You cannot use the "Symfony\Component\HttpClient\Psr18Client" as the "psr/http-client" package is not installed

[brettmc]

PHP version: 8.2.0

Description
php-http/discovery plugin installs a psr18 client that cannot be discovered

How to reproduce
composer.json:

{
  "config": {
    "allow-plugins": {
      "php-http/discovery": true
    }
  },
  "require": {
    "php-http/client-implementation": "^1.0",
    "php-http/discovery": "^1.18"
  }
}

test.php:

<?php
require 'vendor/autoload.php';
$client = \Http\Discovery\Psr18ClientDiscovery::find();
var_dump(get_class($client));

composer update
php test.php

Results:

Fatal error: Uncaught LogicException: You cannot use the "Symfony\Component\HttpClient\Psr18Client" as the "psr/http-client" package is not installed. Try running "composer require php-http/discovery psr/http-client-implementation:*". in /usr/src/myapp/vendor/symfony/http-client/Psr18Client.php on line 37

Possible Solution
As a workaround, I could require psr/http-client, but we don't directly require or use it.

[dbu]

ok, took me a moment but i think this is a confusion between the psr client and the legacy php-http client abstraction.

if you want psr-18, you don't need to require php-http/client-implementation but psr/http-client-implementation

[dbu]

if you manually require psr/http-client, it will only work by chance because the symfony http client has adapters for both http client interfaces.

[brettmc]

Changing my requirements to use psr/http-client-implementation gives the same error:

{
  "config": {
    "allow-plugins": {
      "php-http/discovery": true
    }
  },
  "require": {
    "psr/http-client-implementation": "*",
    "php-http/discovery": "^1.18"
  }
}

But, I was mistaken earlier when I said we did not directly rely on psr/http-client - we do, and so I should add that dependency to our library.

I'd like to understand better about "it will only work by chance" though, I'd much prefer it to work on purpose! :)

[dbu]

php-http/client-implementation is the virtual package for the httplug interfaces by php-http. after we built that, we proposed psr-18, which is now accepted and defines an "official" http client interface. the virtual package for psr18 is psr/http-client-implementation.

we did not deprecate httplug because it also provides an asynchronous client, and psr-18 is only about synchronous http requests.

symfony/http-client provides both an integration with psr18 and with the legacy php-http client - this is why i said it would work by chance if you requries a php-http client implementation but then expect to find a psr18 client.

all that said, i just ran your minimal composer.json and indeed psr/http-client is not installed automatically. i think this is indeed a mistake of discovery. i think #249 would be the fix. can you try with that branch if your project then indeed works?

[brettmc]

Confirmed as working using dev-composer-plugin branch. I get psr/http-client, and discovery works as expected.

[dbu]

should be fixed in https://github.com/php-http/discovery/releases/tag/1.19.0