Backport PR #45489: Bug tojson memleak (#45545)

Co-authored-by: vernetya <[email protected]>

Author: meeseeksmachine

doc/source/whatsnew/v1.4.0.rst

@@ -966,6 +966,7 @@ I/O
 - Bug in :func:`read_json` raising ``ValueError`` when attempting to parse json strings containing "://" (:issue:`36271`)
 - Bug in :func:`read_csv` when ``engine="c"`` and ``encoding_errors=None`` which caused a segfault (:issue:`45180`)
 - Bug in :func:`read_csv` an invalid value of ``usecols`` leading to an unclosed file handle (:issue:`45384`)
+- Bug in :meth:`DataFrame.to_json` fix memory leak (:issue:`43877`)
 
 Period
 ^^^^^^

pandas/_libs/src/ujson/python/objToJSON.c

@@ -228,6 +228,7 @@ static PyObject *get_values(PyObject *obj) {
             PyErr_Clear();
         } else if (PyObject_HasAttrString(values, "__array__")) {
             // We may have gotten a Categorical or Sparse array so call np.array
+            Py_DECREF(values);
             values = PyObject_CallMethod(values, "__array__", NULL);
         } else if (!PyArray_CheckExact(values)) {
             // Didn't get a numpy array, so keep trying