Fix for bug #31236: Inconsistent division by zero behavior for

                    floating point numbers

Some math functions did not check if the result is a valid number
(i.e. neither of +-inf or nan).

Fixed by validating the result where necessary and returning NULL in
case of invalid result.


BitKeeper/deleted/.del-matherr.c:
  Rename: sql/matherr.c -> BitKeeper/deleted/.del-matherr.c
configure.in:
  Removed DONT_USE_FINITE, it is not used anywhere.
include/my_global.h:
  isfinite() is a C99 macro which absoletes finite(). First try to use
  it, then fall back to finite() if the target platform has it,
  otherwise use our own implementation.
mysql-test/r/func_math.result:
  Added a test case for bug #31236.
mysql-test/r/strict.result:
  Fixed a test case which relied on old behavior.
mysql-test/t/func_math.test:
  Added a test case for bug #31236.
mysql-test/t/strict.test:
  Fixed a test case which relied on old behavior.
sql/field.cc:
  No need to check if the finite() or its equivalent is available.
sql/item_func.cc:
  Use fix_result() wherever the result can be one of +-inf or nan, 
  assuming the function arguments are valid numbers.
  Removed fix_result() from functions that are defined for all possible
  input numbers.
sql/item_func.h:
  Moved fix_result() from Item_dec_func to Item_func which is a common
  ancestor for Item_dec_func and Item_num_op.
sql/unireg.h:
  Removed POSTFIX_ERROR because no code returns it.

1 files changed, 0 insertions, 42 deletions

diff --git a/sql/matherr.c b/sql/matherr.c
deleted file mode 100644
index 4998d8b4961..00000000000
--- a/sql/matherr.c
+++ /dev/null
@@ -1,42 +0,0 @@
-/* Copyright (C) 2000-2001 MySQL AB
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; version 2 of the License.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
-
-/* Fix that we got POSTFIX_ERROR when doing unreasonable math (not core) */
-
-#include <my_global.h>
-#include <errno.h>
-
-	/* Fix that we gets POSTFIX_ERROR when error in math */
-
-#if defined(HAVE_MATHERR)
-int matherr(struct exception *x)
-{
-  if (x->type != PLOSS)
-    x->retval=POSTFIX_ERROR;
-  switch (x->type) {
-  case DOMAIN:
-  case SING:
-    my_errno=EDOM;
-    break;
-  case OVERFLOW:
-  case UNDERFLOW:
-    my_errno=ERANGE;
-    break;
-  default:
-    break;
-  }
-  return(1);					/* Take no other action */
-}
-#endif