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KO Headers Sent Diagnostic

Logs the first PHP file and line that sent output before WordPress could send headers.

by KO · github.com/wy4tt34rp/ko-headers-sent-diagnostic

★ 0stars

Install

Download source zip No release zip yet

This is the repository archive. It installs, but the folder name will carry the branch suffix and updates will not flow.

Install straight from GitHub with WP-CLI:

wp plugin install https://github.com/wy4tt34rp/ko-headers-sent-diagnostic/archive/refs/heads/main.zip
No built-in updater. New versions won't appear under Dashboard → Updates. Install new releases yourself, or let Git Updater track the repository.
Readme github.com/wy4tt34rp/ko-headers-sent-diagnostic ↗

DEX early-output diagnostic

The DEX login response currently begins with two line-feed bytes before the <!DOCTYPE html> declaration. That makes PHP report that headers have already been sent, preventing WordPress from setting its login test cookie.

Install

  1. Ensure wp-content/mu-plugins/ exists on the DEX development site.
  2. Upload ko-headers-sent-diagnostic.php directly into that directory. It must be directly inside mu-plugins, not inside another folder.
  3. Request https://dex.dev.velaagency.com/wp-login.php once.
  4. Download wp-content/ko-headers-sent-diagnostic.log.

The log entry will resemble:

[KO headers diagnostic] Early output detected during plugins_loaded. Output started at /path/to/wp-content/plugins/example/example.php:123

The reported file and line identify where the first output began. Common fixes are removing bytes before <?php, removing a trailing ?> and its whitespace, saving the file as UTF-8 without BOM, or removing accidental debug output.

Remove

Delete wp-content/mu-plugins/ko-headers-sent-diagnostic.php and wp-content/ko-headers-sent-diagnostic.log after correcting the source file.