memory usage increasing when using opcache.enable_cli and opcache.file_cache_only

Description

The below script using opcache.enable_cli=1 and opcache.file_cache_only=1 causes the PHP memory usage to continue to increase. If I disable file_cache_only, then the memory usage remains constant. I was able to reproduce in PHP 8.1, 8.2, and 7.4.

To reproduce, set-up scripts test.php and test2.php as listed below, create an empty directory /tmp/opcache, and then run:

php \
  -n \
  -d "zend_extension=opcache" \
  -d "opcache.enable_cli=1" \
  -d "opcache.file_cache=/tmp/opcache" \
  -d "opcache.file_cache_only=1" \
  test.php

When I run the above, the value of memory_get_usage() continues to increase. If I remove the line for "opcache.file_cache_only=1", then memory_get_usage() remains constant.

If it doesn't happen the 1st time, then try running it a 2nd time.

Can you please check why the memory usage continues to grow in this scenario?

Thanks for your help.

test.php:

<?php
for ($i = 0; $i < 10000; $i++)
{
	echo number_format(memory_get_usage())."\n";

	require('test2.php');
}

test2.php:

<?php
return;

PHP Version

PHP 8.1.11

Operating System

AlmaLinux 8

Start by running the supplied test.php and test2.php scripts with opcache.enable_cli=1 and opcache.file_cache_only=1, then compare memory_get_usage() with file_cache_only disabled. Investigate the PHP opcache file-cache path involved in repeated test2.php requirements; done means the reported growth is explained and the reproduction no longer shows increasing memory.