Create chunks for virtual modules when preserving modules (#2511)

* Create test

* Enable functional tests with code-splitting and add red code splitting module order test

* Sort external and inter-chunk imports according to execution order

* Extract execution order sorting, improve some names and clean up code

* Extract module execution order analysis from Graph

* Create chunks for virtual modules when preserving modules

* Automatically deconflict virtual modules from existing ones

browser/path.ts

@@ -1,23 +1,23 @@
 export const absolutePath = /^(?:\/|(?:[A-Za-z]:)?[\\|/])/;
 export const relativePath = /^\.?\.\//;
 
-export function isAbsolute (path: string) {
+export function isAbsolute(path: string) {
 	return absolutePath.test(path);
 }
 
-export function isRelative (path: string) {
+export function isRelative(path: string) {
 	return relativePath.test(path);
 }
 
-export function normalize (path: string) {
+export function normalize(path: string) {
 	return path.replace(/\\/g, '/');
 }
 
-export function basename (path: string) {
+export function basename(path: string) {
 	return path.split(/(\/|\\)/).pop();
 }
 
-export function dirname (path: string) {
+export function dirname(path: string) {
 	const match = /(\/|\\)[^/\\]*$/.exec(path);
 	if (!match) return '.';
 
@@ -27,13 +27,13 @@ export function dirname (path: string) {
 	return dir ? dir : '/';
 }
 
-export function extname (path: string) {
+export function extname(path: string) {
 	const match = /\.[^.]+$/.exec(basename(path));
 	if (!match) return '';
 	return match[0];
 }
 
-export function relative (from: string, to: string) {
+export function relative(from: string, to: string) {
 	const fromParts = from.split(/[/\\]/).filter(Boolean);
 	const toParts = to.split(/[/\\]/).filter(Boolean);
 
@@ -56,7 +56,7 @@ export function relative (from: string, to: string) {
 	return toParts.join('/');
 }
 
-export function resolve (...paths: string[]) {
+export function resolve(...paths: string[]) {
 	let resolvedParts = paths.shift().split(/[/\\]/);
 
 	paths.forEach(path => {
@@ -76,5 +76,5 @@ export function resolve (...paths: string[]) {
 		}
 	});
 
-	return resolvedParts.join('/'); // TODO windows...
+	return resolvedParts.join('/');
 }

src/Chunk.ts

@@ -26,7 +26,7 @@ import error from './utils/error';
 import { sortByExecutionOrder } from './utils/execution-order';
 import getIndentString from './utils/getIndentString';
 import { makeLegal } from './utils/identifierHelpers';
-import { basename, dirname, normalize, relative, resolve } from './utils/path';
+import { basename, dirname, isAbsolute, normalize, relative, resolve } from './utils/path';
 import renderChunk from './utils/renderChunk';
 import { RenderOptions } from './utils/renderHelpers';
 import { makeUnique, renderNamePattern } from './utils/renderNamePattern';
@@ -1010,16 +1010,27 @@ export default class Chunk {
 		this.preRender(options, inputBase);
 	}
 
-	generateIdPreserveModules(preserveModulesRelativeDir: string) {
-		return (this.id = normalize(relative(preserveModulesRelativeDir, this.entryModule.id)));
+	generateIdPreserveModules(
+		preserveModulesRelativeDir: string,
+		existingNames: Record<string, true>
+	) {
+		const sanitizedId = this.entryModule.id.replace('\0', '_');
+		this.id = makeUnique(
+			normalize(
+				isAbsolute(this.entryModule.id)
+					? relative(preserveModulesRelativeDir, sanitizedId)
+					: '_virtual/' + basename(sanitizedId)
+			),
+			existingNames
+		);
 	}
 
 	generateId(
 		pattern: string,
 		patternName: string,
 		addons: Addons,
 		options: OutputOptions,
-		existingNames: { [name: string]: any }
+		existingNames: Record<string, true>
 	) {
 		this.id = makeUnique(
 			renderNamePattern(pattern, patternName, type => {

src/rollup/index.ts

@@ -9,7 +9,7 @@ import error from '../utils/error';
 import { writeFile } from '../utils/fs';
 import getExportMode from '../utils/getExportMode';
 import mergeOptions, { GenericConfigObject } from '../utils/mergeOptions';
-import { basename, dirname, resolve } from '../utils/path';
+import { basename, dirname, isAbsolute, resolve } from '../utils/path';
 import { SOURCEMAPPING_URL } from '../utils/sourceMappingURL';
 import { getTimings, initialiseTimers, timeEnd, timeStart } from '../utils/timers';
 import { Watcher } from '../watch';
@@ -262,9 +262,10 @@ export default function rollup(
 					// populate asset files into output
 					const assetFileNames = outputOptions.assetFileNames || 'assets/[name]-[hash][extname]';
 					const outputBundle: OutputBundle = graph.finaliseAssets(assetFileNames);
-
 					const inputBase = commondir(
-						chunks.filter(chunk => chunk.entryModule).map(chunk => chunk.entryModule.id)
+						chunks
+							.filter(chunk => chunk.entryModule && isAbsolute(chunk.entryModule.id))
+							.map(chunk => chunk.entryModule.id)
 					);
 
 					return graph.pluginDriver
@@ -299,7 +300,7 @@ export default function rollup(
 												: <string>inputOptions.input)
 									);
 								} else if (inputOptions.experimentalPreserveModules) {
-									chunk.generateIdPreserveModules(inputBase);
+									chunk.generateIdPreserveModules(inputBase, usedIds);
 								} else {
 									let pattern, patternName;
 									if (chunk.isEntryModuleFacade) {
@@ -310,8 +311,8 @@ export default function rollup(
 										patternName = 'output.chunkFileNames';
 									}
 									chunk.generateId(pattern, patternName, addons, outputOptions, usedIds);
-									usedIds[chunk.id] = true;
 								}
+								usedIds[chunk.id] = true;
 							}
 
 							// assign to outputBundle

src/utils/commondir.ts

@@ -2,6 +2,7 @@ import * as path from './path';
 
 // ported from https://github.com/substack/node-commondir
 export default function commondir(files: string[]) {
+	if (files.length === 0) return '/';
 	if (files.length === 1) return path.dirname(files[0]);
 	const commonSegments = files.slice(1).reduce((commonSegments, file) => {
 		const pathSegements = file.split(/\/+|\\+/);

src/utils/path.ts

@@ -1,5 +1,5 @@
-export const absolutePath = /^(?:\/|(?:[A-Za-z]:)?[\\|/])/;
-export const relativePath = /^\.?\.\//;
+const absolutePath = /^(?:\/|(?:[A-Za-z]:)?[\\|/])/;
+const relativePath = /^\.?\.\//;
 
 export function isAbsolute(path: string) {
 	return absolutePath.test(path);

test/chunking-form/samples/preserve-modules-virtual-modules/_config.js

@@ -0,0 +1,23 @@
+module.exports = {
+	solo: true,
+	description: 'Generates actual files for virtual modules when preserving modules',
+	options: {
+		input: 'main.js',
+		experimentalPreserveModules: true,
+		plugins: [
+			{
+				resolveId(id) {
+					if (id === '\0virtualModule') return id;
+				},
+				load(id) {
+					if (id !== '\0virtualModule') return null;
+					return 'export const virtual = "Virtual!";\n';
+				},
+				transform(code, id) {
+					if (id === '\0virtualModule') return null;
+					return 'import {virtual} from "\0virtualModule";\n' + code;
+				}
+			}
+		]
+	}
+};

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/amd/_virtual/_virtualModule

@@ -0,0 +1,7 @@
+define(['exports'], function (exports) { 'use strict';
+
+	const virtual = "Virtual!";
+
+	exports.virtual = virtual;
+
+});

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/amd/main.js

@@ -0,0 +1,5 @@
+define(['./_virtual/_virtualModule'], function (__chunk_1) { 'use strict';
+
+	assert.equal(__chunk_1.virtual, 'Virtual!');
+
+});

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/cjs/_virtual/_virtualModule

@@ -0,0 +1,5 @@
+'use strict';
+
+const virtual = "Virtual!";
+
+exports.virtual = virtual;

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/cjs/main.js

@@ -0,0 +1,5 @@
+'use strict';
+
+var __chunk_1 = require('./_virtual/_virtualModule');
+
+assert.equal(__chunk_1.virtual, 'Virtual!');

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/es/_virtual/_virtualModule

@@ -0,0 +1,3 @@
+const virtual = "Virtual!";
+
+export { virtual };

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/es/main.js

@@ -0,0 +1,3 @@
+import { virtual } from './_virtual/_virtualModule';
+
+assert.equal(virtual, 'Virtual!');

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/system/_virtual/_virtualModule

@@ -0,0 +1,10 @@
+System.register([], function (exports, module) {
+	'use strict';
+	return {
+		execute: function () {
+
+			const virtual = exports('virtual', "Virtual!");
+
+		}
+	};
+});

test/chunking-form/samples/preserve-modules-virtual-modules/_expected/system/main.js

@@ -0,0 +1,14 @@
+System.register(['./_virtual/_virtualModule'], function (exports, module) {
+	'use strict';
+	var virtual;
+	return {
+		setters: [function (module) {
+			virtual = module.virtual;
+		}],
+		execute: function () {
+
+			assert.equal(virtual, 'Virtual!');
+
+		}
+	};
+});

test/chunking-form/samples/preserve-modules-virtual-modules/main.js

@@ -0,0 +1 @@
+assert.equal(virtual, 'Virtual!');

test/function/index.js

@@ -31,7 +31,7 @@ function runSingleFileTest(code, configContext) {
 
 function runCodeSplitTest(output, configContext) {
 	const requireFromOutputVia = importer => importee => {
-		const outputId = path.join(path.dirname(importer), importee);
+		const outputId = path.posix.join(path.posix.dirname(importer), importee);
 		const chunk = output[outputId];
 		if (chunk) {
 			return requireWithContext(

test/function/samples/preserve-modules-virtual-modules-conflict/_config.js

@@ -0,0 +1,36 @@
+const assert = require('assert');
+
+module.exports = {
+	description: 'Generates actual files for virtual modules when preserving modules',
+	options: {
+		input: ['main.js'],
+		experimentalCodeSplitting: true,
+		experimentalPreserveModules: true,
+		plugins: [
+			{
+				resolveId(id) {
+					if (id === '\0virtualModule.js') return id;
+				},
+				load(id) {
+					if (id !== '\0virtualModule.js') return null;
+					return 'export const virtual = "Virtual!";\n';
+				},
+				transform(code, id) {
+					if (id === '\0virtualModule.js') return null;
+					return 'import {virtual} from "\0virtualModule.js";\n' + code;
+				}
+			}
+		]
+	},
+	bundle(bundle) {
+		return bundle
+			.generate({ format: 'esm' })
+			.then(generated =>
+				assert.deepEqual(Object.keys(generated.output), [
+					'_virtual/_virtualModule.js',
+					'_virtual/_virtualModule2.js',
+					'main.js'
+				])
+			);
+	}
+};

test/function/samples/preserve-modules-virtual-modules-conflict/_virtual/_virtualModule.js

@@ -0,0 +1,3 @@
+export const notSoVirtual = 'real';
+
+assert.equal(virtual, 'Virtual!');

test/function/samples/preserve-modules-virtual-modules-conflict/main.js

@@ -0,0 +1,4 @@
+import { notSoVirtual } from './_virtual/_virtualModule';
+
+assert.equal(virtual, 'Virtual!');
+assert.equal(notSoVirtual, 'real');

test/function/samples/preserve-modules-virtual-modules/_config.js

@@ -0,0 +1,36 @@
+const assert = require('assert');
+
+module.exports = {
+	description: 'Generates actual files for virtual modules when preserving modules',
+	options: {
+		input: ['main.js'],
+		experimentalCodeSplitting: true,
+		experimentalPreserveModules: true,
+		plugins: [
+			{
+				resolveId(id) {
+					if (id === '\0virtualModule') return id;
+				},
+				load(id) {
+					if (id !== '\0virtualModule') return null;
+					return 'export const virtual = "Virtual!";\n';
+				},
+				transform(code, id) {
+					if (id === '\0virtualModule') return null;
+					return 'import {virtual} from "\0virtualModule";\n' + code;
+				}
+			}
+		]
+	},
+	bundle(bundle) {
+		return bundle
+			.generate({ format: 'esm' })
+			.then(generated =>
+				assert.deepEqual(Object.keys(generated.output), [
+					'_virtual/_virtualModule',
+					'lib/lib.js',
+					'main.js'
+				])
+			);
+	}
+};

test/function/samples/preserve-modules-virtual-modules/lib/lib.js

@@ -0,0 +1 @@
+assert.equal(virtual, 'Virtual!');

test/function/samples/preserve-modules-virtual-modules/main.js

@@ -0,0 +1,3 @@
+import './lib/lib.js';
+
+assert.equal(virtual, 'Virtual!');

test/utils.js

@@ -160,8 +160,10 @@ function runTestsInDir(dir, runTest) {
 	const fileNames = sander.readdirSync(dir);
 
 	if (fileNames.indexOf('_config.js') >= 0) {
+		removeOldOutput(dir);
 		loadConfigAndRunTest(dir, runTest);
 	} else if (fileNames.indexOf('_actual') >= 0 || fileNames.indexOf('_actual.js') >= 0) {
+		removeOldOutput(dir);
 		removeOldTest(dir);
 	} else {
 		describe(path.basename(dir), () => {
@@ -174,7 +176,6 @@ function runTestsInDir(dir, runTest) {
 }
 
 function loadConfigAndRunTest(dir, runTest) {
-	removeOldOutput(dir);
 	const config = loadConfig(dir + '/_config.js');
 	if (
 		config &&