Use try/except block to properly catch and handle the exception

Now no more warnings

Author: roberthdevries

pandas/_libs/hashtable_class_helper.pxi.in

@@ -12,9 +12,6 @@ WARNING: DO NOT edit .pxi FILE directly, .pxi is generated from .pxi.in
 from pandas._libs.tslibs.util cimport get_c_string
 from pandas._libs.missing cimport C_NA
 
-cdef extern from "Python.h":
-    void PyErr_Clear()
-
 {{py:
 
 # name, dtype, c_type
@@ -794,7 +791,6 @@ cdef class StringHashTable(HashTable):
                 # if ignore_na is False, we also stringify NaN/None/etc.
                 v = get_c_string(<str>val)
                 if v == NULL:
-                    PyErr_Clear()
                     v = get_c_string(<str>repr(val))
                 vecs[i] = v
 

pandas/_libs/tslibs/util.pxd

@@ -238,11 +238,10 @@ cdef inline const char* get_c_string_buf_and_size(str py_string,
     -------
     buf : const char*
     """
-    cdef:
-        const char *buf
-
-    buf = PyUnicode_AsUTF8AndSize(py_string, length)
-    return buf
+    try:
+        return PyUnicode_AsUTF8AndSize(py_string, length)
+    except UnicodeEncodeError:
+        return NULL
 
 
 cdef inline const char* get_c_string(str py_string):