Bug #79718 [Opn]: header_register_callback behaves differently for requests with no output

Edit report at https://bugs.php.net/bug.php?id=79718&edit=1 ID: 79718 Updated by: requinix@php.net Reported by: brianlmoon@php.net Summary: header_register_callback behaves differently for requests with no output Status: Open Type: Bug Package: Output Control Operating System: Linux PHP Version: 7.4.7 Block user comment: N Private report: N New Comment: Given that the callback is running when output is being flushed after script execution and when autoloading is no longer available (?), this makes sense. If there is output then what that means is you started output while the script was still running and thus autoloading was available. Which leads to an easy solution: have your script flush at the end. After all, shutdown callbacks happen when the engine is in the process of shutting down, so it's hard to know exactly what capabilities will still be available. Previous Comments: ------------------------------------------------------------------------ [2020-06-19 17:48:37] brianlmoon@php.net Description: ------------ When a request has no output (a redirect or 204 no content for example), or the request method is HEAD (even if the request would have generated output normally), autoloading inside the callback provided to header_register_callback fails. For requests with output, autoloading works as expected. Test script: --------------- <?php error_reporting(-1); ini_set("display_errors", true); header("Location: /foo"); header("X-Bar: 2"); spl_autoload_register(function($class) { include __DIR__."/Foo.php"; }); header_register_callback(function() { header("X-Baz: 3"); header("X-Foo: ".Foo::BAR); }); if(!empty($_GET["output"])) { echo "test"; } /* Foo.php <?php class Foo { const BAR = 1; } */ Expected result: ---------------- The following headers are returned for all requests regardless if there is output or not. X-Bar: 2 X-Baz: 3 X-Foo: 1 For example, with output: < HTTP/1.1 302 Found < Server: nginx/1.17.10 < Date: Fri, 19 Jun 2020 17:45:39 GMT < Content-Type: text/html; charset=UTF-8 < Transfer-Encoding: chunked < Connection: keep-alive < Location: /foo < X-Bar: 2 < X-Baz: 3 < X-Foo: 1 < Strict-Transport-Security: max-age=31536000; includeSubdomains < * Connection #0 to host labs.moonspot.net left intact test Actual result: -------------- < HTTP/1.1 302 Found < Server: nginx/1.17.10 < Date: Fri, 19 Jun 2020 17:46:28 GMT < Content-Type: text/html; charset=UTF-8 < Transfer-Encoding: chunked < Connection: keep-alive < Location: /foo < X-Bar: 2 < X-Baz: 3 < Strict-Transport-Security: max-age=31536000; includeSubdomains < <br /> <b>Fatal error</b>: Uncaught Error: Class 'Foo' not found in /xxx/public/test.php:16 Stack trace: #0 [internal function]: {closure}() #1 {main} thrown in <b>/xxx/public/test.php</b> on line <b>16</b><br /> ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=79718&edit=1