README

SuperKernel Metadata

super-kernel/metadata restores the package metadata that skernel build generates for a project: the root and installed packages, their environment requirements, and their class maps, so an application starts without parsing Composer files or scanning sources.

Installation

composer require super-kernel/metadata

The package needs a project installed with Composer, whose vendor/autoload.php loads it. The metadata it restores exists only after skernel build has run in the project.

What it provides

The vendor directory of the Composer class loader that loads the package, also after the project moves and inside a Phar.
The project directory recorded by the build.
The root and installed packages with their versions, references, Composer types, and environment requirements.
The package that owns a class, and the class map of each package.
Detection of metadata that is missing, damaged, or older than the project's composer.lock.
The publisher that skernel build calls to write the metadata.

It does not:

parse composer.json or composer.lock, or scan class files;
register an autoloader or include Composer files autoloads; vendor/autoload.php keeps doing that;
rebuild outdated metadata; skernel build does.

Quick start

Any class of the project serves to look up its package. Save one as src/Billing/Invoice.php:

<?php

declare(strict_types=1);

namespace Src\Billing;

final class Invoice
{
}

Restore the metadata and ask who owns which class. Save the script as bin/packages.php:

<?php

declare(strict_types=1);

use Src\Billing\Invoice;
use SuperKernel\Metadata\Provider\BasePathProvider;
use SuperKernel\Metadata\Provider\PackageManagerProvider;
use SuperKernel\Metadata\Provider\VendorDirProvider;

require dirname(__DIR__) . '/vendor/autoload.php';

$vendorDir = new VendorDirProvider()();
$basePath = new BasePathProvider()($vendorDir);
$packages = new PackageManagerProvider()($vendorDir, $basePath);

echo $packages->packageForClass(VendorDirProvider::class)?->name(), PHP_EOL;
echo $packages->root()->composerType(), PHP_EOL;
var_dump($packages->packageForClass(Invoice::class) === $packages->root());
var_dump($packages->root()->locatedPath() === (string) $basePath);

Build the project and run the script:

skernel build
php bin/packages.php

It prints:

super-kernel/metadata
project
bool(true)
bool(true)

Public surface

Name	Kind	Purpose
`SuperKernel\Metadata\Provider\VendorDirProvider`	Class	Supplies `VendorDirInterface`: the vendor directory of the Composer class loader that loads this package.
`SuperKernel\Contract\VendorDirInterface`	Interface	The vendor directory; casting it to a string gives the path.
`SuperKernel\Metadata\Provider\BasePathProvider`	Class	Supplies `BasePathInterface`: the project directory recorded by the build.
`SuperKernel\Contract\BasePathInterface`	Interface	The project directory; casting it to a string gives the path.
`SuperKernel\Metadata\Provider\PackageManagerProvider`	Class	Supplies `PackageManagerInterface`, restored from the generated metadata.
`SuperKernel\Contract\PackageManagerInterface`	Interface	Lists the packages and finds a package by name, by Composer type, or by one of its classes.
`SuperKernel\Contract\PackageMetadataInterface`	Interface	One package: name, version, reference, and located path.
`SuperKernel\Contract\EnvironmentRequirementInterface`	Interface	One requirement on a Composer platform package, such as PHP or an extension, with the package that declares it.
`SuperKernel\Metadata\Build\MetadataPublisher`	Class	Writes the metadata; `skernel build` calls it in the project's own process.
`SuperKernel\Metadata\Constants\Protocol`	Class	`VERSION` is the build protocol this version reads and writes.

Behavior to know

Run skernel build after composer install or composer update and after changing autoload rules or annotated classes, or start with skernel run, which builds first. Switching between composer install and composer install --no-dev without a change to composer.lock is not detected; build again after switching.
PackageManagerProvider and BasePathProvider raise SuperKernel\Metadata\Exception\BuildRequiredException when the metadata is missing or invalid, was written under another build protocol, or does not match the current composer.lock. Its message names the problem and ends with Run `skernel build` to generate the project metadata.
VendorDirProvider raises SuperKernel\Metadata\Exception\MetadataException with the message No registered Composer class loader serves super-kernel/metadata. when no Composer class loader loads the package.
Every provider call returns a new value; a SuperKernel container keeps one instance of each.
A project whose vendor directory lies inside it can move with its vendor directory, and the metadata stays valid.

Documentation

The developer documentation describes every lookup with complete examples, the generated files and how to ship them, publishing metadata, and the errors and their messages: SuperKernel Metadata.

License

Released under the MIT License. See LICENSE.

super-kernel / metadata

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