[dev] Add support for symlinking to the root project during local dev…

…elopment. Disabled by default as it's not recommended.

See composer/composer#5974 and composer/composer#6174

example/project/README.md

@@ -3,3 +3,12 @@
 Demo root project integrating with Drupal libraries installer.
 
 Update locally after committing by running `composer update zodiacmedia/drupal-libraries-installer`.
+
+Or symlink to a copy of the current root project with:
+
+```bash
+# Enable "symlink-root-project" mode (--json requires composer 2).
+composer config --json extra.symlink-root-project true
+# Apply the symlink.
+composer update --lock
+```

example/project/composer.json

@@ -26,13 +26,38 @@
         "zodiacmedia/drupal-libraries-installer": "*@dev",
         "zodiacmedia/drupal-libraries-installer-demo-dependency": "*@dev"
     },
+    "require-dev": {
+        "composer/composer": "^1.10"
+    },
+    "autoload": {
+        "classmap": [
+            "scripts/composer/ScriptHandler.php"
+        ]
+    },
+    "scripts": {
+        "preSymlinkMainProject": "ExampleDrupalLibrariesProject\\composer\\ScriptHandler::preInstall",
+        "symlinkMainProject": "ExampleDrupalLibrariesProject\\composer\\ScriptHandler::postInstall",
+        "pre-install-cmd": [
+            "@preSymlinkMainProject"
+        ],
+        "pre-update-cmd": [
+            "@preSymlinkMainProject"
+        ],
+        "post-install-cmd": [
+            "@symlinkMainProject"
+        ],
+        "post-update-cmd": [
+            "@symlinkMainProject"
+        ]
+    },
     "config": {
         "preferred-install": "source",
         "classmap-authoritative": true,
         "prepend-autoloader": false,
         "optimize-autoloader": true
     },
     "extra": {
+        "symlink-root-project": false,
         "installer-paths": {
             "web/libraries/ckeditor/{$name}": [
                 "vendor:drupal-library_ckeditor"

example/project/scripts/composer/ScriptHandler.php

@@ -0,0 +1,128 @@
+<?php
+
+namespace ExampleDrupalLibrariesProject\composer;
+
+use Composer\Script\Event;
+use Composer\Util\Filesystem;
+use Composer\Util\Platform;
+
+/**
+ * The drupal-libraries-installer example project script handler.
+ *
+ * Attempts to symlink to the parent repository during development when
+ * "extra.symlink-root-project" is true.
+ *
+ * Mainly useful for testing certain behaviours without having to duplicate
+ * code or commit every time in order for composer to pull it in.
+ *
+ * Composer restricts symlinking to a path containing the current project.
+ * So we have to handle it manually with some hacky code.
+ *
+ * It's definitely not adviced as you could accidentally discard changes in
+ * your root project during an install/update if the appropriate event hooks
+ * are not triggered.
+ */
+class ScriptHandler {
+
+  protected const PACKAGE_NAME = 'zodiacmedia/drupal-libraries-installer';
+
+  /**
+   * Attempt to prepare for the post install/update.
+   *
+   * @param \Composer\Script\Event $event
+   *   The composer event.
+   */
+  public static function preInstall(Event $event) {
+    $composer = $event->getComposer();
+    $root_package = $composer->getPackage();
+    $locker = $composer->getLocker();
+    // Always attempt to clean up if:
+    // - the lock file is not present.
+    // - the lock file is outdated.
+    // - in the pre-update hook.
+    $originating_event = $event->getOriginatingEvent();
+    $originating_event_name = $originating_event ? $originating_event->getName() : NULL;
+    $needs_updating = $originating_event_name === 'pre-update-cmd' || !$locker->isLocked() || !$locker->isFresh();
+    $should_symlink = empty($root_package->getExtra()['symlink-root-project']);
+    if ($needs_updating || $should_symlink) {
+      // Don't symlink the root project. Attempt to remove any existing symlink.
+      $filesystem = new Filesystem();
+      $destination = static::getPackageDestination();
+      $destination = $filesystem->normalizePath($destination);
+
+      $is_junction = $filesystem->isJunction($destination);
+      $is_symlink = is_link($destination);
+      if ($is_junction || $is_symlink) {
+        $io = $event->getIO();
+        if ($is_junction) {
+          $io->writeError(sprintf('Removing existing junction for <info>%s</info>', static::PACKAGE_NAME));
+        }
+        elseif ($is_symlink) {
+          $io->writeError(sprintf('Removing existing symlink for <info>%s</info>', static::PACKAGE_NAME));
+        }
+        $filesystem->removeDirectory($destination);
+      }
+    }
+  }
+
+  /**
+   * Attempt to symlink to the parent repository during development.
+   *
+   * @param \Composer\Script\Event $event
+   *   The composer event.
+   */
+  public static function postInstall(Event $event) {
+    $root_package = $event->getComposer()->getPackage();
+    if (empty($root_package->getExtra()['symlink-root-project'])) {
+      // Do nothing.
+      return;
+    }
+
+    $io = $event->getIO();
+    $filesystem = new Filesystem();
+    $link = implode(DIRECTORY_SEPARATOR, ['..', '..', '..', '..']);
+    $destination = static::getPackageDestination();
+    $destination = $filesystem->normalizePath($destination);
+    if (Platform::isWindows()) {
+      if (!$filesystem->isJunction($destination)) {
+        $io->writeError(sprintf('Creating junction for <info>%s</info>', static::PACKAGE_NAME));
+        $filesystem->removeDirectory($destination);
+        $filesystem->junction($link, $destination);
+      }
+    }
+    else {
+      if (!$filesystem->isSymlinkedDirectory($destination)) {
+        $io->writeError(sprintf('Creating symlink for <info>%s</info>', static::PACKAGE_NAME));
+        // Attempt to remove the existing directory.
+        $filesystem->removeDirectory($destination);
+        if (!static::createSymlink($link, $destination)) {
+          throw new \RuntimeException(sprintf('Failed to create a symlink for "%s"', static::PACKAGE_NAME));
+        }
+      }
+    }
+  }
+
+  /**
+   * Returns the destination package directory.
+   */
+  protected static function getPackageDestination() {
+    return implode(DIRECTORY_SEPARATOR, [
+      getcwd(),
+      'vendor',
+      'zodiacmedia',
+      'drupal-libraries-installer',
+    ]);
+  }
+
+  /**
+   * Creates a symlink to the root project.
+   */
+  protected static function createSymlink($target, $link) {
+    if (!function_exists('symlink')) {
+      return FALSE;
+    }
+
+    return @symlink($target, $link);
+  }
+
+}