Logs wrapped with newlines even when output decoration is disabled

Description

When decorate_workers_output is disabled as a pool directive, and worker output is redirected to the main error log:

decorate_workers_output = no
catch_workers_output = yes

And error log is enabled in global php-fpm.conf:

error_log = /var/log/php8.3-fpm.log

When the following code is executed in an FPM worker:

$err = array_fill(0, 128, "banana");
file_put_contents("php://stderr", json_encode($err));

error_log contains this:

["banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","bana
na","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana"]

But I expected the logged contents to be this instead:

["banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana","banana"]

Links:

• https://github.com/php/php-src/blob/PHP-8.3.2/sapi/fpm/fpm/fpm_stdio.c#L196-L197
• https://pracucci.com/php-on-kubernetes-application-logging-via-unix-pipe.html

PHP Version

PHP 8.3.2

Operating System

No response