Finding executing script path in CLI impossible for relative filepaths after chdir - SCRIPT_FILENAME should be the absolute path in CLI too

Description

The following code:

mkdir -p /abc/def
mkdir -p /abc/xyz
cd /abc/def
php ../xyz/bar.php

/abc/xyz/bar.php

<?php
var_dump( realpath( filter_input( INPUT_SERVER, 'SCRIPT_FILENAME' ) ) );
chdir( '/tmp' );
var_dump( realpath( filter_input( INPUT_SERVER, 'SCRIPT_FILENAME' ) ) );

Resulted in this output:

string(16) "/abc/xyz/bar.php"
bool(false)

SCRIPT_FILENAME is supposed to be the

The absolute pathname of the currently executing script.

while SCRIPT_NAME is the passed path (or the path relative to DOCUMENT_ROOT ?)
https://www.php.net/manual/en/reserved.variables.server.php

The docs mention:

If a script is executed with the CLI, as a relative path, such as file.php or ../file.php, $_SERVER['SCRIPT_FILENAME'] will contain the relative path specified by the user.

Isn't this a bug? Bc it states it should be an absolute path, and it's obviously not. Which means the 2 are identical in CLI.

Which leads back to my original example:
due to this inconsistency, it's impossible to find the currently executing script's path in CLI, if the path passed to PHP isn't absolute and chdir() is called anywhere in the application.
This makes finding the source of a bug from an error trace almost impossible, if there are multiple directories with this file

PHP Version

8.4

Operating System

No response

まず、PHP 8.4 で相対パスの CLI 例を再現し、CLI エントリーポイントが SCRIPT_FILENAME をどのように設定するかを調べます。chdir('/tmp'); の前後で動作を確認します。相対パスで呼び出したときに SCRIPT_FILENAME が実行中のスクリプトの絶対パスのままであれば完了です。