Jan 12, 2026 · Jan 12, 2026
diff --git a/Lib/test/test_json/test_speedups.py b/Lib/test/test_json/test_speedups.py
    def test_unsortable_keys(self):
        with self.assertRaises(TypeError):
            self.json.encoder.JSONEncoder(sort_keys=True).encode({'a': 1, 1: 'a'})

    def test_current_indent_level(self):
        enc = self.json.encoder.c_make_encoder(
            markers=None,
            default=str,
            encoder=self.json.encoder.c_encode_basestring,
            indent='\t',
            key_separator=': ',
            item_separator=', ',
            sort_keys=False,
            skipkeys=False,
            allow_nan=False)
        expected = (
            '[\n'
            '\t"spam", \n'
            '\t{\n'
            '\t\t"ham": "eggs"\n'
            '\t}\n'
            ']')
        self.assertEqual(enc(['spam', {'ham': 'eggs'}], 0)[0], expected)
        self.assertEqual(enc(['spam', {'ham': 'eggs'}], -3)[0], expected)
        expected2 = (
            '[\n'
            '\t\t\t\t"spam", \n'
            '\t\t\t\t{\n'
            '\t\t\t\t\t"ham": "eggs"\n'
            '\t\t\t\t}\n'
            '\t\t\t]')
        self.assertEqual(enc(['spam', {'ham': 'eggs'}], 3)[0], expected2)
        self.assertRaises(TypeError, enc, ['spam', {'ham': 'eggs'}], 3.0)
        self.assertRaises(TypeError, enc, ['spam', {'ham': 'eggs'}])
diff --git a/Misc/NEWS.d/next/Library/2026-01-09-17-50-26.gh-issue-143196.WxKxzU.rst b/Misc/NEWS.d/next/Library/2026-01-09-17-50-26.gh-issue-143196.WxKxzU.rst
 Fix crash when the internal encoder object returned by undocumented function
 :func:`!json.encoder.c_make_encoder` was called with non-zero second
 (*_current_indent_level*) argument.
diff --git a/Modules/_json.c b/Modules/_json.c
            return NULL;
        }
    }
    indent_level = 0;
    if (encoder_listencode_obj(self, writer, obj, indent_level, indent_cache)) {
        PyUnicodeWriter_Discard(writer);
        Py_XDECREF(indent_cache);
Original file line number	Diff line number	Diff line change
Expand Up		@@ -80,3 +80,34 @@ def test(name):
		def test_unsortable_keys(self):
		with self.assertRaises(TypeError):
		self.json.encoder.JSONEncoder(sort_keys=True).encode({'a': 1, 1: 'a'})

		def test_current_indent_level(self):
		enc = self.json.encoder.c_make_encoder(
		markers=None,
		default=str,
		encoder=self.json.encoder.c_encode_basestring,
		indent='\t',
		key_separator=': ',
		item_separator=', ',
		sort_keys=False,
		skipkeys=False,
		allow_nan=False)
		expected = (
		'[\n'
		'\t"spam", \n'
		'\t{\n'
		'\t\t"ham": "eggs"\n'
		'\t}\n'
		']')
		self.assertEqual(enc(['spam', {'ham': 'eggs'}], 0)[0], expected)
		self.assertEqual(enc(['spam', {'ham': 'eggs'}], -3)[0], expected)
		expected2 = (
		'[\n'
		'\t\t\t\t"spam", \n'
		'\t\t\t\t{\n'
		'\t\t\t\t\t"ham": "eggs"\n'
		'\t\t\t\t}\n'
		'\t\t\t]')
		self.assertEqual(enc(['spam', {'ham': 'eggs'}], 3)[0], expected2)
		self.assertRaises(TypeError, enc, ['spam', {'ham': 'eggs'}], 3.0)
		self.assertRaises(TypeError, enc, ['spam', {'ham': 'eggs'}])
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		Fix crash when the internal encoder object returned by undocumented function
		:func:`!json.encoder.c_make_encoder` was called with non-zero second
		(_current_indent_level) argument.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -1383,6 +1383,7 @@ encoder_call(PyObject op, PyObject args, PyObject *kwds)
		return NULL;
		}
		}
		indent_level = 0;
		if (encoder_listencode_obj(self, writer, obj, indent_level, indent_cache)) {
		PyUnicodeWriter_Discard(writer);
		Py_XDECREF(indent_cache);
Expand Down