Bug #73245 [Asn]: session_start() doesn't start the session if headers have been sent

Edit report at https://bugs.php.net/bug.php?id=73245&edit=1 ID: 73245 Updated by: yohgaki@php.net Reported by: php at duncanc dot co dot uk Summary: session_start() doesn't start the session if headers have been sent Status: Assigned Type: Bug Package: Session related Operating System: Linux PHP Version: 7.1.0RC3 Assigned To: yohgaki Block user comment: N Private report: N New Comment: Not initializing $_SESSION by 2nd session_start() is not a bug actually, but it should fail to initialize $_SESSION always when session_start() cannot be started. This is the objective for the bug fix commit mentioned. So real bug here is session module initializes $_SESSION even if it failed to start when there is no output before 1st session_start(). This report's bug won't be fixed. I re-opened bug #71038. Previous Comments: ------------------------------------------------------------------------ [2016-10-06 08:05:58] yohgaki@php.net Related To: Bug #71038 ------------------------------------------------------------------------ [2016-10-05 15:02:37] cmb@php.net Indeed, it appears to break only if there is already some output before the first session_start(). Try: <?php echo "start\n"; session_start(); $_SESSION['blah'] = 'foo'; var_dump($_SESSION); session_write_close(); session_start(); var_dump($_SESSION); ------------------------------------------------------------------------ [2016-10-05 12:17:25] yohgaki@php.net @cmd Thank you for investigation. I'll look into this, but it seems I need more info. It works for me... Perhaps, SAPI involved? [yohgaki@dev PHP-7.1]$ ./php-bin <?php session_start(); $_SESSION['blah'] = 'foo'; var_dump($_SESSION); session_write_close(); session_start(); var_dump($_SESSION); ?> array(1) { ["blah"]=> string(3) "foo" } Warning: session_start(): Cannot send session cookie - headers already sent by (output started at -:4) in - on line 7 Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at -:4) in - on line 7 array(1) { ["blah"]=> string(3) "foo" } ------------------------------------------------------------------------ [2016-10-05 10:51:30] cmb@php.net According to git bisect the offending commit is <https://github.com/php/php-src/commit/c200e8e1>. Yasuo, can you please have a look at this issue. ------------------------------------------------------------------------ [2016-10-04 17:40:56] php at duncanc dot co dot uk Description: ------------ In 7.0 and 5.6 calling session_start() even if headers have been sent still made $_SESSION usable, but 7.1 changes this behaviour. Test script: --------------- session_start(); $_SESSION['blah'] = 'foo'; var_dump($_SESSION); session_write_close(); session_start(); var_dump($_SESSION); Expected result: ---------------- The dumped array should be the same both times: array(1) { ["blah"]=> string(3) "foo" } Actual result: -------------- The second array dump is empty ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=73245&edit=1