Bug#42977 RBR logs for rows with more than 250 column results in corrupt binlog

            
The issue happened to be two-fold.
The table map event was recorded into binlog having
an incorrect size when number of columns exceeded 251. 
The Row-based event had incorrect recording and restoring m_width member within
the same as above conditions.

Fixed with correcting m_data_size and m_width.


mysql-test/suite/rpl/r/rpl_row_wide_table.result:
  the new test results.
mysql-test/suite/rpl/t/rpl_row_wide_table.test:
  regression test for bug#42977.
sql/log_event.cc:
  0. all buffers that used in net_store_length() are augmented with 1 for safety
  to be able to contain the magic and the content of ulonglong as well;
  1. Rows_log_event::get_data_size() yieled incorrect size |m_width/8| whereas 
     it should be m_width;
  2. Table_map_log_event::Table_map_log_event yieled incorrect value for
     `m_data_size' probably presuming 1-byte integer max for the column number;
sql/rpl_utility.h:
  DBUG_PRINT_BITSET() macro is left 256-cols limited but has made safe and commented.

1 files changed, 4 insertions, 2 deletions

diff --git a/sql/rpl_utility.h b/sql/rpl_utility.h
index 8e2f4a7374f..1f4ca246ff1 100644
--- a/sql/rpl_utility.h
+++ b/sql/rpl_utility.h
@@ -294,12 +294,14 @@ namespace {
 }
 #endif
 
+// NB. number of printed bit values is limited to sizeof(buf) - 1
 #define DBUG_PRINT_BITSET(N,FRM,BS)                \
   do {                                             \
     char buf[256];                                 \
-    for (uint i = 0 ; i < (BS)->n_bits ; ++i)      \
+    uint i;                                        \
+    for (i = 0 ; i < min(sizeof(buf) - 1, (BS)->n_bits) ; i++) \
       buf[i] = bitmap_is_set((BS), i) ? '1' : '0'; \
-    buf[(BS)->n_bits] = '\0';                      \
+    buf[i] = '\0';                                 \
     DBUG_PRINT((N), ((FRM), buf));                 \
   } while (0)