Bug #75800 [NEW]: json_encode produces unexpected results with summed floats

From: yoch at yoch dot org Operating system: Ubuntu 16.04.3 LTS PHP version: 7.2.1 Package: JSON related Bug Type: Bug Bug description:json_encode produces unexpected results with summed floats Description: ------------ With default php.ini settings (serialize_precision = "-1" and precision = "14"), json_encode() produces inconsistent results. After setting serialize_precision to "14" serialization working as expected. Test script: --------------- php -r 'echo 2.09 + 0.4;' php -r 'echo json_encode(2.49);' php -r 'echo json_encode(2.09 + 0.4);' Expected result: ---------------- 2.49 2.49 2.49 Actual result: -------------- 2.49 2.49 2.4899999999999998 -- Edit bug report at https://bugs.php.net/bug.php?id=75800&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=75800&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=75800&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=75800&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=75800&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=75800&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=75800&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=75800&r=needscript Try newer version: https://bugs.php.net/fix.php?id=75800&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=75800&r=support Expected behavior: https://bugs.php.net/fix.php?id=75800&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=75800&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=75800&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=75800&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=75800&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=75800&r=dst IIS Stability: https://bugs.php.net/fix.php?id=75800&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=75800&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=75800&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=75800&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=75800&r=mysqlcfg