Custom Installer and moving (temporary?) files from vcs repositories within vendor/

[garvinhicking]

Hi!

I'm creating my own custom installer. I have multiple helper composer packages that contain skeleton files that I can merge into a composer project. These skeleton files are scattered throughout a project (i.e. in /htdocs, /.ddev, /build etc.).

My idea was to make each composer package define a set of "move rules" within their respective composer.json files, i.e.:

extra: {
  moveFiles: {
    "build": "/build",
    "docs": "/assets/docs/"
  }
}

My custom installer would then iterate this moveFiles structure and move each entry from vendor/myVendor/myPackage/XXX to (root)/YYY.

That worked flawlessly when I had my packages inside the repository as a simple path mapping. Now that I put each composer packages into a private github repository and I do the process, my custom installer cannot find the original source files.

I debugged this happens because within the LibraryInstaller inside the install/update method, at this point in the code the files are not yet moved into vendor/myVendor/myPackage/XXX but instead the files live in a directory like vendor/composer/a4f4780b/myVendor-myPackage-0d2c7734d9378c7e3ed14ad760dd7e3b42b94e5a/XXX.

How would I make my custom installer know this actual directory location? I cannot seem to find any API method like $package->getTemporaryInstallPath() or something like it.

I do know that https://github.com/composer/installers/blob/main/src/Composer/Installers/BaseInstaller.php uses $locations to map the full install paths of a composer package. My special use case though is that files within a composer package go to different places, and most importantly - I want to be able that the custom installer detects if any placed files have been manually modified (through magic comments) and only overwrite files in case file is not maintained manually. So I'd defintely have to iterate files at this point, and not the whole package.

So my hope is that actually I can get a packages' temporary location at the time where LibraryInstaller::install or LibraryInstaller::update is executed.

(I only worked with custom composer installers for the better of a day, so please excuse me if I missed a thing. Sadly the docs in https://getcomposer.org/doc/articles/custom-installers.md are rather brief and missing actual examples. If anyone can point me into a direction, I'd love to help improving the documentation for this!)

Best regards,
Garvin

[garvinhicking]

OK, so I had to take a deep dive into promises. I found my mistake.

I implemented the install/update methods like this:

    public function update(InstalledRepositoryInterface $repo, PackageInterface $initial, PackageInterface $target)
    {
        $return = parent::update($repo, $initial, $target);
        return $this->unpackage($repo, $target, $return);
    }

    public function install(InstalledRepositoryInterface $repo, PackageInterface $package)
    {
        $return = parent::install($repo, $package);
        return $this->unpackage($repo, $package, $return);
    }

which is pretty wrong of course; my unpackage() method passed on the $return value of the parent method, but it seems the code contained in said return promise was not executed. So I figured the correct way would need to be:

    public function update(InstalledRepositoryInterface $repo, PackageInterface $initial, PackageInterface $target)
    {
        return parent::update($repo, $initial, $target)->then(function () use ($repo, $initial, $target) {
            $this->unpackage($repo, $target);
        });

    }

    public function install(InstalledRepositoryInterface $repo, PackageInterface $package)
    {
        return parent::install($repo, $package)->then(function () use ($repo, $package) {
            $this->unpackage($repo, $package);
        });
    }

So first the parent method is called, and append to its promise, my custom unpackaging script gets called.

Regards,
Garvin