MDEV-13707 Server in ORACLE mode crashes on ALTER with wrong DEFAULT clause

mysql-test/r/default.result

@@ -3381,4 +3381,11 @@ create table t1 (col1 int default(-(default(col1))));
 ERROR 01000: Expression for field `col1` is refering to uninitialized field `col1`
 create table t1 (col int default (yearweek((exp(710)))));
 ERROR 22003: DOUBLE value is out of range in 'exp(710)'
+#
+# MDEV-13707 Server in ORACLE mode crashes on ALTER with wrong DEFAULT clause
+#
+CREATE OR REPLACE TABLE t1(i int);
+ALTER TABLE t1 ADD b CHAR(255) DEFAULT `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`;
+ERROR 42S22: Unknown column 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' in 'DEFAULT'
+DROP TABLE t1;
 # end of 10.2 test

mysql-test/t/default.test

@@ -2095,4 +2095,14 @@ create table t1 (col1 int default(-(default(col1))));
 --error ER_DATA_OUT_OF_RANGE
 create table t1 (col int default (yearweek((exp(710)))));
 
+--echo #
+--echo # MDEV-13707 Server in ORACLE mode crashes on ALTER with wrong DEFAULT clause
+--echo #
+
+CREATE OR REPLACE TABLE t1(i int);
+--error ER_BAD_FIELD_ERROR
+ALTER TABLE t1 ADD b CHAR(255) DEFAULT `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`;
+DROP TABLE t1;
+
+
 --echo # end of 10.2 test

sql/item.cc

@@ -1446,9 +1446,9 @@ static inline
 void mark_unsupported_func(const char *where, const char *processor_name)
 {
   char buff[64];
-  sprintf(buff, "%s::%s", where ? where: "", processor_name);
+  my_snprintf(buff, sizeof(buff), "%s::%s", where ? where: "", processor_name);
   DBUG_ENTER(buff);
-  sprintf(buff, "%s returns TRUE: unsupported function", processor_name);
+  my_snprintf(buff, sizeof(buff), "%s returns TRUE: unsupported function", processor_name);
   DBUG_PRINT("info", ("%s", buff));
   DBUG_VOID_RETURN;
 }