SolverProblemsException

[enumag]

My composer.json:

{
    "require": {
        "amphp/file": "^1.0@dev",
        "amphp/http-client": "^4.2"
    },
    "require-dev": {
        "psr/log": "*"
    }
}

Output of composer diagnose:

Checking composer.json: WARNING
No license specified, it is recommended to do so. For closed-source software you may use "proprietary" as license.
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: 1.10.5
PHP version: 7.4.4
PHP binary path: /usr/bin/php7.4
OpenSSL version: OpenSSL 1.1.1d  10 Sep 2019

When I run this command:

composer up

I get the following output:

  [Composer\DependencyResolver\SolverProblemsException]                        
  Problem 1                                                                    
      - Installation request for amphp/file ^1.0@dev -> satisfiable by amphp/file[1.x-dev].                                                               
      - amphp/http-client v4.2.2 conflicts with amphp/file[dev-master].        
      - remove amphp/file 1.x-dev|keep amphp/file dev-master                   
      - Installation request for amphp/http-client ^4.2 -> satisfiable by amphp/http-client[v4.2.2].   

And I expected this to happen:

Successful installation.

---

Additional notes:

The peculiar thing is that this composer.json actually works fine:

{
    "require": {
        "amphp/file": "^1.0@dev",
        "amphp/http-client": "^4.2"
    }
}

But as soon as I add anything (even a package completely unrelated to these two) into require-dev, it breaks with the exception above.

I think that the bug is somehow caused by this conflict in amphp/http-client. As you can see http-client has a conflict with amphp/file >=2 - which doesn't exist ofc, here is the reasoning behind the conflict. But aside from blocking nonexistent 2.x, the conflict also blocks amphp/file dev-master. This is not intentional however so there is a branch-alias in place to specify that master is 1.x which should make the installation pass. Which it does, but only when require-dev it empty.

[kelunik]

I can reproduce the exact behavior and also believe this is a bug in the solver rather than a wrong dependency / conflict specification in the mentioned packages.

Works fine with Composer version 2.0-dev (2.0-dev+56811b4c8fec9c2eda5bd47a2c079e121c668eb4), but fails with 1.10.1.

[Seldaek]

That's a bug we fixed in 2.0 indeed. The fact that a conflict on >=x matches dev-master. It's not fixable in 1.x sorry.