cweagans\Composer\Patches::postInstall PHP Method

    public function postInstall(PackageEvent $event)
    {
        // Get the package object for the current operation.
        $operation = $event->getOperation();
        /** @var PackageInterface $package */
        $package = $this->getPackageFromOperation($operation);
        $package_name = $package->getName();
        if (!isset($this->patches[$package_name])) {
            if ($this->io->isVerbose()) {
                $this->io->write('<info>No patches found for ' . $package_name . '.</info>');
            }
            return;
        }
        $this->io->write('  - Applying patches for <info>' . $package_name . '</info>');
        // Get the install path from the package object.
        $manager = $event->getComposer()->getInstallationManager();
        $install_path = $manager->getInstaller($package->getType())->getInstallPath($package);
        // Set up a downloader.
        $downloader = new RemoteFilesystem($this->io, $this->composer->getConfig());
        // Track applied patches in the package info in installed.json
        $localRepository = $this->composer->getRepositoryManager()->getLocalRepository();
        $localPackage = $localRepository->findPackage($package_name, $package->getVersion());
        $extra = $localPackage->getExtra();
        $extra['patches_applied'] = array();
        foreach ($this->patches[$package_name] as $description => $url) {
            $this->io->write('    <info>' . $url . '</info> (<comment>' . $description . '</comment>)');
            try {
                $this->eventDispatcher->dispatch(NULL, new PatchEvent(PatchEvents::PRE_PATCH_APPLY, $package, $url, $description));
                $this->getAndApplyPatch($downloader, $install_path, $url);
                $this->eventDispatcher->dispatch(NULL, new PatchEvent(PatchEvents::POST_PATCH_APPLY, $package, $url, $description));
                $extra['patches_applied'][$description] = $url;
            } catch (\Exception $e) {
                $this->io->write('   <error>Could not apply patch! Skipping. The error was: ' . $e->getMessage() . '</error>');
                if (getenv('COMPOSER_EXIT_ON_PATCH_FAILURE')) {
                    throw new \Exception("Cannot apply patch {$description} ({$url})!");
                }
            }
        }
        $localPackage->setExtra($extra);
        $this->io->write('');
        $this->writePatchReport($this->patches[$package_name], $install_path);
    }