Reproduce:

= PHP version: ======

$ php -v
PHP 7.1.16-1+ubuntu16.04.1+deb.sury.org+1 (cli) (built: Apr 5 2018 08:47:00) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.1.0, Copyright (c) 1998-2018 Zend Technologies
with Zend OPcache v7.1.16-1+ubuntu16.04.1+deb.sury.org+1, Copyright (c) 1999-2018, by Zend Technologies

= direct composer latest version (2.2.4) works ok: ===========
$ curl -Ns https://getcomposer.org/download/2.2.4/composer.phar > ./composer.phar && chmod 777 ./composer.phar && ./composer.phar -V
Composer version 2.2.4 2022-01-08 12:30:42

= "latest" composer version download fetches composer which causes this error on use (current latest is 2.2.4): ===========
$ curl -Ns https://getcomposer.org/composer.phar > ./composer.phar && chmod 777 ./composer.phar && ./composer.phar -V
PHP Fatal error: Uncaught Error: Call to undefined function Symfony\Component\Console\Output\stream_isatty() in phar:///home/palmam/composer.phar/vendor/symfony/console/Output/StreamOutput.php:113
Stack trace:
#0 phar:///home/palmam/composer.phar/vendor/symfony/console/Output/StreamOutput.php(51): Symfony\Component\Console\Output\StreamOutput->hasColorSupport()
#1 phar:///home/palmam/composer.phar/vendor/symfony/console/Output/ConsoleOutput.php(42): Symfony\Component\Console\Output\StreamOutput->__construct(Resource id #99, 32, NULL, Object(Symfony\Component\Console\Formatter\OutputFormatter))
#2 phar:///home/palmam/composer.phar/src/Composer/Factory.php(287): Symfony\Component\Console\Output\ConsoleOutput->__construct(32, NULL, Object(Symfony\Component\Console\Formatter\OutputFormatter))
#3 phar:///home/palmam/composer.phar/src/Composer/Console/Application.php(125): Composer\Factory::createOutput()
#4 phar:///home/palmam/composer.phar/bin/composer(83): Composer\Console\Application->run()
#5 /home/palmam/composer.phar(30): re in phar:///home/palmam/composer.phar/vendor/symfony/console/Output/StreamOutput.php on line 113

Fatal error: Uncaught Error: Call to undefined function Symfony\Component\Console\Output\stream_isatty() in phar:///home/palmam/composer.phar/vendor/symfony/console/Output/StreamOutput.php:113
Stack trace:
#0 phar:///home/palmam/composer.phar/vendor/symfony/console/Output/StreamOutput.php(51): Symfony\Component\Console\Output\StreamOutput->hasColorSupport()
#1 phar:///home/palmam/composer.phar/vendor/symfony/console/Output/ConsoleOutput.php(42): Symfony\Component\Console\Output\StreamOutput->__construct(Resource id #99, 32, NULL, Object(Symfony\Component\Console\Formatter\OutputFormatter))
#2 phar:///home/palmam/composer.phar/src/Composer/Factory.php(287): Symfony\Component\Console\Output\ConsoleOutput->__construct(32, NULL, Object(Symfony\Component\Console\Formatter\OutputFormatter))
#3 phar:///home/palmam/composer.phar/src/Composer/Console/Application.php(125): Composer\Factory::createOutput()
#4 phar:///home/palmam/composer.phar/bin/composer(83): Composer\Console\Application->run()
#5 /home/palmam/composer.phar(30): re in phar:///home/palmam/composer.phar/vendor/symfony/console/Output/StreamOutput.php on line 113