Bug #54334 [NEW]: The behavior for rounding to small presicion was changed and is against RFC

From: Operating system: Intel Linux and Intel MacOSX PHP version: 5.3.6 Package: Math related Bug Type: Bug Bug description:The behavior for rounding to small presicion was changed and is against RFC Description: ------------ The behavior of function round() was changed with revision 301991. So when a small number is rounded to small precision, round() of PHP5.3.4-5.3.6 returns different value from PHP5.3.0-5.3.3. Additionally, the current behavior is different from referred RFC(*1). I suppose it is not intended change. For example, test script returns "float(4.0E-60)" for PHP 5.3.0-5.3.3 and PHP 5.2.17. However, PHP 5.3.4-5.3.6 shows "float(3.0E-60)". This behavior changing was affected with revision 301991(*2) for fixing Bug #52550(*3). However, I think this fix was useless. Bug #52550 reports probability for integer overflow/underflow. However, the C function php_intlog10abs() returns integer between -324 and 308 because of property for IEEE754 64bit floating point numbers, so overflow/underflow never occur for this part. *1 http://wiki.php.net/rfc/rounding *2 http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3/ext/standard/math.c?r1=301991&r2=301990&pathrev=301991 *3 http://bugs.php.net/bug.php?id=52550 Test script: --------------- <?php var_dump(round(3.5e-60, 60)); Expected result: ---------------- float(4.0E-60) Actual result: -------------- float(3.0E-60) -- Edit bug report at http://bugs.php.net/bug.php?id=54334&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=54334&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=54334&r=trysnapshot53 Try a snapshot (trunk): http://bugs.php.net/fix.php?id=54334&r=trysnapshottrunk Fixed in SVN: http://bugs.php.net/fix.php?id=54334&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=54334&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=54334&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=54334&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=54334&r=needscript Try newer version: http://bugs.php.net/fix.php?id=54334&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=54334&r=support Expected behavior: http://bugs.php.net/fix.php?id=54334&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=54334&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=54334&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=54334&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=54334&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=54334&r=dst IIS Stability: http://bugs.php.net/fix.php?id=54334&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=54334&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=54334&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=54334&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=54334&r=mysqlcfg