bk commit into 5.0 tree (evgen:1.2162) BUG#15962

[eugene]

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ChangeSet
  1.2162 06/06/07 01:10:23 evgen@stripped +3 -0
  Fixed bug#15962: CONCAT() in UNION may lead to a data trucation.
  
  To calculate its max_length the CONCAT() function is simply sums max_lengths
  of its arguments but when the collation of an argument differs from the 
  collation of the CONCAT() max_length will be wrong. This may lead to a data
  truncation when a tmp table is used, in UNIONS for example.
  
  The Item_func_concat::fix_length_and_dec() function now recalculates the 
  max_length of an argument when the mbmaxlen of the argument differs from the
  mbmaxlen of the CONCAT().

  sql/item_strfunc.cc
    1.267 06/06/07 01:07:31 evgen@stripped +8 -1
    Fixed bug#15962: CONCAT() in UNION may lead to a data trucation.
    The Item_func_concat::fix_length_and_dec() function now recalculates the 
    max_length of an argument when the mbmaxlen of the argument differs from the
    mbmaxlen of the CONCAT().

  mysql-test/r/func_concat.result
    1.9 06/06/07 01:06:30 evgen@stripped +7 -0
    Added test case for bug#15962:CONCAT() in UNION may lead to a data trucation.

  mysql-test/t/func_concat.test
    1.11 06/06/07 01:05:49 evgen@stripped +8 -0
    Added test case for bug#15962:CONCAT() in UNION may lead to a data trucation.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	evgen
# Host:	moonbone.local
# Root:	/work/15962-bug-5.0-opt-mysql

--- 1.266/sql/item_strfunc.cc	2006-05-12 11:15:11 +04:00
+++ 1.267/sql/item_strfunc.cc	2006-06-07 01:07:31 +04:00
@@ -389,7 +389,14 @@
     return;
 
   for (uint i=0 ; i < arg_count ; i++)
-    max_result_length+= args[i]->max_length;
+  {
+    if (args[i]->collation.collation->mbmaxlen != collation.collation->mbmaxlen)
+      max_result_length+= (args[i]->max_length /
+                           args[i]->collation.collation->mbmaxlen) *
+                           collation.collation->mbmaxlen;
+    else
+      max_result_length+= args[i]->max_length;
+  }
 
   if (max_result_length >= MAX_BLOB_WIDTH)
   {

--- 1.8/mysql-test/r/func_concat.result	2005-01-04 14:46:42 +03:00
+++ 1.9/mysql-test/r/func_concat.result	2006-06-07 01:06:30 +04:00
@@ -68,3 +68,10 @@
 a
 a
 a0.0000
+create table t1(f1 varchar(6)) charset=utf8;
+insert into t1 values ("123456");
+select concat(f1, 2) a from t1 union select 'x' a from t1;
+a
+1234562
+x
+drop table t1;

--- 1.10/mysql-test/t/func_concat.test	2005-09-15 23:17:37 +04:00
+++ 1.11/mysql-test/t/func_concat.test	2006-06-07 01:05:49 +04:00
@@ -53,3 +53,11 @@
 select 'a' union select concat('a', -0.0000);
 
 # End of 4.1 tests
+
+#
+# Bug#15962: CONCAT() in UNION may lead to a data trucation.
+#
+create table t1(f1 varchar(6)) charset=utf8;
+insert into t1 values ("123456");
+select concat(f1, 2) a from t1 union select 'x' a from t1;
+drop table t1;