[mpeshev]

wp-cron.php finishes the response with fastcgi_finish_request() or litespeed_finish_request() before loading WordPress ([44488]). On a subdomain network, a request for a site that does not exist then reaches the redirect in ms-settings.php after the headers were sent, and every such request logs "Cannot modify header information - headers already sent". This only sends the redirect header when headers have not been sent; the request still ends at the same point.

The ticket suggests sending that case to ms_not_installed() instead. For front-end requests that calls dead_db(), which runs a db-error.php drop-in or reports a database error for a site that simply does not exist, so this keeps the existing quiet exit.

Trac ticket: https://core.trac.wordpress.org/ticket/53244

Testing

No PHPUnit test: the code runs during the multisite bootstrap, sends a header and exits. Reproduced instead with PHP-FPM 8.3 and FastCGI requests on a throwaway subdomain network running trunk:

• GET nosuchsite.<network>/wp-cron.php?doing_wp_cron=1: without the patch, PHP Warning: Cannot modify header information - headers already sent in .../ms-settings.php on line 84; with it, no warning.
• GET nosuchsite.<network>/wp-login.php still returns 302 Location: http://<network>/wp-signup.php?new=nosuchsite.
• wp-cron.php on the existing main site runs without warnings.

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Claude Opus 5.5
Used for: reproducing the warning on PHP-FPM, drafting the fix, and running the checks above. I reviewed every line.

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