Fix warnings flagged by the new warning option -Wunused-but-set-variable
that was added to GCC 4.6 and that is enabled by -Wunused and -Wall. The
option causes a warning whenever a local variable is assigned to but is
later unused. It also warns about meaningless pointer dereferences.
client/mysql.cc:
Meaningless pointer dereferences.
client/mysql_upgrade.c:
Check whether reading from the file succeeded.
extra/comp_err.c:
Unused.
extra/yassl/src/yassl_imp.cpp:
Skip instead of reading data that is discarded.
include/my_pthread.h:
Variable is only used in debug builds.
include/mysys_err.h:
Add new error messages.
mysys/errors.c:
Add new error message for permission related functions.
mysys/mf_iocache.c:
Variable is only checked under THREAD.
mysys/my_copy.c:
Raise a error if chmod or chown fails.
mysys/my_redel.c:
Raise a error if chmod or chown fails.
regex/engine.c:
Use a equivalent variable for the assert.
server-tools/instance-manager/instance_options.cc:
Unused.
sql/field.cc:
Unused.
sql/item.cc:
Unused.
sql/log.cc:
Do not ignore the return value of freopen: only set buffer if
reopening succeeds.
Adjust doxygen comment to the right function.
Pass message lenght to log function.
sql/mysqld.cc:
Do not ignore the return value of freopen: only set buffer if
reopening succeeds.
sql/partition_info.cc:
Unused.
sql/slave.cc:
No need to set pointer to the address of '\0'.
sql/spatial.cc:
Unused. Left for historical purposes.
sql/sql_acl.cc:
Unused.
sql/sql_base.cc:
Pointers are always set to the same variables.
sql/sql_parse.cc:
End statement if reading fails.
Store the buffer after it has actually been updated.
sql/sql_repl.cc:
No need to set pointer to the address of '\0'.
sql/sql_show.cc:
Put variable under the same ifdef block.
sql/udf_example.c:
Set null pointer flag appropriately.
storage/csv/ha_tina.cc:
Meaningless dereferences.
storage/example/ha_example.cc:
Return the error since it's available.
storage/myisam/mi_locking.c:
Remove unused and dead code.
Although the C standard mandates that sprintf return the number
of bytes written, some very ancient systems (i.e. SunOS 4)
returned a pointer to the buffer instead. Since these systems
are not supported anymore and are hopefully long dead by now,
simply remove the portability wrapper that dealt with this
discrepancy. The autoconf check was causing trouble with GCC.
The server was not cleaning up some dbug allocated memory
before exiting. This is not a real problem, as this memory
would be deallocated anyway. Nonetheless, we improve the
mysqlbinlog exit procedure, wrt to memory book-keeping, when
no parameter is given.
To fix this, we deploy a call to my_end() before the
thread exits.
Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.
Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.
Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost.
The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.
Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.
client/mysqldump.c:
Pass my_free directly as its signature is compatible with the
callback type -- which wasn't the case for free_table_ent.
The server was not cleaning up dbug allocated memory before
exiting. This is not a real problem, as this memory would be
deallocated anyway. Nonetheless, we improve the mysqlbinlog exit
procedure, wrt to memory book-keeping, when no parameter is
given.
To fix this, we deploy a call to my_thread_end() before the
thread exits, which will also free pending dbug related allocated
blocks.
Apart strict-aliasing warnings, fix the remaining warnings
generated by GCC 4.4.4 -Wall and -Wextra flags.
One major source of warnings was the in-house function my_bcmp
which (unconventionally) took pointers to unsigned characters
as the byte sequences to be compared. Since my_bcmp and bcmp
are deprecated functions whose only difference with memcmp is
the return value, every use of the function is replaced with
memcmp as the special return value wasn't actually being used
by any caller.
There were also various other warnings, mostly due to type
mismatches, missing return values, missing prototypes, dead
code (unreachable) and ignored return values.
BUILD/SETUP.sh:
Remove flags that are implied by -Wall and -Wextra.
Do not warn about unused parameters in C++.
BUILD/check-cpu:
Print only the compiler version instead of verbose banner.
Although the option is gcc specific, the check was only
being used for GCC specific checks anyway.
client/mysql.cc:
bcmp is no longer defined.
client/mysqltest.cc:
Pass a string to function expecting a format string.
Replace use of bcmp with memcmp.
cmd-line-utils/readline/Makefile.am:
Always define _GNU_SOURCE when compiling GNU readline.
Required to make certain prototypes visible.
cmd-line-utils/readline/input.c:
Condition for the code to be meaningful.
configure.in:
Remove check for bcmp.
extra/comp_err.c:
Use appropriate type.
extra/replace.c:
Replace use of bcmp with memcmp.
extra/yassl/src/crypto_wrapper.cpp:
Do not ignore the return value of fgets. Retrieve the file
position if fgets succeed -- if it fails, the function will
bail out and return a error.
extra/yassl/taocrypt/include/blowfish.hpp:
Use a single array instead of accessing positions of the sbox_
through a subscript to pbox_.
extra/yassl/taocrypt/include/runtime.hpp:
One definition of such functions is enough.
extra/yassl/taocrypt/src/aes.cpp:
Avoid potentially ambiguous conditions.
extra/yassl/taocrypt/src/algebra.cpp:
Rename arguments to avoid shadowing related warnings.
extra/yassl/taocrypt/src/blowfish.cpp:
Avoid potentially ambiguous conditions.
extra/yassl/taocrypt/src/integer.cpp:
Do not define type within a anonymous union.
Use a variable to return a value instead of
leaving the result in a register -- compiler
does not know the logic inside the asm.
extra/yassl/taocrypt/src/misc.cpp:
Define handler for pure virtual functions.
Remove unused code.
extra/yassl/taocrypt/src/twofish.cpp:
Avoid potentially ambiguous conditions.
extra/yassl/testsuite/test.hpp:
Function must have C language linkage.
include/m_string.h:
Remove check which relied on bcmp being defined -- they weren't
being used as bcmp is only visible when _BSD_SOURCE is defined.
include/my_bitmap.h:
Remove bogus helpers which were used only in a few files and
were causing warnings about dead code.
include/my_global.h:
Due to G++ bug, always silence false-positive uninitialized
variables warnings when compiling C++ code with G++.
Remove bogus helper.
libmysql/Makefile.shared:
Remove built-in implementation of bcmp.
mysql-test/lib/My/SafeProcess/safe_process.cc:
Cast pid to largest possible type for a process identifier.
mysys/mf_loadpath.c:
Leave space of the ending nul.
mysys/mf_pack.c:
Replace bcmp with memcmp.
mysys/my_bitmap.c:
Dead code removal.
mysys/my_gethwaddr.c:
Remove unused variable.
mysys/my_getopt.c:
Silence bogus uninitialized variable warning.
Do not cast away the constant qualifier.
mysys/safemalloc.c:
Cast to expected type.
mysys/thr_lock.c:
Silence bogus uninitialized variable warning.
sql/field.cc:
Replace bogus helper with a more appropriate logic which is
used throughout the code.
sql/item.cc:
Remove bogus logical condition which always evaluates to TRUE.
sql/item_create.cc:
Simplify code to avoid signedness related warnings.
sql/log_event.cc:
Replace use of bcmp with memcmp.
No need to use helpers for simple bit operations.
sql/log_event_old.cc:
Replace bmove_align with memcpy.
sql/mysqld.cc:
Move use declaration of variable to the ifdef block where it
is used. Remove now-unnecessary casts and arguments.
sql/set_var.cc:
Replace bogus helpers with simple and classic bit operations.
sql/slave.cc:
Cast to expected type and silence bogus warning.
sql/sql_class.h:
Don't use enum values as bit flags, the supposed type safety is
bogus as the combined bit flags are not a value in the enumeration.
sql/udf_example.c:
Only declare variable when necessary.
sql/unireg.h:
Replace use of bmove_align with memcpy.
storage/innobase/os/os0file.c:
Silence bogus warning.
storage/myisam/mi_open.c:
Remove bogus cast, DBUG_DUMP expects a pointer to unsigned
char.
storage/myisam/mi_page.c:
Remove bogus cast, DBUG_DUMP expects a pointer to unsigned
char.
strings/bcmp.c:
Remove built-in bcmp.
strings/ctype-ucs2.c:
Silence bogus warning.
tests/mysql_client_test.c:
Use a appropriate type as expected by simple_command().
strict aliasing violations.
Essentially, the problem is that large parts of the server were
developed in simpler times (last decades, pre C99 standard) when
strict aliasing and compilers supporting such optimizations were
rare to non-existent. Thus, when compiling the server with a modern
compiler that uses strict aliasing rules to perform optimizations,
there are several places in the code that might trigger undefined
behavior.
As evinced by some recent bugs, GCC does a somewhat good of job
misoptimizing such code, but on the other hand also gives warnings
about suspicious code. One problem is that the warnings aren't
always accurate, yet we can't afford to just shut them off as we
might miss real cases. False-positive cases are aggravated mostly
by casts that are likely to trigger undefined behavior.
The solution is to start a cleanup process focused on fixing and
reducing the amount of strict-aliasing related warnings produced
by GCC and others compilers. A good deal of noise reduction can
be achieved by just removing useless casts that are product of
historical cruft and are likely to trigger undefined behavior if
dereferenced.
client/mysql.cc:
Remove now-unnecessary casts.
Break up large strings.
client/mysql_upgrade.c:
Remove now-unnecessary casts.
client/mysqladmin.cc:
Remove now-unnecessary casts.
Break up large strings.
client/mysqlbinlog.cc:
Remove now-unnecessary casts.
client/mysqlcheck.c:
Remove now-unnecessary casts.
client/mysqldump.c:
Remove now-unnecessary casts.
client/mysqlimport.c:
Remove now-unnecessary casts.
client/mysqlshow.c:
Remove now-unnecessary casts.
client/mysqlslap.c:
Remove now-unnecessary casts.
client/mysqltest.cc:
Remove now-unnecessary casts.
extra/comp_err.c:
Remove now-unnecessary casts.
extra/my_print_defaults.c:
Remove now-unnecessary casts.
Break up large strings.
extra/mysql_waitpid.c:
Remove now-unnecessary casts.
extra/perror.c:
Remove now-unnecessary casts.
extra/resolve_stack_dump.c:
Remove now-unnecessary casts.
extra/resolveip.c:
Remove now-unnecessary casts.
include/my_getopt.h:
Use a void pointer type as the opaque type to avoid problems with type
incompatibility -- GCC issues warnings when the type name is not type
compatible with a operand. As a side bonus, a explicit cast won't be
necessary anymore.
include/sslopt-longopts.h:
Remove now-unnecessary casts.
Break up large strings.
mysys/my_getopt.c:
Update opaque type and introduce a type definition for the
argument to my_getopt_register_get_addr.
server-tools/instance-manager/options.cc:
Remove now-unnecessary casts.
sql/mysqld.cc:
Remove now-unnecessary casts.
Break up large strings.
Update mysql_getopt_value prototype (the old prototype
was different from the definition anyway).
sql/sql_plugin.cc:
The type of a pointer to a function must be compatible with the
pointed-to function type, otherwise the behavior is undefined.
sql/table.cc:
The variable buf pointer to pointer to pointer to constant char
could improperly alias a incompatible type in call to fix_type_
pointers. Since this was actually dead code, it is simply removed.
sql/unireg.cc:
Remove call to get_form_pos. The code creates a new FRM file which
is always truncated and writes the form position as 0. Hence, no
need to retrieve it, we now for sure it is 0.
storage/archive/archive_reader.c:
Remove now-unnecessary casts.
storage/myisam/ft_nlq_search.c:
Read weight directly from the buffer.
storage/myisam/fulltext.h:
Add explanation about the type duality of a key buffer.
Add accessor macro to retrieve a FT float value.
storage/myisam/mi_test1.c:
Remove now-unnecessary casts.
storage/myisam/myisam_ftdump.c:
Read weight directly from the buffer.
storage/myisam/myisamchk.c:
Remove now-unnecessary casts.
storage/myisam/myisamlog.c:
A pointer to char was used to alias a pointer to pointer to
unsigned char, thus violating strict aliasing rules.
storage/myisam/myisampack.c:
Remove now-unnecessary casts.
strings/decimal.c:
Remove aliasing violation, printing the value is enough for
debugging purposes.
tests/mysql_client_test.c:
Remove now-unnecessary casts.
Also, update a few cases missed by the initial patch.
client/mysqltest.cc:
Remove trailing comma.
include/my_alloc.h:
Do not use wrapper.
include/mysql.h.pp:
Update ABI file.
plugin/semisync/semisync_master.h:
Initialize variable.
sql/debug_sync.cc:
Use C linkage.
Fix various mismatches between function's language linkage. Any
particular function that is declared in C++ but should be callable
from C must have C linkage. Note that function types with different
linkages are also distinct. Thus, if a function type is declared in
C code, it will have C linkage (same if declared in a extern "C"
block).
client/mysql.cc:
Mismatch between prototype and declaration.
client/mysqltest.cc:
mysqltest used to be C code. Use C linkage where appropriate.
cmd-line-utils/readline/input.c:
Isolate unreachable code.
include/my_alloc.h:
Function type must have C linkage.
include/my_base.h:
Function type must have C linkage.
include/my_global.h:
Add helper macros to avoid spurious namespace indentation.
include/mysql.h.pp:
Update ABI file.
mysys/my_gethwaddr.c:
Remove stray carriage return and fix coding style.
plugin/semisync/semisync_master_plugin.cc:
Callback function types have C linkage.
plugin/semisync/semisync_slave_plugin.cc:
Callback function types have C linkage.
sql/derror.cc:
Expected function type has C linkage.
sql/field.cc:
Use helper macro and fix indentation.
sql/handler.cc:
Expected function type has C linkage.
sql/item_sum.cc:
Correct function linkages. Remove now unnecessary cast.
sql/item_sum.h:
Add prototypes with the appropriate linkage as otherwise they
are distinct.
sql/mysqld.cc:
Wrap functions in C linkage mode.
sql/opt_range.cc:
C language linkage is ignored for class member functions.
sql/partition_info.cc:
Add wrapper functions with C linkage for class member functions.
sql/rpl_utility.h:
Use helper macro and fix indentation.
sql/sql_class.cc:
Change type of thd argument -- THD is a class.
Use helper macro and fix indentation.
sql/sql_class.h:
Change type of thd argument -- THD is a class.
sql/sql_select.cc:
Expected function type has C linkage.
sql/sql_select.h:
Move prototype to sql_test.h
sql/sql_show.cc:
Expected function type has C linkage.
sql/sql_test.cc:
Fix required function prototype and fix coding style.
sql/sql_test.h:
Removed unnecessary export and add another.
storage/myisammrg/ha_myisammrg.cc:
Expected function type has C linkage.
storage/perfschema/pfs.cc:
PSI headers are declared with C language linkage, which also
applies to function types.
(make relies GNU extentions). The patch was partially
backport from 6.0.
Original comment:
bug#30708: make relies GNU extensions. Now that we no longer use
BitKeeper we can safely remove the SCCS handling with no loss of
functionality.
ChangeSet@1.2703, 2007-12-07 09:35:28-05:00, cmiller@zippy.cornsilk.net +40 -0
Bug#13174: SHA2 function
Patch contributed from Bill Karwin, paper unnumbered CLA in Seattle
Implement SHA2 functions.
Chad added code to make it work with YaSSL. Also, he removed the
(probable) bug of embedded server never using SSL-dependent
functions. (libmysqld/Makefile.am didn't read ANY autoconf defs.)
Function specification:
SHA2( string cleartext, integer hash_length )
-> string hash, or NULL
where hash_length is one of 224, 256, 384, or 512. If either is
NULL or a length is unsupported, then the result is NULL. The
resulting string is always the length of the hash_length parameter
or is NULL.
Include the canonical hash examples from the NIST in the test
results.
---
Polish and address concerns of reviewers.
.bzrignore:
Added libmysqld/sha2.cc to the ignore list.
client/mysql.cc:
Add condition to remove code for embedded server.
client/mysqltest.cc:
Add condition to remove code for embedded server.
include/Makefile.am:
New header file to header list.
include/mysql_embed.h:
Embedded servers can use SSL-library functions too!
include/sha2.h:
Compatibility layer to make YaSSL behave like OpenSSL.
include/sslopt-case.h:
Remove SSL-communication parameters from command lines.
include/sslopt-longopts.h:
Remove SSL-communication parameters from command lines.
include/sslopt-vars.h:
Don't declare variables that are only used in SSL communication, if
we are compiling the embedded server.
include/violite.h:
Don't even compile the SSL-communication function if we're in the
embedded server.
---
Remove CPP condition indentation.
libmysqld/CMakeLists.txt:
Add new file to source list.
libmysqld/Makefile.am:
Include standard DEFS in embedded compilation. It's an undiscovered
but that it's not there.
Add new file to source list.
libmysqld/examples/Makefile.am:
Include autoconf DEFS.
libmysqld/lib_sql.cc:
Initialize SSL-related variables in embedded server.
mysql-test/include/have_ssl_crypto_functs.inc:
Distinguish between communication and crypto.
Use the tristate value of "have_ssl" variable to know whether to
test or not for SSL-provided crypto functions.
mysql-test/r/func_digest.result:
Test against the sample test vectors in the NIST Secure
Hash Standard (http://csrc.nist.gov/cryptval/shs.htm)
mysql-test/r/func_encrypt_nossl.result:
Update results to the new error message text.
mysql-test/r/have_ssl_is_yes_or_disabled_only.require:
Distinguish between communication and crypto.
Use the tristate value of "have_ssl" variable to know whether to
test or not for SSL-provided crypto functions.
mysql-test/suite/rpl/t/rpl_ssl.test:
Distinguish between communication and crypto.
mysql-test/suite/rpl/t/rpl_ssl1.test:
Distinguish between communication and crypto.
mysql-test/t/func_des_encrypt.test:
Distinguish between communication and crypto.
mysql-test/t/func_digest.test:
Test against the sample test vectors in the NIST Secure
Hash Standard (http://csrc.nist.gov/cryptval/shs.htm)
Also, test that various parameters (legal and illegal)
do what we expect.
---
Distinguish between communication and crypto.
mysql-test/t/func_encrypt.test:
Distinguish between communication and crypto.
mysql-test/t/openssl_1.test:
Don't test SSL communication if we're in the embedded server.
---
Distinguish between communication and crypto.
mysql-test/t/ssl-big.test:
Don't test SSL communication if we're in the embedded server.
---
Distinguish between communication and crypto.
mysql-test/t/ssl.test:
Don't test SSL communication if we're in the embedded server.
---
Distinguish between communication and crypto.
mysql-test/t/ssl_8k_key.test:
Don't test SSL communication if we're in the embedded server.
---
Distinguish between communication and crypto.
mysql-test/t/ssl_compress.test:
Don't test SSL communication if we're in the embedded server.
---
Distinguish between communication and crypto.
mysql-test/t/ssl_connect.test:
Don't test SSL communication if we're in the embedded server.
---
Distinguish between communication and crypto.
sql-common/client.c:
SSL is useful for more functionality than just connecting. Test
for whether we are not embedded server also.
sql/CMakeLists.txt:
Add new source file to source list so that we have access to SHA2
functions.
sql/Makefile.am:
Add new source file to source list so that we have access to SHA2
functions.
sql/item_create.cc:
Bootstrap the SHA2 function into the server.
sql/item_strfunc.cc:
Add new SHA2 Item class methods.
Clean up two minor problems.
---
Remove extraneous debugging.
---
We must check nullness of a parameter only /after/ computing its
value.
sql/item_strfunc.h:
Declare new SHA2 Item class.
sql/mysqld.cc:
For embedded server, don't refer to SSL-communications variables
or values.
---
Remove CPP condition indentation.
sql/sha2.cc:
Compatibility layer to make YaSSL behave like OpenSSL.
---
Add comment for generated functions.
sql/sql_acl.cc:
For embedded server, don't refer to SSL-communications variables
or values.
sql/sql_connect.cc:
SSL is useful for more functionality than just connecting. Test
for whether we are not embedded server also.
sql/sys_vars.cc:
For embedded server, don't refer to SSL-communications variables
or values.
Conflicts:
Text conflict in mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result
Text conflict in sql/log.cc
Text conflict in sql/set_var.cc
Text conflict in sql/sql_class.cc
This patch:
- Moves all definitions from the mysql_priv.h file into
header files for the component where the variable is
defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h
Conflicts:
Text conflict in client/mysqlbinlog.cc
Text conflict in mysql-test/Makefile.am
Text conflict in mysql-test/collections/default.daily
Text conflict in mysql-test/r/mysqlbinlog_row_innodb.result
Text conflict in mysql-test/suite/rpl/r/rpl_typeconv_innodb.result
Text conflict in mysql-test/suite/rpl/t/rpl_get_master_version_and_clock.test
Text conflict in mysql-test/suite/rpl/t/rpl_row_create_table.test
Text conflict in mysql-test/suite/rpl/t/rpl_slave_skip.test
Text conflict in mysql-test/suite/rpl/t/rpl_typeconv_innodb.test
Text conflict in mysys/charset.c
Text conflict in sql/field.cc
Text conflict in sql/field.h
Text conflict in sql/item.h
Text conflict in sql/item_func.cc
Text conflict in sql/log.cc
Text conflict in sql/log_event.cc
Text conflict in sql/log_event_old.cc
Text conflict in sql/mysqld.cc
Text conflict in sql/rpl_utility.cc
Text conflict in sql/rpl_utility.h
Text conflict in sql/set_var.cc
Text conflict in sql/share/Makefile.am
Text conflict in sql/sql_delete.cc
Text conflict in sql/sql_plugin.cc
Text conflict in sql/sql_select.cc
Text conflict in sql/sql_table.cc
Text conflict in storage/example/ha_example.h
Text conflict in storage/federated/ha_federated.cc
Text conflict in storage/myisammrg/ha_myisammrg.cc
Text conflict in storage/myisammrg/myrg_open.c
When mysqlbinlog was given the --database=X flag, it always printed
'ROLLBACK TO', but the corresponding 'SAVEPOINT' statement was not
printed. The replicated filter(replicated-do/ignore-db) and binlog
filter (binlog-do/ignore-db) has the same problem. They are solved
in this patch together.
After this patch, We always check whether the query is 'SAVEPOINT'
statement or not. Because this is a literal check, 'SAVEPOINT' and
'ROLLBACK TO' statements are also binlogged in uppercase with no
any comments.
The binlog before this patch can be handled correctly except one case
that any comments are in front of the keywords. for example:
/* bla bla */ SAVEPOINT a;
/* bla bla */ ROLLBACK TO a;
Conflicts:
Text conflict in client/mysqlbinlog.cc
Text conflict in mysql-test/r/explain.result
Text conflict in mysql-test/r/subselect.result
Text conflict in mysql-test/r/subselect3.result
Text conflict in mysql-test/r/type_datetime.result
Text conflict in sql/share/Makefile.am
Before this fix, client tools (mysql_upgrade, mysqlcheck, mysqldump)
would try to process performance schema tables, leading to failures.
The fix is to align FIRST_PERFORMANCE_SCHEMA_VERSION to 5.5.3,
which is the version number of mysql-trunk where the
performance schema is first available.
mysql_upgrade was passing an non-initialized non-null tmpdir to create_temp_file() if no
--tmpdir was specified. This prevents create_temp_file() from taking the system
temporary file path and as a result mysql_upgrade was trying to open a file in a
directory that it may not have write access to.
Fixed by making sure mysql_upgrade will pass a zero length temp dir string to
create_temp_file() if no --tmpdir is specified.
The problem was that mysqltest could attempt to execute a
SHOW WARNINGS statement through a connection that was not
properly reaped, thus violating its own rules.
The solution is to skip SHOW WARNINGS if a connection has
not been properly repeaed.
client/mysqltest.cc:
Skip SHOW WARNINGS if connection hasn't been reaped.
