ORDER BY could cause a server crash

Dependent subqueries like

  SELECT COUNT(*) FROM t1, t2 WHERE t2.b
   IN (SELECT DISTINCT t2.b FROM t2 WHERE t2.b = t1.a)

caused a memory leak proportional to the
number of outer rows.


The make_simple_join() function has been modified to
JOIN class method to store join_tab_reexec and
table_reexec values in the parent join only
(make_simple_join of tmp_join may access these values
via 'this' pointer of the parent JOIN).

NOTE: this patch doesn't include standard test case (this is
"out of memory" bug). See bug #42037 page for test cases.

Problem: some queries using NAME_CONST(.. COLLATE ...)
lead to server crash due to failed type cast.

Fix: return the underlying item's type in case of
NAME_CONST(.. COLLATE ...) to avoid wrong casting.

Accessing well defined MERGE table may return an error
stating that the merge table is incorrectly defined. This
happens if MERGE child tables were accessed before and we
failed to open another incorrectly defined MERGE table in
this connection.

myrg_open() internally used my_errno as a variable for determining
failure, and thus could be tricked into a wrong decision by other
uses of my_errno.

With this fix we use function local boolean flag instead of my_errno
to determine failure.

                    functions
      
String::realloc() did not check whether the existing string data fits in the newly
allocated buffer for cases when reallocating a String object with external buffer
(i.e.alloced == FALSE).  This could lead to memory overruns in some cases.

The original symptoms of this bug have been fixed as a consequence of other bug fixes.
Taking this time to correct some formatting, such as replacing error numbers with names.
Beginning this with 5.0

   - If missing: add "disconnect <session>"
   - If physical disconnect of non "default" sessions is not finished
     at test end: add routine which waits till this happened
+ additional improvements like
  - remove superfluous files created by the test
  - replace error numbers by error names
  - remove trailing spaces, replace tabs by spaces
  - unify writing of bugs within comments
  - correct comments
  - minor changes of formatting
Modifications according to the code review are included.
Fixed tests:
grant2
grant3
lock_tables_lost_commit
mysqldump
openssl_1
outfile

When storing a NULL to a TIMESTAMP NOT NULL DEFAULT ...,
NULL returned from some functions threw a 'cannot be NULL error.'

NULL-returns now correctly result in the timestamp-field being
assigned its default value.

            
If the system time is adjusted back during a query execution
(resulting in the end time being earlier than the start time)
the code that prints to the slow query log gets confused and 
prints unsigned negative numbers.
            
Fixed by not logging the statements that would have negative
execution time due to time shifts.
No test case since this would involve changing the system time.

            messed up

"ROW(...) IN (SELECT ... FROM DUAL)" always returned TRUE.

Item_in_subselect::row_value_transformer rewrites "ROW(...)
IN SELECT" conditions into the "EXISTS (SELECT ... HAVING ...)"
form.
For a subquery from the DUAL pseudotable resulting HAVING
condition is an expression on constant values, so further
transformation with optimize_cond() eliminates this HAVING
condition and resets JOIN::having to NULL.
Then JOIN::exec treated that NULL as an always-true-HAVING
and that caused a bug.

To distinguish an optimized out "HAVING TRUE" clause from
"HAVING FALSE" we already have the JOIN::having_value flag.
However, JOIN::exec() ignored JOIN::having_value as described
above as if it always set to COND_TRUE.

The JOIN::exec method has been modified to take into account
the value of the JOIN::having_value field.

Dirty close tricky does not work on Windows.

      
Re-generated the PKI files needed.
Removed the ones that are not needed.
Updated the tests to reference the correct SSL subject.

Check for existence of diff fails on Solaris due to unsupported "-v"
Fix is to do this check only on Windows where it was needed

packages, this is now corrected (Bug#42278)

The problem is that the query cache was storing partial results
if the statement failed when sending the results to the client.
This could cause clients to hang when trying to read the results
from the cache as they would, for example, wait indefinitely for
a eof packet that wasn't saved.

The solution is to always discard the caching of a query that
failed to send its results to the associated client.

This is not the final merge of that release build, but we need early
access to these tool fixes (use of "awk" in the BDB configuration).

with mysql_change_user) to 5.0.

Views weren't sync()d the same way other structures were.

In creating the FRM for views, obey the same rules for variable 
"sync_frm" as for everything else.

The problem is that the query cache stores packets containing
the server status of the time when the cached statement was run.
This might lead to a wrong transaction status in the client side
if a statement is cached during a transaction and is later served
outside a transaction context (and vice-versa).

The solution is to take into account the transaction status when
storing in and serving from the query cache.

The default "awk" there cannot handle some of the scripts
which are used by BDB for configuration.

The fix:
1) Introduce a variable "AWK" in some of the BDB shell scripts,
2) search "gawk" and give it precedence over "awk"
   when assigning a value to the "AWK" variable,
   fail if neither is found,
3) use that variable when calling an "awk" program with one
   of the critical scripts.

The perfect solution would be to use the "awk" program found
by "configure", but we cannot follow that approach because
BDB's configuration is handled as a special case before the
overall "configure" is run. Because of this,
1) the "configure" result isn't yet available,
2) "configure" will not handle these BDB files.
Searching "gawk" is a (not-so-nice) way out.

Note that all this need not be perfectly portable,
it is needed only when we create a source distribution tarball
from a develkopment tree.