Improve logic for checking valid exporters (#414)

* Fix `wp-load.php` path in export unit tests

* Make required paths match more robust in default export process

* Throw error when no exporter can be found

* Fix not found valid exporter case

src/lib/import-export/export/export-manager.ts

@@ -8,10 +8,12 @@ export async function exportBackup(
 	onEvent: ( data: ImportExportEventData ) => void,
 	exporters: NewExporter[] = defaultExporterOptions
 ): Promise< void > {
+	let foundValidExporter;
 	for ( const Exporter of exporters ) {
 		const exporterInstance = new Exporter( exportOptions );
 		const removeExportListeners = handleEvents( exporterInstance, onEvent, ExportEvents );
-		if ( await exporterInstance.canHandle() ) {
+		foundValidExporter = await exporterInstance.canHandle();
+		if ( foundValidExporter ) {
 			try {
 				await exporterInstance.export();
 			} finally {
@@ -20,6 +22,10 @@ export async function exportBackup(
 			break;
 		}
 	}
+	if ( ! foundValidExporter ) {
+		onEvent( { event: ExportEvents.EXPORT_ERROR, data: null } );
+		throw new Error( 'No suitable exporter found for the site' );
+	}
 }
 
 export const defaultExporterOptions: NewExporter[] = [ DefaultExporter, SqlExporter ];

src/lib/import-export/export/exporters/default-exporter.ts

@@ -45,12 +45,22 @@ export class DefaultExporter extends EventEmitter implements Exporter {
 			return false;
 		}
 
-		const requiredPaths = [ 'wp-content', 'wp-includes', 'wp-load.php', 'wp-config.php' ];
+		const requiredPaths = [
+			{ path: 'wp-content', isDir: true },
+			{ path: 'wp-includes', isDir: true },
+			{ path: 'wp-load.php', isDir: false },
+			{ path: 'wp-config.php', isDir: false },
+		];
 
 		this.siteFiles = await this.getSiteFiles();
 
 		return requiredPaths.every( ( requiredPath ) =>
-			this.siteFiles.some( ( file ) => file.includes( requiredPath ) )
+			this.siteFiles.some( ( file ) => {
+				const relativePath = path.relative( this.options.site.path, file );
+				return requiredPath.isDir
+					? relativePath.startsWith( requiredPath.path )
+					: relativePath === requiredPath.path;
+			} )
 		);
 	}
 

src/lib/import-export/tests/export/export-manager.test.ts

@@ -60,4 +60,32 @@ describe( 'exportBackup', () => {
 		expect( MockExporter2 ).toHaveBeenCalledWith( mockExportOptions );
 		expect( ExportMethod2 ).toHaveBeenCalled();
 	} );
+
+	it( 'fails if no exporter is found', async () => {
+		const ExportMethod1 = jest.fn();
+		const MockExporter1 = jest.fn( () => ( {
+			canHandle: jest.fn().mockResolvedValue( false ),
+			export: ExportMethod1,
+			on: jest.fn(),
+			emit: jest.fn(),
+		} ) );
+
+		const ExportMethod2 = jest.fn();
+		const MockExporter2 = jest.fn( () => ( {
+			canHandle: jest.fn().mockResolvedValue( false ),
+			export: ExportMethod2,
+			on: jest.fn(),
+			emit: jest.fn(),
+		} ) );
+
+		const exporters: NewExporter[] = [ MockExporter1, MockExporter2 ];
+		await expect( exportBackup( mockExportOptions, jest.fn(), exporters ) ).rejects.toThrow(
+			'No suitable exporter found for the site'
+		);
+
+		expect( MockExporter1 ).toHaveBeenCalledWith( mockExportOptions );
+		expect( ExportMethod1 ).not.toHaveBeenCalled();
+		expect( MockExporter2 ).toHaveBeenCalledWith( mockExportOptions );
+		expect( ExportMethod2 ).not.toHaveBeenCalled();
+	} );
 } );

src/lib/import-export/tests/export/exporters/default-exporter.test.ts

@@ -53,7 +53,7 @@ describe( 'DefaultExporter', () => {
 		{ path: '/path/to/site/wp-content/plugins/plugin1', name: 'plugin1.php', isFile: () => true },
 		{ path: '/path/to/site/wp-content/themes/theme1', name: 'index.php', isFile: () => true },
 		{ path: '/path/to/site/wp-includes/index.php', name: 'index.php', isFile: () => true },
-		{ path: '/path/to/site/wp-load.php', name: 'wp-load.php', isFile: () => true },
+		{ path: '/path/to/site', name: 'wp-load.php', isFile: () => true },
 	];
 
 	( fsPromises.readdir as jest.Mock ).mockResolvedValue( mockFiles );