Bug #80088 [NEW]: c+ open mode messes up file on fwrite()

From: smitty7523 at yahoo dot com Operating system: Linux Manjaro PHP version: 7.4.10 Package: Filesystem function related Bug Type: Bug Bug description:c+ open mode messes up file on fwrite() Description: ------------ I am trying to insert a line in a file after a line that is searched for. The line to insert is inserted fine, but the text after it gets truncated partially. ********* test.txt ************ PHP is a great language. It is a tool for the ages. It is easy to use and fast too! Test script: --------------- $absoluteFilePath = '<your_root_path>/test.txt'; $splFile = new \SplFileObject($absoluteFilePath, 'c+'); $splFile->flock(LOCK_EX); $splFile->rewind(); // Add to next line. while ($splFile->valid()) { $currentLine = $splFile->fgets(); if (strpos($currentLine, "It is a tool for the ages.") !== false) { $splFile->fwrite("But it has a few bugs.\n"); } } $splFile->flock(LOCK_UN); Expected result: ---------------- PHP is a great language. It is a tool for the ages. But it has a few bugs. It is easy to use and fast too! Actual result: -------------- PHP is a great language. It is a tool for the ages. But it has a few bugs. ast too! -- Edit bug report at https://bugs.php.net/bug.php?id=80088&edit=1 -- Fix committed: https://bugs.php.net/fix.php?id=80088&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=80088&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=80088&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=80088&r=needscript Try newer version: https://bugs.php.net/fix.php?id=80088&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=80088&r=support Expected behavior: https://bugs.php.net/fix.php?id=80088&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=80088&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=80088&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=80088&r=globals PHP version support discontinued: https://bugs.php.net/fix.php?id=80088&r=phptooold Daylight Savings: https://bugs.php.net/fix.php?id=80088&r=dst IIS Stability: https://bugs.php.net/fix.php?id=80088&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=80088&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=80088&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=80088&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=80088&r=mysqlcfg