feat: make options hook async (#3660)

docs/05-plugin-development.md

@@ -124,7 +124,7 @@ You can use [`this.getModuleInfo`](guide/en/#thisgetmoduleinfomoduleid-string--m
 
 #### `options`
 Type: `(options: InputOptions) => InputOptions | null`<br>
-Kind: `sync, sequential`<br>
+Kind: `async, sequential`<br>
 Previous Hook: This is the first hook of the build phase.<br>
 Next Hook: [`buildStart`](guide/en/#buildstart)
 

src/rollup/rollup.ts

@@ -32,7 +32,7 @@ export async function rollupInternal(
 	rawInputOptions: GenericConfigObject,
 	watcher: RollupWatcher | null
 ): Promise<RollupBuild> {
-	const { options: inputOptions, unsetOptions: unsetInputOptions } = getInputOptions(
+	const { options: inputOptions, unsetOptions: unsetInputOptions } = await getInputOptions(
 		rawInputOptions,
 		watcher !== null
 	);
@@ -89,28 +89,31 @@ export async function rollupInternal(
 	return result;
 }
 
-function getInputOptions(
+async function getInputOptions(
 	rawInputOptions: GenericConfigObject,
 	watchMode: boolean
-): { options: NormalizedInputOptions; unsetOptions: Set<string> } {
+): Promise<{ options: NormalizedInputOptions; unsetOptions: Set<string> }> {
 	if (!rawInputOptions) {
 		throw new Error('You must supply an options object to rollup');
 	}
 	const rawPlugins = ensureArray(rawInputOptions.plugins) as Plugin[];
 	const { options, unsetOptions } = normalizeInputOptions(
-		rawPlugins.reduce(applyOptionHook(watchMode), rawInputOptions)
+		await rawPlugins.reduce(applyOptionHook(watchMode), Promise.resolve(rawInputOptions))
 	);
 	normalizePlugins(options.plugins, ANONYMOUS_PLUGIN_PREFIX);
 	return { options, unsetOptions };
 }
 
 function applyOptionHook(watchMode: boolean) {
-	return (inputOptions: GenericConfigObject, plugin: Plugin): GenericConfigObject => {
+	return async (
+		inputOptions: Promise<GenericConfigObject>,
+		plugin: Plugin
+	): Promise<GenericConfigObject> => {
 		if (plugin.options)
 			return (
 				(plugin.options.call(
 					{ meta: { rollupVersion, watchMode } },
-					inputOptions
+					await inputOptions
 				) as GenericConfigObject) || inputOptions
 			);
 

test/function/samples/options-async-hook/_config.js

@@ -0,0 +1,33 @@
+const assert = require('assert');
+const { promises: fs } = require('fs');
+
+module.exports = {
+	description: 'resolves promises between sequential options hooks',
+	options: {
+		input: 'super-unused',
+		treeshake: false,
+		plugins: [
+			{
+				name: 'test-plugin-1',
+				async options(options) {
+					assert.deepStrictEqual(JSON.parse(JSON.stringify(options)), {
+						input: 'super-unused',
+						plugins: [{ name: 'test-plugin-1' }, { name: 'test-plugin-2' }],
+						strictDeprecations: true,
+						treeshake: false
+					});
+					return Object.assign({}, options, {
+						input: (await fs.readFile('file.txt', 'utf8')).trim()
+					});
+				}
+			},
+			{
+				name: 'test-plugin-2',
+				options(options) {
+					assert.strictEqual(options.input, 'unused');
+					return Object.assign({}, options, { input: 'used' });
+				}
+			}
+		]
+	}
+};

test/function/samples/options-async-hook/file.txt

@@ -0,0 +1 @@
+unused

test/function/samples/options-async-hook/unused.js

@@ -0,0 +1 @@
+throw new Error('Not executed');

test/function/samples/options-async-hook/used.js

@@ -0,0 +1 @@
+export default 42;