youknowone · Oct 15, 2026 · Oct 15, 2026
diff --git a/Lib/json/__init__.py b/Lib/json/__init__.py
@@ -95,7 +95,6 @@
     $ echo '{ 1.2:3.4}' | python -m json
     Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 """
-__version__ = '2.0.9'
 __all__ = [
     'dump', 'dumps', 'load', 'loads',
     'JSONDecoder', 'JSONDecodeError', 'JSONEncoder',
@@ -242,7 +241,7 @@ def dumps(obj, *, skipkeys=False, ensure_ascii=True, check_circular=True,
         **kw).encode(obj)
 
 
-_default_decoder = JSONDecoder(object_hook=None, object_pairs_hook=None)
+_default_decoder = JSONDecoder()
 
 
 def detect_encoding(b):
@@ -276,7 +275,8 @@ def detect_encoding(b):
 
 
 def load(fp, *, cls=None, object_hook=None, parse_float=None,
-        parse_int=None, parse_constant=None, object_pairs_hook=None, **kw):
+         parse_int=None, parse_constant=None, object_pairs_hook=None,
+         array_hook=None, **kw):
     """Deserialize ``fp`` (a ``.read()``-supporting file-like object containing
     a JSON document) to a Python object.
 
@@ -292,17 +292,27 @@ def load(fp, *, cls=None, object_hook=None, parse_float=None,
     ``object_hook`` is also defined, the ``object_pairs_hook`` takes
     priority.
 
+    ``array_hook`` is an optional function that will be called with the
+    result of any literal array decode (a ``list``).  The return value of
+    this function will be used instead of the ``list``.  This feature can
+    be used along ``object_pairs_hook`` to customize the resulting data
+    structure - for example, by setting that to ``frozendict`` and
+    ``array_hook`` to ``tuple``, one can get a deep immutable data structure
+    from any JSON data.
+
     To use a custom ``JSONDecoder`` subclass, specify it with the ``cls``
     kwarg; otherwise ``JSONDecoder`` is used.
     """
     return loads(fp.read(),
         cls=cls, object_hook=object_hook,
         parse_float=parse_float, parse_int=parse_int,
-        parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
+        parse_constant=parse_constant, object_pairs_hook=object_pairs_hook,
+        array_hook=array_hook, **kw)
 
 
 def loads(s, *, cls=None, object_hook=None, parse_float=None,
-        parse_int=None, parse_constant=None, object_pairs_hook=None, **kw):
+          parse_int=None, parse_constant=None, object_pairs_hook=None,
+          array_hook=None, **kw):
     """Deserialize ``s`` (a ``str``, ``bytes`` or ``bytearray`` instance
     containing a JSON document) to a Python object.
 
@@ -318,6 +328,14 @@ def loads(s, *, cls=None, object_hook=None, parse_float=None,
     ``object_hook`` is also defined, the ``object_pairs_hook`` takes
     priority.
 
+    ``array_hook`` is an optional function that will be called with the
+    result of any literal array decode (a ``list``).  The return value of
+    this function will be used instead of the ``list``.  This feature can
+    be used along ``object_pairs_hook`` to customize the resulting data
+    structure - for example, by setting that to ``frozendict`` and
+    ``array_hook`` to ``tuple``, one can get a deep immutable data structure
+    from any JSON data.
+
     ``parse_float``, if specified, will be called with the string
     of every JSON float to be decoded. By default this is equivalent to
     float(num_str). This can be used to use another datatype or parser
@@ -348,18 +366,30 @@ def loads(s, *, cls=None, object_hook=None, parse_float=None,
 
     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):
+            parse_constant is None and object_pairs_hook is None
+            and array_hook is None and not kw):
         return _default_decoder.decode(s)
     if cls is None:
         cls = JSONDecoder
     if object_hook is not None:
         kw['object_hook'] = object_hook
     if object_pairs_hook is not None:
         kw['object_pairs_hook'] = object_pairs_hook
+    if array_hook is not None:
+        kw['array_hook'] = array_hook
     if parse_float is not None:
         kw['parse_float'] = parse_float
     if parse_int is not None:
         kw['parse_int'] = parse_int
     if parse_constant is not None:
         kw['parse_constant'] = parse_constant
     return cls(**kw).decode(s)
+
+
+def __getattr__(name):
+    if name == "__version__":
+        from warnings import _deprecated
+
+        _deprecated("__version__", remove=(3, 20))
+        return "2.0.9"  # Do not change
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
@@ -27,20 +27,6 @@ class JSONDecodeError(ValueError):
     colno: The column corresponding to pos
 
     """
-    # RUSTPYTHON SPECIFIC
-    @classmethod
-    def _from_serde(cls, msg, doc, line, col):
-        pos = 0
-        # 0-indexed
-        line -= 1
-        col -= 1
-        while line > 0:
-            i = doc.index('\n', pos)
-            line -= 1
-            pos = i
-        pos += col
-        return cls(msg, doc, pos)
-
     # Note that this exception is used from _json
     def __init__(self, msg, doc, pos):
         lineno = doc.count('\n', 0, pos) + 1
@@ -57,11 +43,11 @@ def __reduce__(self):
         return self.__class__, (self.msg, self.doc, self.pos)
 
 
-_CONSTANTS = {
+_CONSTANTS = frozendict({
     '-Infinity': NegInf,
     'Infinity': PosInf,
     'NaN': NaN,
-}
+})
 
 
 HEXDIGITS = re.compile(r'[0-9A-Fa-f]{4}', FLAGS)
@@ -232,7 +218,7 @@ def JSONObject(s_and_end, strict, scan_once, object_hook, object_pairs_hook,
         pairs = object_hook(pairs)
     return pairs, end
 
-def JSONArray(s_and_end, scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
+def JSONArray(s_and_end, scan_once, array_hook, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
     s, end = s_and_end
     values = []
     nextchar = s[end:end + 1]
@@ -241,6 +227,8 @@ def JSONArray(s_and_end, scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
         nextchar = s[end:end + 1]
     # Look-ahead for trivial empty array
     if nextchar == ']':
+        if array_hook is not None:
+            values = array_hook(values)
         return values, end + 1
     _append = values.append
     while True:
@@ -270,6 +258,8 @@ def JSONArray(s_and_end, scan_once, _w=WHITESPACE.match, _ws=WHITESPACE_STR):
         if nextchar == ']':
             raise JSONDecodeError("Illegal trailing comma before end of array", s, comma_idx)
 
+    if array_hook is not None:
+        values = array_hook(values)
     return values, end
 
 
@@ -305,7 +295,7 @@ class JSONDecoder(object):
 
     def __init__(self, *, object_hook=None, parse_float=None,
             parse_int=None, parse_constant=None, strict=True,
-            object_pairs_hook=None):
+            object_pairs_hook=None, array_hook=None):
         """``object_hook``, if specified, will be called with the result
         of every JSON object decoded and its return value will be used in
         place of the given ``dict``.  This can be used to provide custom
@@ -318,6 +308,14 @@ def __init__(self, *, object_hook=None, parse_float=None,
         If ``object_hook`` is also defined, the ``object_pairs_hook`` takes
         priority.
 
+        ``array_hook`` is an optional function that will be called with the
+        result of any literal array decode (a ``list``). The return value of
+        this function will be used instead of the ``list``. This feature can
+        be used along ``object_pairs_hook`` to customize the resulting data
+        structure - for example, by setting that to ``frozendict`` and
+        ``array_hook`` to ``tuple``, one can get a deep immutable data
+        structute from any JSON data.
+
         ``parse_float``, if specified, will be called with the string
         of every JSON float to be decoded. By default this is equivalent to
         float(num_str). This can be used to use another datatype or parser
@@ -344,6 +342,7 @@ def __init__(self, *, object_hook=None, parse_float=None,
         self.parse_constant = parse_constant or _CONSTANTS.__getitem__
         self.strict = strict
         self.object_pairs_hook = object_pairs_hook
+        self.array_hook = array_hook
         self.parse_object = JSONObject
         self.parse_array = JSONArray
         self.parse_string = scanstring

diff --git a/Lib/json/encoder.py b/Lib/json/encoder.py
@@ -79,7 +79,7 @@ class JSONEncoder(object):
     +-------------------+---------------+
     | Python            | JSON          |
     +===================+===============+
-    | dict              | object        |
+    | dict, frozendict  | object        |
     +-------------------+---------------+
     | list, tuple       | array         |
     +-------------------+---------------+
@@ -264,17 +264,6 @@ def floatstr(o, allow_nan=self.allow_nan,
 
 def _make_iterencode(markers, _default, _encoder, _indent, _floatstr,
         _key_separator, _item_separator, _sort_keys, _skipkeys, _one_shot,
-        ## HACK: hand-optimized bytecode; turn globals into locals
-        ValueError=ValueError,
-        dict=dict,
-        float=float,
-        id=id,
-        int=int,
-        isinstance=isinstance,
-        list=list,
-        str=str,
-        tuple=tuple,
-        _intstr=int.__repr__,
     ):
 
     def _iterencode_list(lst, _current_indent_level):
@@ -311,15 +300,15 @@ def _iterencode_list(lst, _current_indent_level):
                     # Subclasses of int/float may override __repr__, but we still
                     # want to encode them as integers/floats in JSON. One example
                     # within the standard library is IntEnum.
-                    yield buf + _intstr(value)
+                    yield buf + int.__repr__(value)
                 elif isinstance(value, float):
                     # see comment above for int
                     yield buf + _floatstr(value)
                 else:
                     yield buf
                     if isinstance(value, (list, tuple)):
                         chunks = _iterencode_list(value, _current_indent_level)
-                    elif isinstance(value, dict):
+                    elif isinstance(value, (dict, frozendict)):
                         chunks = _iterencode_dict(value, _current_indent_level)
                     else:
                         chunks = _iterencode(value, _current_indent_level)
@@ -374,7 +363,7 @@ def _iterencode_dict(dct, _current_indent_level):
                 key = 'null'
             elif isinstance(key, int):
                 # see comment for int/float in _make_iterencode
-                key = _intstr(key)
+                key = int.__repr__(key)
             elif _skipkeys:
                 continue
             else:
@@ -399,14 +388,14 @@ def _iterencode_dict(dct, _current_indent_level):
                     yield 'false'
                 elif isinstance(value, int):
                     # see comment for int/float in _make_iterencode
-                    yield _intstr(value)
+                    yield int.__repr__(value)
                 elif isinstance(value, float):
                     # see comment for int/float in _make_iterencode
                     yield _floatstr(value)
                 else:
                     if isinstance(value, (list, tuple)):
                         chunks = _iterencode_list(value, _current_indent_level)
-                    elif isinstance(value, dict):
+                    elif isinstance(value, (dict, frozendict)):
                         chunks = _iterencode_dict(value, _current_indent_level)
                     else:
                         chunks = _iterencode(value, _current_indent_level)
@@ -434,13 +423,13 @@ def _iterencode(o, _current_indent_level):
             yield 'false'
         elif isinstance(o, int):
             # see comment for int/float in _make_iterencode
-            yield _intstr(o)
+            yield int.__repr__(o)
         elif isinstance(o, float):
             # see comment for int/float in _make_iterencode
             yield _floatstr(o)
         elif isinstance(o, (list, tuple)):
             yield from _iterencode_list(o, _current_indent_level)
-        elif isinstance(o, dict):
+        elif isinstance(o, (dict, frozendict)):
             yield from _iterencode_dict(o, _current_indent_level)
         else:
             if markers is not None:
@@ -458,4 +447,13 @@ def _iterencode(o, _current_indent_level):
                 raise
             if markers is not None:
                 del markers[markerid]
-    return _iterencode
+
+    def _iterencode_once(o, _current_indent_level):
+        nonlocal _iterencode, _iterencode_dict, _iterencode_list
+        try:
+            yield from _iterencode(o, _current_indent_level)
+        finally:
+            # Break reference cycles due to mutually recursive closures:
+            del _iterencode, _iterencode_dict, _iterencode_list
+
+    return _iterencode_once
diff --git a/Lib/json/scanner.py b/Lib/json/scanner.py
@@ -23,6 +23,7 @@ def py_make_scanner(context):
     parse_constant = context.parse_constant
     object_hook = context.object_hook
     object_pairs_hook = context.object_pairs_hook
+    array_hook = context.array_hook
     memo = context.memo
 
     def _scan_once(string, idx):
@@ -37,7 +38,7 @@ def _scan_once(string, idx):
             return parse_object((string, idx + 1), strict,
                 _scan_once, object_hook, object_pairs_hook, memo)
         elif nextchar == '[':
-            return parse_array((string, idx + 1), _scan_once)
+            return parse_array((string, idx + 1), _scan_once, array_hook)
         elif nextchar == 'n' and string[idx:idx + 4] == 'null':
             return None, idx + 4
         elif nextchar == 't' and string[idx:idx + 4] == 'true':

diff --git a/Lib/json/tool.py b/Lib/json/tool.py
@@ -22,13 +22,13 @@
     (?P<null>null)
 ''', re.VERBOSE)
 
-_group_to_theme_color = {
+_group_to_theme_color = frozendict({
     "key": "definition",
     "string": "string",
     "number": "number",
     "boolean": "keyword",
     "null": "keyword",
-}
+})
 
 
 def _colorize_json(json_str, theme):
@@ -44,20 +44,21 @@ def _replace_match_callback(match):
 def main():
     description = ('A simple command line interface for json module '
                    'to validate and pretty-print JSON objects.')
-    parser = argparse.ArgumentParser(description=description, color=True)
+    parser = argparse.ArgumentParser(description=description)
     parser.add_argument('infile', nargs='?',
-                        help='a JSON file to be validated or pretty-printed',
+                        help='a JSON file to be validated or pretty-printed; '
+                             'defaults to `stdin`',
                         default='-')
     parser.add_argument('outfile', nargs='?',
-                        help='write the output of infile to outfile',
+                        help='write the output of `infile` to `outfile`',
                         default=None)
     parser.add_argument('--sort-keys', action='store_true', default=False,
                         help='sort the output of dictionaries alphabetically by key')
     parser.add_argument('--no-ensure-ascii', dest='ensure_ascii', action='store_false',
                         help='disable escaping of non-ASCII characters')
     parser.add_argument('--json-lines', action='store_true', default=False,
                         help='parse input using the JSON Lines format. '
-                        'Use with --no-indent or --compact to produce valid JSON Lines output.')
+                        'Use with `--no-indent` or `--compact` to produce valid JSON Lines output.')
     group = parser.add_mutually_exclusive_group()
     group.add_argument('--indent', default=4, type=int,
                        help='separate items with newlines and use this number '