[dev] Monorepo: PSR-4 autoloader for local dev-environment (#52331)

In this PR we introduce dev-only SPR-4 autoloader, so newly introduced PHP classes are available without dumping autoload (specific the core autoloader).

packages/php/monorepo-plugin/autoload-dev.php

@@ -0,0 +1,35 @@
+<?php declare( strict_types=1 );
+
+( function() {
+	// Ensure we are hooking up after primary autoloading being available.
+	if ( class_exists( \Automattic\WooCommerce\Autoloader::class, false ) ) {
+		// Locate the reference point first - WooCommerce autoloader in our case.
+		$reference_point = ( new \ReflectionClass( \Automattic\WooCommerce\Autoloader::class ) )->getFileName();
+		$plugin_path     = dirname( $reference_point, 2 );
+
+		// Load composer manifest for class mapping (we'll pick PRS4 only, as it's where new classes are introduced).
+		static $namespaces = [];
+		$declarations      = json_decode( file_get_contents( $plugin_path . DIRECTORY_SEPARATOR . 'composer.json' ), true );
+		foreach ( $declarations['autoload']['psr-4'] ?? [] as $namespace => $path ) {
+			$namespaces[$namespace] = $plugin_path . DIRECTORY_SEPARATOR . $path;
+		}
+		foreach ( $declarations['autoload-dev']['psr-4'] ?? [] as $namespace => $path ) {
+			$namespaces[$namespace] = $plugin_path . DIRECTORY_SEPARATOR . $path;
+		}
+
+		// Follow the provided mapping and require the matching file if found it.
+		spl_autoload_register( function ( string $class ) use( $namespaces ): bool {
+			foreach ( $namespaces as $namespace => $path ) {
+				if ( strpos( $class, $namespace ) === 0 ) {
+					$file = $path . str_replace( "\\", DIRECTORY_SEPARATOR, str_replace( $namespace, '', $class ) . '.php' );
+					if ( file_exists( $file ) ) {
+						require_once $file;
+						return true;
+					}
+				}
+			}
+			return false;
+		} );
+	}
+} )();
+

packages/php/monorepo-plugin/src/Plugin.php

@@ -69,6 +69,7 @@ class Plugin implements PluginInterface, EventSubscriberInterface {
 		return array(
 			// Make sure this event will run after the Jetpack Autoloader plugin.
 			ScriptEvents::POST_AUTOLOAD_DUMP => array( 'onPostAutoloadDump', -100000 ),
+			ScriptEvents::PRE_AUTOLOAD_DUMP  => array( 'onPreAutoloadDump', -100000 ),
 		);
 	}
 
@@ -85,4 +86,22 @@ class Plugin implements PluginInterface, EventSubscriberInterface {
 		$manifest_editor = new JetpackManifestEditor( $this->composer, $this->io );
 		$manifest_editor->update_autoload_manifests( $root_package );
 	}
+
+	/**
+	 * An event handler that runs before the autoload dump event.
+	 *
+	 * @param Event $event The event to handle.
+	 */
+	public function onPreAutoloadDump( Event $event ) {
+		$root_package = $this->composer->getPackage();
+
+		// Inject out custom autoloader for picking up new classes without re-running autoload dump.
+		$dev_autoload          = $root_package->getDevAutoload();
+		$dev_autoload['files'] = array_merge(
+			$dev_autoload['files'] ?? array(),
+			array( 'vendor/woocommerce/monorepo-plugin/autoload-dev.php' )
+		);
+
+		$root_package->setDevAutoload( $dev_autoload );
+	}
 }

plugins/woocommerce/changelog/dev-local-development-autoloading-challenge

@@ -0,0 +1,4 @@
+Significance: patch
+Type: dev
+
+Monorepo: tweak monorepo composer packages installation (no symlinking)

plugins/woocommerce/composer.json

@@ -14,7 +14,10 @@
 		},
 		{
 			"type": "path",
-			"url": "../../packages/php/monorepo-plugin"
+			"url": "../../packages/php/monorepo-plugin",
+			"options": {
+				"symlink": false
+			}
 		},
 		{
 			"type": "path",

plugins/woocommerce/composer.lock

@@ -5007,6 +5007,7 @@
                 }
             },
             "transport-options": {
+                "symlink": false,
                 "relative": true
             }
         },

plugins/woocommerce/package.json

@@ -38,7 +38,7 @@
 		"env:test": "pnpm env:dev",
 		"env:perf": "pnpm env:dev && pnpm env:performance-init",
 		"preinstall": "npx only-allow pnpm",
-		"postinstall": "XDEBUG_MODE=off composer install --quiet",
+		"postinstall": "rimraf -g vendor/woocommerce && XDEBUG_MODE=off composer install --quiet",
 		"lint": "pnpm --if-present '/^lint:lang:.*$/'",
 		"lint:changes:branch": "pnpm '/^lint:changes:branch:.*$/'",
 		"lint:fix": "pnpm --if-present '/^lint:fix:lang:.*$/'",
@@ -699,6 +699,7 @@
 		"mocha": "7.2.0",
 		"nodemon": "^3.0.2",
 		"prettier": "npm:wp-prettier@^2.8.5",
+		"rimraf": "5.0.5",
 		"stylelint": "^14.16.1",
 		"typescript": "5.3.x",
 		"uuid": "^9.0.1",

pnpm-lock.yaml

@@ -3464,6 +3464,9 @@ importers:
       prettier:
         specifier: npm:wp-prettier@^2.8.5
         version: wp-prettier@2.8.5
+      rimraf:
+        specifier: 5.0.5
+        version: 5.0.5
       stylelint:
         specifier: ^14.16.1
         version: 14.16.1