Use Rolldown in build-tools

.changelog/20260515104307_ci_4316_use_rolldown_for_build_tools.md

@@ -0,0 +1,9 @@
+---
+type: Major breaking change
+scope:
+  - ckeditor5-dev-build-tools
+---
+
+Removed output path rewriting from `ckeditor5-dev-build-tools` except for package imports rewritten to `ckeditor5` and `ckeditor5-premium-features` in browser builds.
+
+The `rewrite` JavaScript API option was removed. Imports using `ckeditor5/src/*` and `ckeditor5-collaboration/src/*` are no longer rewritten automatically.

.changelog/20260518155955_ci_4316_use_rolldown_for_build_tools.md

@@ -0,0 +1,9 @@
+---
+type: Major breaking change
+scope:
+  - ckeditor5-dev-build-tools
+---
+
+Replaced Rollup with Rolldown in `ckeditor5-dev-build-tools`.
+
+Rollup-specific dependencies that are no longer needed because Rolldown provides equivalent features out of the box were removed.

.changelog/20260518155957_ci_4316_use_rolldown_for_build_tools.md

@@ -0,0 +1,9 @@
+---
+type: Major breaking change
+scope:
+  - ckeditor5-dev-build-tools
+---
+
+Changed `ckeditor5-dev-build-tools` to assume that package sources use TypeScript isolated declarations.
+
+Declaration files are now generated without invoking TypeScript, so builds no longer perform type checking.

.changelog/20260518155959_ci_4316_use_rolldown_for_build_tools.md

@@ -0,0 +1,7 @@
+---
+type: Feature
+scope:
+  - ckeditor5-dev-build-tools
+---
+
+Added the `declarationFiles` plugin to `ckeditor5-dev-build-tools` for generating `.d.ts` files from TypeScript sources that use isolated declarations.

.changelog/20260518160000_ci_4316_use_rolldown_for_build_tools.md

@@ -0,0 +1,9 @@
+---
+type: Major breaking change
+scope:
+  - ckeditor5-dev-build-tools
+---
+
+Removed the `loadTypeScriptSources`, `replaceImports`, and `emitCss` exports from `ckeditor5-dev-build-tools`.
+
+The `loadTypeScriptSources` and `replaceImports` behavior is now handled by Rolldown. The `bundleCss` plugin now ensures that a CSS file is always emitted, including when the generated file is empty.

.changelog/20260518160002_ci_4316_use_rolldown_for_build_tools.md

@@ -0,0 +1,7 @@
+---
+type: Other
+scope:
+  - ckeditor5-dev-build-tools
+---
+
+Improved the performance of selected `ckeditor5-dev-build-tools` plugins.

package.json

@@ -30,7 +30,6 @@
     "lint-staged": "^16.4.0",
     "listr2": "^8.3.3",
     "minimist": "^1.2.8",
-    "oxc-transform": "^0.112.0",
     "semver": "^7.7.4",
     "typescript": "5.5.4",
     "upath": "^2.0.1",

packages/ckeditor5-dev-build-tools/README.md

@@ -184,18 +184,6 @@ When using the JavaScript API, the option must be an array.
 
 **Example value:** `external: [ 'lodash', 'moment' ]`
 
-#### `rewrite`
-
-**Type:** `string[]`
-
-**Default value:** `[]`
-
-A list of imports to rewrite in the output file. This option can be used if one of the dependencies provided in `external` has a separate build for the new install methods that should be used instead of the one used in the source code.
-
-This option is only available for the JavaScript API.
-
-**Example value:** `rewrite: [ 'dependency', 'dependency/dist/index.js' ]`
-
 ## Changelog
 
 See the [`CHANGELOG.md`](https://github.com/ckeditor/ckeditor5-dev/blob/master/packages/ckeditor5-dev-bump-year/CHANGELOG.md) file.

packages/ckeditor5-dev-build-tools/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@ckeditor/ckeditor5-dev-build-tools",
   "version": "55.6.3",
-  "description": "Rollup-based tools used to build CKEditor 5 packages.",
+  "description": "Rolldown-based tools used to build CKEditor 5 packages.",
   "keywords": [],
   "author": "CKSource (http://cksource.com/)",
   "license": "GPL-2.0-or-later",
@@ -27,47 +27,35 @@
     "ckeditor5-dev-build-tools": "bin/build-project.js"
   },
   "dependencies": {
-    "@rollup/plugin-commonjs": "^28.0.9",
-    "@rollup/plugin-json": "^6.1.0",
-    "@rollup/plugin-node-resolve": "^16.0.3",
-    "@rollup/plugin-swc": "^0.4.0",
-    "@rollup/plugin-terser": "^1.0.0",
-    "@rollup/plugin-typescript": "12.3.0",
     "@rollup/pluginutils": "^5.3.0",
-    "@swc/core": "^1.15.24",
     "cssnano": "^7.1.4",
     "cssnano-preset-lite": "^4.0.4",
     "es-toolkit": "^1.45.1",
-    "estree-walker": "^3.0.3",
     "glob": "^13.0.6",
     "lightningcss": "^1.32.0",
     "magic-string": "^0.30.21",
     "pofile": "^1.1.4",
     "purgecss": "^8.0.0",
-    "rollup": "^4.60.1",
-    "rollup-plugin-svg-import": "^3.0.0",
+    "rolldown": "^1.0.3",
     "source-map": "^0.7.6",
     "upath": "^2.0.1"
   },
   "devDependencies": {
     "@types/css": "^0.0.38",
     "@types/node": "^22.19.17",
     "@vitest/coverage-v8": "^4.1.2",
-    "rolldown": "^1.0.0",
     "type-fest": "^4.41.0",
     "vitest": "^4.1.2"
   },
   "scripts": {
-    "build": "rolldown -c rolldown.config.js",
-    "dev": "rolldown -c rolldown.config.js --watch",
+    "build": "rolldown -c rolldown.config.ts",
+    "dev": "rolldown -c rolldown.config.ts --watch",
     "test": "vitest run --config vitest.config.ts",
     "coverage": "vitest run --config vitest.config.ts --coverage",
     "test:dev": "vitest dev"
   },
   "depcheckIgnore": [
     "@types/css",
-    "@vitest/coverage-v8",
-    "estree",
-    "typescript"
+    "@vitest/coverage-v8"
   ]
 }

packages/ckeditor5-dev-build-tools/rolldown.config.js → packages/ckeditor5-dev-build-tools/rolldown.config.ts

@@ -4,12 +4,17 @@
  */
 
 import { defineConfig } from 'rolldown';
-import { declarationFilesPlugin } from '../../scripts/plugin-declarations.js';
+import { declarationFiles } from './src/plugins/declarations.js';
 import pkg from './package.json' with { type: 'json' };
 
+const packageJson = pkg as {
+	dependencies?: Record<string, string>;
+	peerDependencies?: Record<string, string>;
+};
+
 const externals = [
-	...Object.keys( pkg.dependencies || {} ),
-	...Object.keys( pkg.peerDependencies || {} )
+	...Object.keys( packageJson.dependencies || {} ),
+	...Object.keys( packageJson.peerDependencies || {} )
 ];
 
 export default defineConfig( {
@@ -22,7 +27,9 @@ export default defineConfig( {
 		assetFileNames: '[name][extname]'
 	},
 	plugins: [
-		declarationFilesPlugin()
+		declarationFiles( {
+			sourceDirectory: 'src'
+		} )
 	],
 	external: id => externals.some( name => id.startsWith( name ) )
 } );

packages/ckeditor5-dev-build-tools/src/build.ts

@@ -7,11 +7,13 @@ import fs from 'node:fs';
 import url from 'node:url';
 import { styleText, parseArgs } from 'node:util';
 import path from 'upath';
-import { rollup, type RollupOutput, type GlobalsOption, type LogLevelOption } from 'rollup';
+import { rolldown, type LogLevelOption, type OutputOptions, type RolldownOutput } from 'rolldown';
 import { loadSourcemaps } from './plugins/loadSourcemaps.js';
-import { getRollupConfig } from './config.js';
+import { getRolldownConfig } from './config.js';
 import { camelizeObjectKeys, removeWhitespace, getOptionalPlugin } from './utils.js';
 
+type GlobalsOption = Record<string, string> | ( ( name: string ) => string );
+
 export interface BuildOptions {
 	input: string;
 	output: string;
@@ -20,7 +22,6 @@ export interface BuildOptions {
 	globals: GlobalsOption | Array<string>;
 	banner: string;
 	external: Array<string>;
-	rewrite: Array<[string, string]>;
 	declarations: boolean;
 	translations: string;
 	sourceMap: boolean;
@@ -39,7 +40,6 @@ export const defaultOptions: BuildOptions = {
 	globals: {},
 	banner: '',
 	external: [],
-	rewrite: [],
 	declarations: false,
 	translations: '',
 	sourceMap: false,
@@ -107,20 +107,20 @@ function normalizeGlobalsParameter( globals: GlobalsOption | Array<string> ): Gl
 /**
  * Generates `UMD` build based on previous `ESM` build.
  */
-async function generateUmdBuild( args: BuildOptions, bundle: RollupOutput ): Promise<RollupOutput> {
+async function generateUmdBuild( args: BuildOptions, bundle: RolldownOutput ): Promise<RolldownOutput> {
 	args.input = args.output;
 
 	const { dir, name } = path.parse( args.output );
 	// eslint-disable-next-line @typescript-eslint/no-unused-vars
-	const { plugins, ...config } = await getRollupConfig( args );
+	const { plugins, resolve, tsconfig, transform, moduleTypes, output, ...config } = await getRolldownConfig( args );
 
 	/**
 	 * Ignore the plugins we used for the ESM build. Instead, add a new plugin to not only
-	 * load the source code of the dependencies (which is the default in Rollup for better
+	 * load the source code of the dependencies (which is the default in Rolldown for better
 	 * performance), but also their source maps to generate a proper final source map for
 	 * the UMD bundle.
 	 */
-	const build = await rollup( {
+	const build = await rolldown( {
 		...config,
 		plugins: [
 			getOptionalPlugin(
@@ -131,9 +131,10 @@ async function generateUmdBuild( args: BuildOptions, bundle: RollupOutput ): Pro
 	} );
 
 	const umdBundle = await build.write( {
+		...( output as OutputOptions ),
 		format: 'umd',
 		file: path.join( dir, `${ name }.umd.js` ),
-		inlineDynamicImports: true,
+		codeSplitting: false,
 		assetFileNames: '[name][extname]',
 		sourcemap: args.sourceMap,
 		name: args.name,
@@ -148,7 +149,7 @@ async function generateUmdBuild( args: BuildOptions, bundle: RollupOutput ): Pro
 			...bundle.output,
 			...umdBundle.output
 		]
-	};
+	} as unknown as RolldownOutput;
 }
 
 /**
@@ -196,7 +197,7 @@ async function normalizeOptions( options: Partial<BuildOptions> ): Promise<Build
  */
 export async function build(
 	options: Partial<BuildOptions> = getCliArguments()
-): Promise<RollupOutput> {
+): Promise<RolldownOutput> {
 	try {
 		const args: BuildOptions = await normalizeOptions( options );
 
@@ -210,22 +211,23 @@ export async function build(
 		}
 
 		/**
-		 * Create Rollup configuration based on provided arguments.
+		 * Create Rolldown configuration based on provided arguments.
 		 */
-		const config = await getRollupConfig( args );
+		const { output, ...config } = await getRolldownConfig( args );
 
 		/**
-		 * Run Rollup to generate bundles.
+		 * Run Rolldown to generate bundles.
 		 */
-		const build = await rollup( config );
+		const build = await rolldown( config );
 
 		/**
 		 * Write bundles to the filesystem.
 		 */
 		const bundle = await build.write( {
+			...( output as OutputOptions ),
 			format: 'esm',
 			file: args.output,
-			inlineDynamicImports: true,
+			codeSplitting: false,
 			assetFileNames: '[name][extname]',
 			sourcemap: args.sourceMap,
 			name: args.name
@@ -242,7 +244,7 @@ export async function build(
 	} catch ( error: any ) {
 		let message: string;
 
-		if ( error.name === 'RollupError' ) {
+		if ( error.id ) {
 			message = `
 				${ styleText( 'red', 'ERROR: Error occurred when processing the file ' + error.id ) }.
 				${ error.message }