BUG#22550 (Replication of BIT column failing):

Using move_field_offset() to move field pointer to other record before
calling pack()/unpack().

sql/log_event.cc

@@ -5375,7 +5375,9 @@ unpack_row(RELAY_LOG_INFO *rli,
 
     if (bitmap_is_set(cols, field_ptr -  begin_ptr))
     {
-      ptr= f->unpack(f->ptr + offset, ptr);
+      f->move_field_offset(offset);
+      ptr= f->unpack(f->ptr, ptr);
+      f->move_field_offset(-offset);
       /* Field...::unpack() cannot return 0 */
       DBUG_ASSERT(ptr != NULL);
     }
@@ -6675,6 +6677,7 @@ static int find_and_fetch_row(TABLE *table, byte *key)
         table->s->null_bytes > 0 ? table->s->null_bytes - 1 : 0;
       table->record[1][pos]= 0xFF;
       error= table->file->rnd_next(table->record[1]);
+
       switch (error)
       {
       case 0:
@@ -6956,6 +6959,10 @@ int Update_rows_log_event::do_prepare_row(THD *thd, RELAY_LOG_INFO *rli,
                     row_start, &m_cols, row_end, &m_master_reclength,
                     table->write_set, UPDATE_ROWS_EVENT);
 
+  DBUG_DUMP("record[0]", table->record[0], table->s->reclength);
+  DBUG_DUMP("m_after_image", m_after_image, table->s->reclength);
+
+
   /*
     If we will access rows using the random access method, m_key will
     be set to NULL, so we do not need to make a key copy in that case.

sql/sql_class.cc

@@ -2529,7 +2529,9 @@ my_size_t THD::pack_row(TABLE *table, MY_BITMAP const* cols, byte *row_data,
     {
       my_ptrdiff_t const offset=
         field->is_null(rec_offset) ? def_offset : rec_offset;
-      ptr= (byte*)field->pack((char *) ptr, field->ptr + offset);
+      field->move_field_offset(offset);
+      ptr= (byte*)field->pack((char *) ptr, field->ptr);
+      field->move_field_offset(-offset);
     }
   }
   return (static_cast<my_size_t>(ptr - row_data));
@@ -2614,12 +2616,19 @@ int THD::binlog_update_row(TABLE* table, bool is_trans,
   my_size_t const after_size= pack_row(table, cols, after_row, 
                                        after_record);
   
+  DBUG_DUMP("before_record", before_record, table->s->reclength);
+  DBUG_DUMP("after_record", after_record, table->s->reclength);
+  DBUG_DUMP("before_row", before_row, before_size);
+  DBUG_DUMP("after_row", after_row, after_size);
+
   Rows_log_event* const ev=
     binlog_prepare_pending_rows_event(table, server_id, cols, colcnt,
 				      before_size + after_size, is_trans,
 				      static_cast<Update_rows_log_event*>(0));
 
-  error= (unlikely(!ev)) || ev->add_row_data(before_row, before_size) ||
+  error=
+    unlikely(!ev) ||
+    ev->add_row_data(before_row, before_size) ||
     ev->add_row_data(after_row, after_size);
 
   if (!table->write_row_record)