From a8abe097c1165db25b429ca02a65c4f8acbc062b Mon Sep 17 00:00:00 2001 From: Matthias Bussonnier Date: Tue, 9 Apr 2019 00:17:25 -0700 Subject: [PATCH] bpo-33461: emit DeprecationWarning when json.loads(encoding=...) is used (GH-6762) --- Doc/library/json.rst | 7 +++++-- Lib/json/__init__.py | 13 +++++++++++-- Lib/test/test_json/test_decode.py | 4 ++++ .../2019-04-09-14-46-28.bpo-33461.SYJM-E.rst | 2 ++ 4 files changed, 22 insertions(+), 4 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2019-04-09-14-46-28.bpo-33461.SYJM-E.rst diff --git a/Doc/library/json.rst b/Doc/library/json.rst index 589e86ca81..b476c37237 100644 --- 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 `. 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 index 3bb4490e81..1ba8b48bd7 100644 --- 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 index fdb9e62124..895c95b54c 100644 --- a/Lib/test/test_json/test_decode.py +++ b/Lib/test/test_json/test_decode.py @@ -95,5 +95,9 @@ class TestDecode: 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 new file mode 100644 index 0000000000..12b3bceaf8 --- /dev/null +++ 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. -- 2.50.1