MDEV-9842 LOAD DATA INFILE does not work well with a TEXT column when using sjis

mysql-test/r/ctype_sjis.result

@@ -18730,3 +18730,21 @@ DROP TABLE t1;
 #
 # End of 10.0 tests
 #
+#
+# Start of 10.2 tests
+#
+#
+# MDEV-9842 LOAD DATA INFILE does not work well with a TEXT column when using sjis
+#
+CREATE TABLE t1 (a TEXT CHARACTER SET sjis);
+LOAD DATA INFILE '../../std_data/loaddata/mdev9842.txt' INTO TABLE t1 CHARACTER SET sjis;
+SELECT HEX(a) FROM t1;
+HEX(a)
+78835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C835C
+SELECT a=CONCAT('x', REPEAT(_sjis 0x835C, 200)) FROM t1;
+a=CONCAT('x', REPEAT(_sjis 0x835C, 200))
+1
+DROP TABLE t1;
+#
+# End of 10.2 tests
+#

mysql-test/std_data/loaddata/mdev9842.txt

+x\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

mysql-test/t/ctype_sjis.test

@@ -231,3 +231,21 @@ SET NAMES sjis;
 --echo #
 --echo # End of 10.0 tests
 --echo #
+
+--echo #
+--echo # Start of 10.2 tests
+--echo #
+
+--echo #
+--echo # MDEV-9842 LOAD DATA INFILE does not work well with a TEXT column when using sjis
+--echo #
+CREATE TABLE t1 (a TEXT CHARACTER SET sjis);
+LOAD DATA INFILE '../../std_data/loaddata/mdev9842.txt' INTO TABLE t1 CHARACTER SET sjis;
+SELECT HEX(a) FROM t1;
+SELECT a=CONCAT('x', REPEAT(_sjis 0x835C, 200)) FROM t1;
+DROP TABLE t1;
+
+
+--echo #
+--echo # End of 10.2 tests
+--echo #

sql/sql_load.cc

@@ -1492,7 +1492,8 @@ int READ_INFO::read_field()
 
   for (;;)
   {
-    while ( to < end_of_buff)
+    // Make sure we have enough space for the longest multi-byte character.
+    while ( to + read_charset->mbmaxlen <= end_of_buff)
     {
       chr = GET;
       if (chr == my_b_EOF)