Hash the directory name of a package on install.

inc/packages/namespace.php

@@ -34,6 +34,7 @@
 function bootstrap() {
 	Admin\bootstrap();
 	WP_CLI\bootstrap();
+	add_filter( 'upgrader_source_selection', __NAMESPACE__ . '\\move_package_during_install', 10, 4 );
 }
 
 /**
@@ -110,6 +111,55 @@ function get_did_document( string $id ) {
 	return $document;
 }
 
+/**
+ * Get a package's DID by its path.
+ *
+ * @param string $path The absolute path to the package's directory or main file.
+ * @param string $type The type of package. Allowed types are 'plugin' or 'theme'.
+ * @return DID|WP_Error The DID object on success, WP_Error on failure.
+ */
+function get_did_by_path( $path, $type ) {
+	global $wp_filesystem;
+
+	if ( $type === 'theme' ) {
+		if ( ! str_ends_with( $path, 'style.css' ) ) {
+			$path = trailingslashit( $path ) . 'style.css';
+		}
+
+		$id = get_file_data( $path, [ 'id' => 'Theme ID' ] )['id'];
+		if ( $id ) {
+			return parse_did( $id );
+		}
+	}
+
+	if ( $type === 'plugin' ) {
+		if ( str_ends_with( $path, '.php' ) ) {
+			$id = get_file_data( $path, [ 'id' => 'Plugin ID' ] )['id'];
+			return parse_did( $id );
+		}
+
+		$files = $wp_filesystem->dirlist( $path ) ?: false;
+		if ( ! $files ) {
+			// Finding a DID is impossible.
+			return new WP_Error( 'fair.packages.dirlist_failed', __( "The package's file list could not be retrieved.", 'fair' ) );
+		}
+
+		foreach ( $files as $filename => $data ) {
+			if ( $data['type'] !== 'f' || ! str_ends_with( $filename, '.php' ) ) {
+				continue;
+			}
+
+			$filepath = trailingslashit( $path ) . $filename;
+			$id = get_file_data( $filepath, [ 'id' => 'Plugin ID' ] )['id'];
+			if ( $id ) {
+				return parse_did( $id );
+			}
+		}
+	}
+
+	return new WP_Error( 'fair.packages.none_found', __( 'No FAIR packages were found.', 'fair' ) );
+}
+
 /**
  * Fetch metadata for a package.
  *
@@ -740,6 +790,58 @@ function maybe_rename_on_package_download( string $source, string $remote_source
 	return trailingslashit( $new_source );
 }
 
+/**
+ * Move a package to the correctly named directory during installation.
+ *
+ * @param string|WP_Error $source        Path of $source, or a WP_Error object.
+ * @param string          $remote_source Path of $remote_source.
+ * @param WP_Upgrader     $upgrader      An Upgrader object.
+ * @param array           $hook_extra    Array of hook data.
+ * @return string|WP_Error The correct directory path for installation, or a WP_Error object.
+ */
+function move_package_during_install( $source, string $remote_source, WP_Upgrader $upgrader, array $hook_extra ) {
+	global $wp_filesystem;
+
+	if ( is_wp_error( $source ) ) {
+		return $source;
+	}
+
+	if ( ! isset( $hook_extra['action'] ) || $hook_extra['action'] !== 'install' ) {
+		// Other actions are handled elsewhere.
+		return $source;
+	}
+
+	if ( ! in_array( $hook_extra['type'] ?? '', [ 'plugin', 'theme' ], true ) ) {
+		// This package type is not supported.
+		return $source;
+	}
+
+	$did = get_did_by_path( $source, $hook_extra['type'] );
+	if ( is_wp_error( $did ) ) {
+		// This isn't a valid FAIR package.
+		return $source;
+	}
+
+	$did_hash = get_did_hash( $did->get_id() );
+	if ( str_ends_with( $source, "{$did_hash}/" ) ) {
+		// The directory name is likely already correct.
+		return $source;
+	}
+
+	$metadata = fetch_package_metadata( $did->get_id() );
+	if ( is_wp_error( $metadata ) || trim( $metadata->slug ?? '' ) === '' ) {
+		// Cannot guarantee a slug-didhash format. dir-didhash is the best achievable.
+		$new_source = untrailingslashit( $source ) . "-{$did_hash}/";
+	} else {
+		$new_source = dirname( untrailingslashit( $source ), 2 ) . "/{$metadata->slug}-{$did_hash}/";
+	}
+
+	// Core must be able to find the new source directory.
+	$wp_filesystem->move( $source, $new_source, true );
+
+	return $new_source;
+}
+
 /**
  * Add FAIR ReleaseDocument data to cache.
  *