fix string literal escaping in views

process multibyte characters correctly, don't escape half of the character

mysql-test/include/ctype_E05C.inc

@@ -76,6 +76,15 @@ INSERT INTO t1 VALUES (_BINARY'\\''
 SELECT a, HEX(a) FROM t1;
 DROP TABLE t1;
 
+#
+# test how strings are written into view's frm
+#
+disable_view_protocol;
+create view v1 as select hex('à\'), hex('à\t');
+select * from v1;
+drop view v1;
+enable_view_protocol;
+
 # Checking that with character_set_client=binary 0x5C in 0xE05C
 # is treated as escape rather than the second byte of a multi-byte character,
 # even if character_set_connection is big5/cp932/gbk/sjis.
@@ -109,5 +118,5 @@ SELECT HEX(a) FROM t1;
 DROP TABLE t1;
 --enable_view_protocol
 
---echo # Start of ctype_E05C.inc
+--echo # End of ctype_E05C.inc
 

mysql-test/main/ctype_big5.result

@@ -537,15 +537,15 @@ create table t1 (a blob);
 insert into t1 values (0xEE00);
 select * into outfile 'test/t1.txt' from t1;
 delete from t1;
-select hex(load_file('MYSQLD_DATADIR/test/t1.txt'));;
-hex(load_file('MYSQLD_DATADIR/test/t1.txt'))
+select hex(load_file('MYSQLD_DATADIR/test/t1.txt')) as lf;
+lf
 5CEE5C300A
 load data infile 't1.txt' into table t1;
 select hex(a) from t1;
 hex(a)
 EE00
 drop table t1;
-End of 5.0 tests
+# End of 5.0 tests
 #
 # Start of 5.5 tests
 #
@@ -4705,6 +4705,11 @@ a	HEX(a)
 \'�\	5C27E05C
 �\'\	E05C275C
 DROP TABLE t1;
+create view v1 as select hex('�\'), hex('�\t');
+select * from v1;
+hex('�\')	hex('�\t')
+E05C	E05C74
+drop view v1;
 SET character_set_client=binary, character_set_results=binary;
 SELECT @@character_set_client, @@character_set_connection, @@character_set_results;
 @@character_set_client	@@character_set_connection	@@character_set_results
@@ -4744,7 +4749,7 @@ HEX(a)
 E05C5B
 E05B
 DROP TABLE t1;
-# Start of ctype_E05C.inc
+# End of ctype_E05C.inc
 SET NAMES big5;
 CREATE TABLE t1 (a ENUM('�@') CHARACTER SET big5);
 SHOW CREATE TABLE t1;

mysql-test/main/ctype_big5.test

@@ -79,18 +79,15 @@ create table t1 (a blob);
 insert into t1 values (0xEE00);
 select * into outfile 'test/t1.txt' from t1;
 delete from t1;
-#enable after fix MDEV-27871
---disable_view_protocol
 let $MYSQLD_DATADIR= `select @@datadir`;
 --replace_result $MYSQLD_DATADIR MYSQLD_DATADIR
---eval select hex(load_file('$MYSQLD_DATADIR/test/t1.txt'));
+--eval select hex(load_file('$MYSQLD_DATADIR/test/t1.txt')) as lf
 load data infile 't1.txt' into table t1;
 select hex(a) from t1;
 --remove_file $MYSQLD_DATADIR/test/t1.txt
 drop table t1;
-#enable_view_protocol
 #
---echo End of 5.0 tests
+--echo # End of 5.0 tests
 
 
 --echo #

mysql-test/main/ctype_cp932_binlog_stm.result

@@ -20413,6 +20413,11 @@ a	HEX(a)
 \'�\	5C27E05C
 �\'\	E05C275C
 DROP TABLE t1;
+create view v1 as select hex('�\'), hex('�\t');
+select * from v1;
+hex('�\')	hex('�\t')
+E05C	E05C74
+drop view v1;
 SET character_set_client=binary, character_set_results=binary;
 SELECT @@character_set_client, @@character_set_connection, @@character_set_results;
 @@character_set_client	@@character_set_connection	@@character_set_results
@@ -20452,7 +20457,7 @@ HEX(a)
 E05C5B
 E05B
 DROP TABLE t1;
-# Start of ctype_E05C.inc
+# End of ctype_E05C.inc
 #
 # End of 10.0 tests
 #

mysql-test/main/ctype_gbk.result

@@ -5053,6 +5053,11 @@ a	HEX(a)
 \'�\	5C27E05C
 �\'\	E05C275C
 DROP TABLE t1;
+create view v1 as select hex('�\'), hex('�\t');
+select * from v1;
+hex('�\')	hex('�\t')
+E05C	E05C74
+drop view v1;
 SET character_set_client=binary, character_set_results=binary;
 SELECT @@character_set_client, @@character_set_connection, @@character_set_results;
 @@character_set_client	@@character_set_connection	@@character_set_results
@@ -5092,7 +5097,7 @@ HEX(a)
 E05C5B
 E05B
 DROP TABLE t1;
-# Start of ctype_E05C.inc
+# End of ctype_E05C.inc
 SET NAMES utf8, character_set_connection=gbk;
 #
 # MDEV-13118 Wrong results with LOWER and UPPER and subquery

mysql-test/main/ctype_sjis.result

@@ -18677,6 +18677,11 @@ a	HEX(a)
 \'�\	5C27E05C
 �\'\	E05C275C
 DROP TABLE t1;
+create view v1 as select hex('�\'), hex('�\t');
+select * from v1;
+hex('�\')	hex('�\t')
+E05C	E05C74
+drop view v1;
 SET character_set_client=binary, character_set_results=binary;
 SELECT @@character_set_client, @@character_set_connection, @@character_set_results;
 @@character_set_client	@@character_set_connection	@@character_set_results
@@ -18716,7 +18721,7 @@ HEX(a)
 E05C5B
 E05B
 DROP TABLE t1;
-# Start of ctype_E05C.inc
+# End of ctype_E05C.inc
 #
 # End of 10.0 tests
 #

sql/sql_string.cc

@@ -1115,22 +1115,28 @@ String_copier::well_formed_copy(CHARSET_INFO *to_cs,
   characters with backslashes as necessary.
   Does not add the enclosing quotes, this is left up to caller.
 */
-#define APPEND(X)   if (append(X)) return 1; else break
+#define APPEND(...)   if (append(__VA_ARGS__)) return 1;
 bool String::append_for_single_quote(const char *st, size_t len)
 {
   const char *end= st+len;
+  int chlen;
   for (; st < end; st++)
   {
-    uchar c= *st;
-    switch (c)
+    switch (*st)
     {
-    case '\\':   APPEND(STRING_WITH_LEN("\\\\"));
-    case '\0':   APPEND(STRING_WITH_LEN("\\0"));
-    case '\'':   APPEND(STRING_WITH_LEN("\\'"));
-    case '\n':   APPEND(STRING_WITH_LEN("\\n"));
-    case '\r':   APPEND(STRING_WITH_LEN("\\r"));
-    case '\032': APPEND(STRING_WITH_LEN("\\Z"));
-    default:     APPEND(c);
+    case '\\':   APPEND(STRING_WITH_LEN("\\\\")); break;
+    case '\0':   APPEND(STRING_WITH_LEN("\\0")); break;
+    case '\'':   APPEND(STRING_WITH_LEN("\\'")); break;
+    case '\n':   APPEND(STRING_WITH_LEN("\\n")); break;
+    case '\r':   APPEND(STRING_WITH_LEN("\\r")); break;
+    case '\032': APPEND(STRING_WITH_LEN("\\Z")); break;
+    default:     if ((chlen= my_charlen(charset(), st, end)) > 0)
+                 {
+                   APPEND(st, chlen);
+                   st+= chlen-1;
+                 }
+                 else
+                   APPEND(*st);
     }
   }
   return 0;