Bug #74941 [NEW]: Session fails to start after having headers sent

From: smorozov at sugarcrm dot com Operating system: Linux PHP version: 7.2.0alpha3 Package: Session related Bug Type: Bug Bug description:Session fails to start after having headers sent Description: ------------ If a session start is not supposed to output any headers, it should not fail in the case if response headers have been already sent. The script below works on PHP 7.1 and older versions but doesn't work on PHP 7.2. The same happens when calling session_id($id) before session_start(). Seems similar to #55267. Test script: --------------- <?php ini_set('session.use_cookies', false); ini_set('session.cache_limiter', false); echo '.'; session_start(); Expected result: ---------------- No warning triggered. Actual result: -------------- Warning: session_start(): Cannot start session when headers already sent in test.php on line 8 Call Stack: 0.0001 397720 1. {main}() test.php:0 0.0001 398128 2. session_start() test.php:8 -- Edit bug report at https://bugs.php.net/bug.php?id=74941&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=74941&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=74941&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=74941&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=74941&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=74941&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=74941&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=74941&r=needscript Try newer version: https://bugs.php.net/fix.php?id=74941&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=74941&r=support Expected behavior: https://bugs.php.net/fix.php?id=74941&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=74941&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=74941&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=74941&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74941&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=74941&r=dst IIS Stability: https://bugs.php.net/fix.php?id=74941&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=74941&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=74941&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=74941&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=74941&r=mysqlcfg