composer: Platform check uses wrong PHP version on Windows

Hi! I’ve just been experimenting with the scripts options in composer.json and noticed that when running e.g. PHPUnit this way, I run into a PHP version mismatch: composer.phar is invoked with a specific PHP executab, usually from within PHPStorm but executes the script with the PHP found in PATH. After a bit of digging, i think the culprit is Symfony’s ExecutableFinder (called around here in EventDispatcher), which seems to guess the PHP from the environment variables exclusively, ignoring PHP_BINARY (which is available since PHP 5.4).

My composer.json:

{
	"name": "chillerlan/php-oauth-core",
	"description": "A PHP7.4+ OAuth client core library",
	"homepage": "https://github.com/chillerlan/php-oauth-core",
	"license": "MIT",
	"type": "library",
	"minimum-stability": "stable",
	"keywords": [
		"oauth", "oauth1", "oauth2", "authorization", "authentication",
		"client", "psr-7", "psr-17", "psr-18", "rfc5849", "rfc6749"
	],
	"authors": [
		{
			"name": "smiley",
			"email": "smiley@chillerlan.net",
			"homepage": "https://github.com/codemasher"
		}
	],
	"support": {
		"issues": "https://github.com/chillerlan/php-oauth-core/issues",
		"source": "https://github.com/chillerlan/php-oauth-core"
	},
	"provide": {
		"psr/http-client-implementation": "1.0"
	},
	"require": {
		"php": "^7.4 || ^8.0",
		"ext-curl":"*",
		"ext-json":"*",
		"ext-simplexml":"*",
		"ext-zlib": "*",
		"chillerlan/php-httpinterface": "^5.0",
		"psr/http-client":"^1.0",
		"psr/http-message": "^1.0",
		"psr/log": "^1.1 || ^2.0 || ^3.0"
	},
	"require-dev": {
		"phan/phan": "^5.2",
		"phpunit/phpunit": "^9.5"
	},
	"autoload": {
		"psr-4": {
			"chillerlan\\OAuth\\": "src/"
		}
	},
	"autoload-dev": {
		"psr-4": {
			"chillerlan\\OAuthTest\\": "tests/"
		}
	},
	"scripts": {
		"phpunit": "vendor/bin/phpunit",
		"phan": "vendor/bin/phan"
	},
	"config": {
		"lock": false,
		"sort-packages": true,
		"platform-check": true
	}
}

Output of composer diagnose:

Checking composer.json: OK
Checking platform settings: OK
Checking git settings: OK
Checking http connectivity to packagist: OK
Checking https connectivity to packagist: OK
Checking github.com rate limit: OK
Checking disk free space: OK
Checking pubkeys:
Tags Public Key Fingerprint: 57815BA2 7E54DC31 7ECC7CC5 573090D0  87719BA6 8F3BB723 4E5D42D0 84A14642
Dev Public Key Fingerprint: 4AC45767 E5EC2265 2F0C1167 CBBB8A2B  0C708369 153E328C AD90147D AFE50952
OK
Checking composer version: OK
Composer version: 2.1.12
PHP version: 7.4.3
PHP binary path: C:\amp\php\7.4.3\php.exe
OpenSSL version: OpenSSL 1.1.1d  10 Sep 2019
cURL version: 7.68.0 libz 1.2.11 ssl OpenSSL/1.1.1d
zip: extension present, unzip not available, 7-Zip present (7z)

When I run this command:

C:\php\8.0.0\php.exe C:/<project>/composer.phar run-script phpunit

I get the following output:

> vendor/bin/phpunit
PHP Fatal error:  Composer detected issues in your platform: Your Composer dependencies require a PHP version ">= 8.0.0". You are running 7.4.3. in <path>\vendor\composer\platform_check.php on line 33

And I expected this to happen:

I’d expect the script executed by run-script to use the same php executable that was used to invoke Composer (8.0.0 instead of 7.4.3 from PATH in this case).

Update: i added the @php to the script line, which seems to have it resolved. However i feel like this is a bit unintuitive.