support addWatchFile

src/rollup/types.d.ts

@@ -92,6 +92,7 @@ export interface PluginCache {
 
 export interface PluginContext {
 	watcher: Watcher;
+	addWatchFile: (id: string) => void;
 	cache: PluginCache;
 	resolveId: ResolveIdHook;
 	isExternal: IsExternal;

src/utils/pluginDriver.ts

@@ -12,6 +12,7 @@ import {
 import { createAssetPluginHooks, EmitAsset } from './assetHooks';
 import { getRollupDefaultPlugin } from './default-plugin';
 import error from './error';
+import { resolve } from './path';
 
 export interface PluginDriver {
 	emitAsset: EmitAsset;
@@ -84,6 +85,9 @@ export function createPluginDriver(
 
 		const context: PluginContext = {
 			watcher,
+			addWatchFile(id: string) {
+				graph.watchFiles.push(resolve(id));
+			},
 			cache: cacheInstance,
 			isExternal(id: string, parentId: string, isResolved = false) {
 				return graph.isExternal(id, parentId, isResolved);

src/utils/transform.ts

@@ -43,7 +43,7 @@ export default function transform(
 
 	function transformReducer(code: string, result: any, plugin: Plugin) {
 		// track which plugins use the custom this.cache to opt-out of transform caching
-		if (trackedPluginCache.used) customTransformCache = true;
+		if (!customTransformCache && trackedPluginCache.used) customTransformCache = true;
 		if (customTransformCache) {
 			if (result && Array.isArray(result.dependencies)) {
 				for (const dep of result.dependencies) {
@@ -103,13 +103,14 @@ export default function transform(
 			[curSource, id],
 			transformReducer,
 			(pluginContext, plugin) => {
-				trackedPluginCache = trackPluginCache(pluginContext.cache);
+				if (plugin.cacheKey) customTransformCache = true;
+				else trackedPluginCache = trackPluginCache(pluginContext.cache);
 
 				let emitAsset: EmitAsset;
 				({ assets, emitAsset } = createTransformEmitAsset(graph.assetsById, baseEmitAsset));
 				return {
 					...pluginContext,
-					cache: trackedPluginCache.cache,
+					cache: trackedPluginCache ? trackedPluginCache.cache : pluginContext.cache,
 					warn(warning: RollupWarning | string, pos?: { line: number; column: number }) {
 						if (typeof warning === 'string') warning = { message: warning };
 						if (pos) augmentCodeLocation(warning, pos, curSource, id);

test/watch/index.js

@@ -1,6 +1,7 @@
 const assert = require('assert');
 const sander = require('sander');
 const rollup = require('../../dist/rollup');
+const path = require('path');
 
 const cwd = process.cwd();
 
@@ -354,6 +355,51 @@ describe('rollup.watch', () => {
 				});
 		});
 
+		it('supports transform cache opt-out via cacheKey and custom watchFiles', () => {
+			return sander
+				.copydir('test/watch/samples/transform-dependencies')
+				.to('test/_tmp/input')
+				.then(() => {
+					const watcher = rollup.watch({
+						input: 'test/_tmp/input/main.js',
+						output: {
+							file: 'test/_tmp/output/bundle.js',
+							format: 'cjs'
+						},
+						plugins: [
+							{
+								cacheKey: 'asdf',
+								transform(code) {
+									this.addWatchFile('test/_tmp/input/asdf');
+									const text = sander.readFileSync('test/_tmp/input/asdf').toString();
+									return `export default "${text}"`;
+								}
+							}
+						],
+						watch: { chokidar }
+					});
+
+					return sequence(watcher, [
+						'START',
+						'BUNDLE_START',
+						'BUNDLE_END',
+						'END',
+						() => {
+							assert.equal(run('../_tmp/output/bundle.js'), 'asdf');
+							sander.unlinkSync('test/_tmp/input/asdf');
+							sander.writeFileSync('test/_tmp/input/asdf', 'next');
+						},
+						'START',
+						'BUNDLE_START',
+						'BUNDLE_END',
+						'END',
+						() => {
+							assert.equal(run('../_tmp/output/bundle.js'), 'next');
+						}
+					]);
+				});
+		});
+
 		it('throws if transform dependency doesnt exist', () => {
 			return sander
 				.copydir('test/watch/samples/transform-dependencies')