Backport of bug#38719 from 6.0 to 5.1

handler::get_dup_key used the called handler for the
info call, but used table->file handler for errkey.
Fixed by using table->file->info instead.

mysql-test/r/partition_error.result:
  Bug#38719: Partitioning returns a different error code for
  a duplicate key error
  
  Added test for verification
mysql-test/t/partition_error.test:
  Bug#38719: Partitioning returns a different error code for
  a duplicate key error
  
  Added test for verification

mysql-test/r/partition_error.result

 drop table if exists t1;
+CREATE TABLE t1 (a INTEGER NOT NULL, PRIMARY KEY (a));
+INSERT INTO t1 VALUES (1),(1);
+ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
+DROP TABLE t1;
+CREATE TABLE t1 (a INTEGER NOT NULL, PRIMARY KEY (a))
+PARTITION BY KEY (a) PARTITIONS 2;
+INSERT INTO t1 VALUES (1),(1);
+ERROR 23000: Duplicate entry '1' for key 'PRIMARY'
+DROP TABLE t1;
 CREATE TABLE t1 (a INT)
 PARTITION BY HASH (a)
 ( PARTITION p0 ENGINE=MyISAM,

mysql-test/t/partition_error.test

 #
-# Simple test for the erroneos create statements using the 
+# Simple test for the erroneos statements using the 
 # partition storage engine
 #
 -- source include/have_partition.inc
@@ -7,6 +7,19 @@
 --disable_warnings
 drop table if exists t1;
 --enable_warnings
+ 
+#
+# Bug#38719: Partitioning returns a different error code for a
+# duplicate key error
+CREATE TABLE t1 (a INTEGER NOT NULL, PRIMARY KEY (a));
+-- error ER_DUP_ENTRY
+INSERT INTO t1 VALUES (1),(1);
+DROP TABLE t1;
+CREATE TABLE t1 (a INTEGER NOT NULL, PRIMARY KEY (a))
+PARTITION BY KEY (a) PARTITIONS 2;
+-- error ER_DUP_ENTRY
+INSERT INTO t1 VALUES (1),(1);
+DROP TABLE t1;
 
 #
 # Bug#31931: Mix of handlers error message

sql/handler.cc

@@ -2932,7 +2932,7 @@ uint handler::get_dup_key(int error)
   if (error == HA_ERR_FOUND_DUPP_KEY || error == HA_ERR_FOREIGN_DUPLICATE_KEY ||
       error == HA_ERR_FOUND_DUPP_UNIQUE || error == HA_ERR_NULL_IN_SPATIAL ||
       error == HA_ERR_DROP_INDEX_FK)
-    info(HA_STATUS_ERRKEY | HA_STATUS_NO_LOCK);
+    table->file->info(HA_STATUS_ERRKEY | HA_STATUS_NO_LOCK);
   DBUG_RETURN(table->file->errkey);
 }