Bug #76900 [NEW]: overwriting start of stream truncates the end

From: sjon at hortensius dot net Operating system: archLinux PHP version: 7.3.0RC1 Package: Streams related Bug Type: Bug Bug description:overwriting start of stream truncates the end Description: ------------ after fseeking a stream and fwriting less data to it, the previous available data is gone See https://3v4l.org/2haHa Test script: --------------- <?php $socket = fopen('php://memory', 'a+'); fwrite($socket, 'ab'); fseek($socket, 0); fwrite($socket, 'a'); var_dump(fgets($socket)); Expected result: ---------------- string(1) "b" Actual result: -------------- bool(false) -- Edit bug report at https://bugs.php.net/bug.php?id=76900&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=76900&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=76900&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=76900&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=76900&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=76900&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=76900&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=76900&r=needscript Try newer version: https://bugs.php.net/fix.php?id=76900&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=76900&r=support Expected behavior: https://bugs.php.net/fix.php?id=76900&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=76900&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=76900&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=76900&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=76900&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=76900&r=dst IIS Stability: https://bugs.php.net/fix.php?id=76900&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=76900&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=76900&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=76900&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=76900&r=mysqlcfg