Upgrade/Install: Return WP_Error when source files cannot be found.

Fixes a fatal error in `array_keys()` (PHP 8.0+) as `$wp_filesystem->dirlist()` will return `false` when the source directory doesn't exist or becomes unreadable for some reason.

Props: verygoode, lifelightweb, da5f656f, costdev, afragen, azaozz
Fixes #61114

git-svn-id: https://develop.svn.wordpress.org/trunk@59257 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-upgrader.php

@@ -204,6 +204,7 @@ class WP_Upgrader {
 		$this->strings['mkdir_failed']         = __( 'Could not create directory.' );
 		$this->strings['incompatible_archive'] = __( 'The package could not be installed.' );
 		$this->strings['files_not_writable']   = __( 'The update cannot be installed because some files could not be copied. This is usually due to inconsistent file permissions.' );
+		$this->strings['dir_not_readable']     = __( 'A directory could not be read.' );
 
 		$this->strings['maintenance_start'] = __( 'Enabling Maintenance mode…' );
 		$this->strings['maintenance_end']   = __( 'Disabling Maintenance mode…' );
@@ -558,7 +559,13 @@ class WP_Upgrader {
 		$remote_source     = $args['source'];
 		$local_destination = $destination;
 
-		$source_files       = array_keys( $wp_filesystem->dirlist( $remote_source ) );
+		$dirlist = $wp_filesystem->dirlist( $remote_source );
+
+		if ( false === $dirlist ) {
+			return new WP_Error( 'source_read_failed', $this->strings['fs_error'], $this->strings['dir_not_readable'] );
+		}
+
+		$source_files       = array_keys( $dirlist );
 		$remote_destination = $wp_filesystem->find_folder( $local_destination );
 
 		// Locate which directory to copy to the new folder. This is based on the actual folder holding the files.
@@ -605,7 +612,13 @@ class WP_Upgrader {
 
 		// Has the source location changed? If so, we need a new source_files list.
 		if ( $source !== $remote_source ) {
-			$source_files = array_keys( $wp_filesystem->dirlist( $source ) );
+			$dirlist = $wp_filesystem->dirlist( $source );
+
+			if ( false === $dirlist ) {
+				return new WP_Error( 'new_source_read_failed', $this->strings['fs_error'], $this->strings['dir_not_readable'] );
+			}
+
+			$source_files = array_keys( $dirlist );
 		}
 
 		/*

tests/phpunit/tests/admin/wpUpgrader.php

@@ -948,6 +948,107 @@ class Tests_Admin_WpUpgrader extends WP_UnitTestCase {
 		);
 	}
 
+	/**
+	 * Tests that `WP_Upgrader::install_package()` returns a WP_Error object
+	 * when the source directory's file list cannot be retrieved.
+	 *
+	 * @ticket 61114
+	 *
+	 * @covers WP_Upgrader::install_package
+	 */
+	public function test_install_package_should_return_wp_error_when_source_directory_file_list_cannot_be_retrieved() {
+		self::$instance->generic_strings();
+
+		self::$upgrader_skin_mock
+				->expects( $this->once() )
+				->method( 'feedback' )
+				->with( 'installing_package' );
+
+		self::$wp_filesystem_mock
+				->expects( $this->once() )
+				->method( 'dirlist' )
+				->willReturn( false );
+
+		$args = array(
+			'source'      => '/',
+			'destination' => '/',
+		);
+
+		$actual = self::$instance->install_package( $args );
+
+		$this->assertWPError(
+			$actual,
+			'WP_Upgrader::install_package() did not return a WP_Error object'
+		);
+
+		$this->assertSame(
+			'source_read_failed',
+			$actual->get_error_code(),
+			'Unexpected WP_Error code'
+		);
+	}
+
+	/**
+	 * Tests that `WP_Upgrader::install_package()` returns a WP_Error object
+	 * when the source directory is filtered and its file list cannot be retrieved.
+	 *
+	 * @ticket 61114
+	 *
+	 * @covers WP_Upgrader::install_package
+	 *
+	 * @runInSeparateProcess
+	 * @preserveGlobalState disabled
+	 */
+	public function test_install_package_should_return_wp_error_when_a_filtered_source_directory_file_list_cannot_be_retrieved() {
+		define( 'FS_CHMOD_DIR', 0755 );
+
+		self::$instance->generic_strings();
+
+		self::$upgrader_skin_mock
+				->expects( $this->once() )
+				->method( 'feedback' )
+				->with( 'installing_package' );
+
+		$first_source = array(
+			'subdir' => array(
+				'name'  => 'subdir',
+				'type'  => 'd',
+				'files' => array( 'subfile.php' ),
+			),
+		);
+
+		self::$wp_filesystem_mock
+				->expects( $this->exactly( 2 ) )
+				->method( 'dirlist' )
+				->willReturn( $first_source, false );
+
+		$args = array(
+			'source'      => '/',
+			'destination' => '/',
+		);
+
+		// Filter the source to something else.
+		add_filter(
+			'upgrader_source_selection',
+			static function () {
+				return '/not_original_source/';
+			}
+		);
+
+		$actual = self::$instance->install_package( $args );
+
+		$this->assertWPError(
+			$actual,
+			'WP_Upgrader::install_package() did not return a WP_Error object'
+		);
+
+		$this->assertSame(
+			'new_source_read_failed',
+			$actual->get_error_code(),
+			'Unexpected WP_Error code'
+		);
+	}
+
 	/**
 	 * Tests that `WP_Upgrader::install_package()` adds a trailing slash to
 	 * the source directory of a single file.