BUG#49618: Field length stored incorrectly in binary log

           for InnoDB

The class Field_bit_as_char stores the metadata for the
field incorrecly because bytes_in_rec and bit_len are set
to (field_length + 7 ) / 8 and 0 respectively, while
Field_bit has the correct values field_length / 8 and
field_length % 8.

Solved the problem by re-computing the values for the
metadata based on the field_length instead of using the
bytes_in_rec and bit_len variables.

To handle compatibility with old server, a table map
flag was added to indicate that the bit computation is
exact. If the flag is clear, the slave computes the
number of bytes required to store the bit field and
compares that instead, effectively allowing replication
*without conversion* from any field length that require
the same number of bytes to store.

mysql-test/suite/rpl/t/rpl_typeconv_innodb.test:
  Adding test to check compatibility for bit field
  replication when using InnoDB.
sql/field.cc:
  Extending compatible_field_size() with flags from
  table map to allow fields to check master info.
sql/field.h:
  Extending compatible_field_size() with flags from
  table map to allow fields to check master info.
sql/log.cc:
  Removing table map flags since they are not used
  outside table map class.
sql/log_event.cc:
  Removing flags parameter from table map constructor
  since it is not used and does not have to be exposed.
sql/log_event.h:
  Adding flag to denote that bit length for bit field type
  is exact and not potentially rounded to even bytes.
sql/rpl_utility.cc:
  Adding fields to table_def to store table map flags.
sql/rpl_utility.h:
  Removing obsolete comment and adding flags to store
  table map flags from master.

1 files changed, 11 insertions, 5 deletions

diff --git a/sql/rpl_utility.cc b/sql/rpl_utility.cc
index 9d26c133279..6d30a8bc99f 100644
--- a/sql/rpl_utility.cc
+++ b/sql/rpl_utility.cc
@@ -510,6 +510,9 @@ void show_sql_type(enum_field_types type, uint16 metadata, String *str)
 /**
    Check the order variable and print errors if the order is not
    acceptable according to the current settings.
+
+   @param order  The computed order of the conversion needed.
+   @param rli    The relay log info data structure: for error reporting.
  */
 bool is_conversion_ok(int order, Relay_log_info *rli)
 {
@@ -562,6 +565,7 @@ bool is_conversion_ok(int order, Relay_log_info *rli)
    @param[in] type     Source field type
    @param[in] metadata Source field metadata
    @param[in] rli      Relay log info (for error reporting)
+   @param[in] mflags   Flags from the table map event
    @param[out] order   Order between source field and target field
 
    @return @c true if conversion is possible according to the current
@@ -571,7 +575,8 @@ bool is_conversion_ok(int order, Relay_log_info *rli)
 static bool
 can_convert_field_to(Field *field,
                      enum_field_types source_type, uint16 metadata,
-                     Relay_log_info *rli, int *order_var)
+                     Relay_log_info *rli, uint16 mflags,
+                     int *order_var)
 {
   DBUG_ENTER("can_convert_field_to");
 #ifndef DBUG_OFF
@@ -588,7 +593,7 @@ can_convert_field_to(Field *field,
   if (field->real_type() == source_type)
   {
     DBUG_PRINT("debug", ("Base types are identical, doing field size comparison"));
-    if (field->compatible_field_size(metadata, rli, order_var))
+    if (field->compatible_field_size(metadata, rli, mflags, order_var))
       DBUG_RETURN(is_conversion_ok(*order_var, rli));
     else
       DBUG_RETURN(false);
@@ -765,7 +770,7 @@ table_def::compatible_with(THD *thd, Relay_log_info *rli,
   {
     Field *const field= table->field[col];
     int order;
-    if (can_convert_field_to(field, type(col), field_metadata(col), rli, &order))
+    if (can_convert_field_to(field, type(col), field_metadata(col), rli, m_flags, &order))
     {
       DBUG_PRINT("debug", ("Checking column %d -"
                            " field '%s' can be converted - order: %d",
@@ -937,9 +942,10 @@ TABLE *table_def::create_conversion_table(THD *thd, Relay_log_info *rli, TABLE *
 
 table_def::table_def(unsigned char *types, ulong size,
                      uchar *field_metadata, int metadata_size,
-                     uchar *null_bitmap)
+                     uchar *null_bitmap, uint16 flags)
   : m_size(size), m_type(0), m_field_metadata_size(metadata_size),
-    m_field_metadata(0), m_null_bits(0), m_memory(NULL)
+    m_field_metadata(0), m_null_bits(0), m_flags(flags),
+    m_memory(NULL)
 {
   m_memory= (uchar *)my_multi_malloc(MYF(MY_WME),
                                      &m_type, size,