Description:
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---
From manual page: https://php.net/function.session-start
---
Request A and B are sent from the same browser at the same time (A prior to B) and use the same cookie.
A destroys session and B writes session in sequence.
B is blocked on 'session_start' and resumes after A destroys the session, but it does not create session or save the session variables.



Test script:
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request A:
        session_start();
        sleep(5);
        session_destroy();

request B:
        // B will be blocked by A on the session file
        session_start(); // !!!return ok but not session file!!!
        // resume until A destroys(releases) it. but no session file and the 'uid' cannot save.
        $_SESSION["uid"] = 1;
        


Expected result:
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The session file exists and session variable 'uid' is saved.

Actual result:
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No session file.