BUG#39753: Replication failure on MIXED + bit + myisam + no PK

When using mixed mode the record values stored inside the storage
engine differed from the ones computed from the row event. This
happened because the prepare_record function was calling
empty_record macro causing some don't care bits to be left set.
                          
Replacing the empty_record plus explicitly setting defaults with 
restore_record to restore the record default values fixes this.

mysql-test/suite/rpl/r/rpl_mixed_bit_pk.result

@@ -0,0 +1,32 @@
+stop slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+reset master;
+reset slave;
+drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t9;
+start slave;
+DROP TABLE IF EXISTS t1,t2,t3,t4,t5,t6,t7,t8;
+CREATE TABLE t1 (`bit_key` bit, `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t2 (`bit_key` bit(4), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t3 (`bit_key` bit(7), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t4 (`bit_key` bit(8), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t5 (`bit_key` bit(9), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t6 (`bit_key` bit(14), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t7 (`bit_key` bit(15), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t8 (`bit_key` bit(16), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+INSERT INTO `t1` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t1` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t2` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t2` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t3` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t3` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t4` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t4` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t5` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t5` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t6` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t6` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t7` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t7` WHERE `bit` < 2 LIMIT 4;
+INSERT INTO `t8` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t8` WHERE `bit` < 2 LIMIT 4;
+DROP TABLE t1, t2, t3, t4, t5, t6, t7, t8;

mysql-test/suite/rpl/t/rpl_mixed_bit_pk.test

@@ -0,0 +1,78 @@
+#
+# BUG
+# ---
+#  BUG#39753: Replication failure on MIXED + bit + myisam + no PK
+#
+# Description
+# -----------
+#  Simple statements against a bit column cause failure in mixed-mode
+#  replication.
+#
+#  Implementation is as follows:
+#     i) A table with two bit fields is created. One of them is a key.
+#    ii) A record is inserted without specifying the key value.
+#   iii) The record is deleted using a where clause that matches it.
+#    iv) repeat i-iii) for bit key that has different size, generating
+#        different extra bits values 
+#     v) The slave is synchronized with master 
+#    vi) The table is dropped on master and the slave is re-synchronized
+#        with master.
+#
+#  Step v) made the bug evident before the patch, as the slave would 
+#  fail to find the correspondent row in its database (although it did
+#  the insert in step ii) ).
+#
+# Obs
+# --- 
+#  This test is based on the "how to repeat" section from the bug report.
+#
+#
+
+--source include/master-slave.inc
+
+--disable_warnings
+# setup
+
+DROP TABLE IF EXISTS t1,t2,t3,t4,t5,t6,t7,t8;
+CREATE TABLE t1 (`bit_key` bit, `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t2 (`bit_key` bit(4), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t3 (`bit_key` bit(7), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t4 (`bit_key` bit(8), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t5 (`bit_key` bit(9), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t6 (`bit_key` bit(14), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t7 (`bit_key` bit(15), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+CREATE TABLE t8 (`bit_key` bit(16), `bit` bit, key (`bit_key` )) ENGINE=MyISAM;
+
+# insert and delete
+INSERT INTO `t1` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t1` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t2` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t2` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t3` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t3` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t4` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t4` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t5` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t5` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t6` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t6` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t7` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t7` WHERE `bit` < 2 LIMIT 4;
+
+INSERT INTO `t8` ( `bit` ) VALUES ( 0 );
+DELETE FROM `t8` WHERE `bit` < 2 LIMIT 4;
+
+
+--enable_warnings
+sync_slave_with_master;
+
+# clean up 
+connection master;
+DROP TABLE t1, t2, t3, t4, t5, t6, t7, t8;
+sync_slave_with_master;

sql/rpl_record.cc

@@ -297,21 +297,16 @@ unpack_row(Relay_log_info const *rli,
 /**
   Fills @c table->record[0] with default values.
 
-  First @c empty_record() is called and then, additionally, fields are
+  First @c restore_record() is called to restore the default values for
-  initialized explicitly with a call to @c set_default().
+  record concerning the given table. Then, if @c check is true, 
-
+  a check is performed to see if fields are have default value or can 
-  For optimization reasons, the explicit initialization can be skipped for
+  be NULL. Otherwise error is reported.
-  first @c skip fields. This is useful if later we are going to fill these 
-  fields from other source (e.g. from a Rows replication event).
-
-  If @c check is true, fields are explicitly initialized only if they have
-  default value or can be NULL. Otherwise error is reported.
  
   @param table  Table whose record[0] buffer is prepared. 
-  @param skip   Number of columns for which default value initialization 
+  @param skip   Number of columns for which default/nullable check 
                 should be skipped.
-  @param check  Indicates if errors should be checked when setting default
+  @param check  Indicates if errors should be raised when checking 
-                values.
+                default/nullable field properties.
                 
   @returns 0 on success or a handler level error code
  */ 
@@ -321,25 +316,28 @@ int prepare_record(TABLE *const table,
   DBUG_ENTER("prepare_record");
 
   int error= 0;
-  empty_record(table);
+  restore_record(table, s->default_values);
 
-  if (skip >= table->s->fields)  // nothing to do
+  /*
+     This skip should be revisited in 6.0, because in 6.0 RBR one 
+     can have holes in the row (as the grain of the writeset is 
+     the column and not the entire row).
+   */
+  if (skip >= table->s->fields || !check)
     DBUG_RETURN(0);
 
-  /* Explicit initialization of fields */
+  /* Checking if exists default/nullable fields in the default values. */
 
   for (Field **field_ptr= table->field+skip ; *field_ptr ; ++field_ptr)
   {
     uint32 const mask= NOT_NULL_FLAG | NO_DEFAULT_VALUE_FLAG;
     Field *const f= *field_ptr;
 
-    if (check && ((f->flags & mask) == mask))
+    if (((f->flags & mask) == mask))
     {
       my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), f->field_name);
       error = HA_ERR_ROWS_EVENT_APPLY;
     }
-    else
-      f->set_default();
   }
 
   DBUG_RETURN(error);