Add support for replacement files.

Author: johnbillion

composer.json

@@ -60,7 +60,10 @@
 					"library/README.md",
 					"LICENSE",
 					"README.md"
-				]
+				],
+				"replace": {
+					"library/Requests.php": "Requests.php"
+				}
 			},
 			"simplepie/simplepie": {
 				"target": "src/wp-includes/SimplePie",

tools/composer/replacements/Requests.php

@@ -0,0 +1,12 @@
+<?php
+/**
+ * Loads the old Requests class file when the autoloader
+ * references the original PSR-0 Requests class.
+ *
+ * @deprecated 6.2.0
+ * @package WordPress
+ * @subpackage Requests
+ * @since 6.2.0
+ */
+
+include_once ABSPATH . WPINC . '/class-requests.php';

tools/composer/src/CustomInstaller.php

@@ -110,9 +110,37 @@ private function modifyPaths( PackageInterface $package ): void {
 		$installPath = $this->getInstallPath( $package );
 
 		$this->applySourceSubdirectory( $package, $installPath );
+		$this->applyReplacements( $package, $installPath );
 		$this->applyIgnorePatterns( $package, $installPath );
 	}
 
+	/**
+	 * Apply file replacements from custom replacement files.
+	 *
+	 * @param PackageInterface $package     The package.
+	 * @param string           $installPath The installation path.
+	 */
+	private function applyReplacements( PackageInterface $package, string $installPath ): void {
+		$packageName = $package->getName();
+
+		if ( ! isset( $this->installerPaths[ $packageName ]['replace'] ) ) {
+			return;
+		}
+
+		$filesystem      = new Filesystem();
+		$replacementsDir = realpath( getcwd() ) . '/tools/composer/replacements';
+
+		foreach ( $this->installerPaths[ $packageName ]['replace'] as $target => $source ) {
+			$sourcePath = $replacementsDir . '/' . $source;
+
+			if ( ! file_exists( $sourcePath ) ) {
+				throw new \RuntimeException( "Replacement file 'tools/composer/replacements/{$source}' does not exist for package '{$packageName}'." );
+			}
+
+			$filesystem->copy( $sourcePath, $installPath . '/' . $target );
+		}
+	}
+
 	/**
 	 * Apply ignore patterns to remove unwanted files after installation.
 	 *