Fix for bug#57283: inet_ntoa() crashes

Problem: some call of INET_NTOA() function may lead 
to a crash due to missing its character set initialization.

Fix: explicitly set the character set.

mysql-test/r/func_misc.result

@@ -351,4 +351,10 @@ GREATEST(a, (SELECT b FROM t1 LIMIT 1))
 3
 1
 DROP TABLE t1;
+SELECT INET_NTOA(0);
+INET_NTOA(0)
+0.0.0.0
+SELECT '1' IN ('1', INET_NTOA(0));
+'1' IN ('1', INET_NTOA(0))
+1
 End of tests

mysql-test/t/func_misc.test

@@ -479,4 +479,12 @@ SELECT DISTINCT GREATEST(a, (SELECT b FROM t1 LIMIT 1)) FROM t1 UNION SELECT 1;
 
 DROP TABLE t1;
 
+
+#
+# Bug #57283: inet_ntoa() crashes
+#
+SELECT INET_NTOA(0);
+SELECT '1' IN ('1', INET_NTOA(0));
+
+
 --echo End of tests

sql/item_strfunc.cc

@@ -3135,6 +3135,7 @@ String* Item_func_inet_ntoa::val_str(String* str)
   if ((null_value= (args[0]->null_value || n > (ulonglong) LL(4294967295))))
     return 0;					// Null value
 
+  str->set_charset(collation.collation);
   str->length(0);
   int4store(buf,n);