Assign chunk IDs before creating outputBundle chunks

src/rollup/index.ts

@@ -282,11 +282,9 @@ export default function rollup(
 							}
 
 							// name all chunks
+							const usedIds: Record<string, true> = {};
 							for (let i = 0; i < chunks.length; i++) {
 								const chunk = chunks[i];
-								const imports = chunk.getImportIds();
-								const exports = chunk.getExportNames();
-								const modules = chunk.renderedModules;
 
 								if (chunk === singleChunk) {
 									singleChunk.id = basename(
@@ -306,15 +304,21 @@ export default function rollup(
 										pattern = outputOptions.chunkFileNames || '[name]-[hash].js';
 										patternName = 'output.chunkFileNames';
 									}
-									chunk.generateId(pattern, patternName, addons, outputOptions, outputBundle);
+									chunk.generateId(pattern, patternName, addons, outputOptions, usedIds);
+									usedIds[chunk.id] = true;
 								}
+							}
+
+							// assign to outputBundle
+							for (let i = 0; i < chunks.length; i++) {
+								const chunk = chunks[i];
 
 								outputBundle[chunk.id] = {
 									fileName: chunk.id,
 									isEntry: chunk.entryModule !== undefined,
-									imports,
-									exports,
-									modules,
+									imports: chunk.getImportIds(),
+									exports: chunk.getExportNames(),
+									modules: chunk.renderedModules,
 									code: undefined,
 									map: undefined
 								};

test/hooks/index.js

@@ -829,13 +829,13 @@ module.exports = input;
 						plugins: [
 							loader({ input: `alert('hello')` }),
 							{
-								name: name,
+								name,
 								buildStart() {
 									this.cache.set('asdf', 'asdf');
 								}
 							},
 							{
-								name: name,
+								name,
 								buildStart() {
 									this.cache.set('asdf', 'asdf');
 								}
@@ -845,7 +845,7 @@ module.exports = input;
 					.catch(err => {
 						assert.equal(err.code, 'PLUGIN_ERROR');
 						assert.equal(err.pluginCode, 'DUPLICATE_PLUGIN_NAME');
-						assert.equal(err.message.includes(name), true)
+						assert.equal(err.message.includes(name), true);
 					});
 			});
 	});
@@ -1073,4 +1073,62 @@ module.exports = input;
 				assert.equal(renderErrorCount, 1, 'renderError count');
 			});
 	});
+
+	it('assigns chunk IDs before creating outputBundle chunks', () => {
+		const chunks = [];
+		return rollup
+			.rollup({
+				input: 'input',
+				experimentalCodeSplitting: true,
+				plugins: [
+					loader({
+						input: `export default [import('a'), import('b')];`,
+						a: `import d from 'd'; import c from 'c'; export default () => c();`,
+						b: `import c from 'c'; export default () => c();`,
+						c: `export default () => console.log('c');`,
+						d: `export default {};`
+					}),
+					{
+						renderChunk(code, chunk, options) {
+							chunks.push({
+								fileName: chunk.fileName,
+								imports: chunk.imports,
+								modules: Object.keys(chunk.modules)
+							});
+						}
+					}
+				]
+			})
+			.then(bundle =>
+				bundle.generate({
+					entryFileNames: '[name].js',
+					chunkFileNames: '[name].js',
+					format: 'esm'
+				})
+			)
+			.then(() => {
+				assert.deepEqual(chunks, [
+					{
+						fileName: 'input.js',
+						imports: [],
+						modules: ['input']
+					},
+					{
+						fileName: 'a.js',
+						imports: ['chunk.js'],
+						modules: ['d', 'a']
+					},
+					{
+						fileName: 'chunk.js',
+						imports: [],
+						modules: ['c']
+					},
+					{
+						fileName: 'b.js',
+						imports: ['chunk.js'],
+						modules: ['b']
+					}
+				]);
+			});
+	});
 });