[php-fpm][error_log] the log always has prefix "NOTICE: PHP message:"

[mocxi]

Hello,

I'm using docker image php:8.4-fpm with fpm pool setting as below:

access.log = /proc/self/fd/1
catch_workers_output = yes
decorate_workers_output = no
php_flag[display_errors] = off
php_admin_value[error_log] = /proc/self/fd/2
php_admin_flag[log_errors] = off

when I tri to print error_log in php:

error_log('test');

I see that php-fpm process added prefix to the log:

NOTICE: PHP message: test

(Note: Setting decorate_workers_output = no successfully removes timestamps/FPM headers from stdout/stderr, but does not affect the specific prefix added by error_log() redirected to /proc/self/fd/2)

Is there a specific PHP-FPM pool configuration directive, or perhaps a different approach (other than switching to file_put_contents('php://stderr', ...)), that can completely suppress the NOTICE: PHP message: prefix when error_log() output is redirected to /proc/self/fd/2?

[tianon]

Unfortunately, as far as I can tell, that prefix is hard-coded directly in the source: https://github.com/php/php-src/blob/e97c0dc340be7387498b92b182b9356b960a3bd0/sapi/fpm/fpm/fpm_main.c#L631