Req #77758 [NEW]: Warning: headers already sent should identify what triggered the send

From: webmaster at jamescobban dot net Operating system: linux PHP version: 7.2.16 Package: Apache2 related Bug Type: Feature/Change Request Bug description:Warning: headers already sent should identify what triggered the send Description: ------------ The message Warning: Cannot modify header information - headers already sent is one of the big time-wasters of our profession. All of the documentation on this message including hundreds of web-pages and forum discussions end up as just a long list of things that the program MIGHT have done that would cause this message to appear. There is no documentation of exactly how a programmer should go about identifying exactly what the, usually trivial, mistake was that triggered the early send of the headers. The message should include information that directly points at the program action that caused PHP to send the headers. Test script: --------------- print ''; // empty string header("Content-Type: application/json"); Expected result: ---------------- Warning: Cannot modify header information - headers already sent because of backtrace to line 1. Actual result: -------------- Warning: Cannot modify header information - headers already sent at line 2. -- Edit bug report at https://bugs.php.net/bug.php?id=77758&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=77758&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=77758&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=77758&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=77758&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=77758&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=77758&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=77758&r=needscript Try newer version: https://bugs.php.net/fix.php?id=77758&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=77758&r=support Expected behavior: https://bugs.php.net/fix.php?id=77758&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=77758&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=77758&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=77758&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=77758&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=77758&r=dst IIS Stability: https://bugs.php.net/fix.php?id=77758&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=77758&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=77758&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=77758&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=77758&r=mysqlcfg