
+            stacklevel=2
+        )
+        del kw['encoding']
+
    if (cls is None and object_hook is None and
            parse_int is None and parse_float is None and
            parse_constant is None and object_pairs_hook is None and not kw):

diff --git a/Lib/test/test_json/test_decode.py b/Lib/test/test_json/test_decode.py
@@ -95,5 +95,9 @@ def test_negative_index(self):
        d = self.json.JSONDecoder()
        self.assertRaises(ValueError, d.raw_decode, 'a'*42, -50000)

+    def test_deprecated_encode(self):
+        with self.assertWarns(DeprecationWarning):
+            self.loads('{}', encoding='fake')
+
 class TestPyDecode(TestDecode, PyTest): pass
 class TestCDecode(TestDecode, CTest): pass
diff --git a/Misc/NEWS.d/next/Library/2019-04-09-14-46-28.bpo-33461.SYJM-E.rst b/Misc/NEWS.d/next/Library/2019-04-09-14-46-28.bpo-33461.SYJM-E.rst
@@ -0,0 +1,2 @@
+``json.loads`` now emits ``DeprecationWarning`` when ``encoding`` option is
+specified.  Patch by Matthias Bussonnier.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		``json.loads`` now emits ``DeprecationWarning`` when ``encoding`` option is
		specified. Patch by Matthias Bussonnier.