Bug#28925 GROUP_CONCAT inserts wrong separators for a ucs2 column

Problem: separator was not converted to the result character set,
so the result was a mixture of two different character sets,
which was especially bad for UCS2.
Fix: convert separator to the result character set.


mysql-test/r/ctype_ucs.result:
  Adding test case
mysql-test/r/ctype_ucs2_def.result:
  Adding test case
mysql-test/t/ctype_ucs.test:
  Adding test case
mysql-test/t/ctype_ucs2_def.test:
  Adding test case
sql/item_sum.cc:
  Adding conversion of separator to the result character set
sql/sql_yacc.yy:
  Fixing GROUPC_CONCAT problems when "mysqld --default-character-set=ucs2".

1 files changed, 21 insertions, 0 deletions

diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index ea2a14ffb63..be1946b4677 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -3209,6 +3209,27 @@ Item_func_group_concat::fix_fields(THD *thd, Item **ref)
   null_value= 1;
   max_length= thd->variables.group_concat_max_len;
 
+  uint32 offset;
+  if (separator->needs_conversion(separator->length(), separator->charset(),
+                                  collation.collation, &offset))
+  {
+    uint32 buflen= collation.collation->mbmaxlen * separator->length();
+    uint errors, conv_length;
+    char *buf;
+    String *new_separator;
+
+    if (!(buf= thd->stmt_arena->alloc(buflen)) ||
+        !(new_separator= new(thd->stmt_arena->mem_root)
+                           String(buf, buflen, collation.collation)))
+      return TRUE;
+    
+    conv_length= copy_and_convert(buf, buflen, collation.collation,
+                                  separator->ptr(), separator->length(),
+                                  separator->charset(), &errors);
+    new_separator->length(conv_length);
+    separator= new_separator;
+  }
+
   if (check_sum_func(thd, ref))
     return TRUE;