Require opt-in to AVA 5's watcher, remove chokidar from dependencies

docs/recipes/watch-mode.md

@@ -4,6 +4,15 @@ Translations: [Français](https://github.com/avajs/ava-docs/blob/main/fr_FR/docs
 
 AVA comes with an intelligent watch mode. It watches for files to change and runs just those tests that are affected.
 
+AVA 6 is introducing a new watch mode that relies on recurse file watching in Node.js. To use the old watch mode, set the `watcher` configuration to `ava5+chokidar` and install [`chokidar`] alongside AVA:
+
+`ava.config.mjs`:
+```js
+export default {
+	watcher: 'ava5+chokidar'
+}
+```
+
 ## Running tests with watch mode enabled
 
 You can enable watch mode using the `--watch` or `-w` flags:
@@ -16,7 +25,9 @@ Please note that integrated debugging and the TAP reporter are unavailable when
 
 ## Requirements
 
-AVA uses [`chokidar`] as the file watcher. Note that even if you see warnings about optional dependencies failing during install, it will still work fine. Please refer to the *[Install Troubleshooting]* section of `chokidar` documentation for how to resolve the installation problems with chokidar.
+AVA 5 uses [`chokidar`] as the file watcher. Note that even if you see warnings about optional dependencies failing during install, it will still work fine. Please refer to the *[Install Troubleshooting]* section of `chokidar` documentation for how to resolve the installation problems with chokidar.
+
+The same applies with AVA 6 when using the `ava5+chokidar` watcher. However you'll need to install `chokidar` separately.
 
 ## Ignoring changes
 
@@ -30,7 +41,9 @@ If your tests write to disk they may trigger the watcher to rerun your tests. Co
 
 AVA tracks which source files your test files depend on. If you change such a dependency only the test file that depends on it will be rerun. AVA will rerun all tests if it cannot determine which test file depends on the changed source file.
 
-Dependency tracking works for required modules. Custom extensions and transpilers are supported, provided you [added them in your `package.json` or `ava.config.*` file][config], and not from inside your test file. Files accessed using the `fs` module are not tracked.
+AVA 5 (and the `ava5+chokidar` watcher in AVA 6) spies on `require()` calls to track dependencies. Custom extensions and transpilers are supported, provided you [added them in your `package.json` or `ava.config.*` file][config], and not from inside your test file.
+
+Files accessed using the `fs` module are not tracked.
 
 ## Watch mode and the `.only` modifier
 

lib/watcher.js → lib/ava5-watcher.js

@@ -169,11 +169,16 @@ export default class Watcher {
 	trackTestDependencies(api) {
 		api.on('run', plan => {
 			plan.status.on('stateChange', evt => {
-				if (evt.type !== 'dependencies') {
+				let dependencies;
+				if (evt.type === 'dependencies') {
+					dependencies = evt.dependencies;
+				} else if (evt.type === 'accessed-snapshots') {
+					dependencies = [evt.filename];
+				} else {
 					return;
 				}
 
-				const dependencies = evt.dependencies.filter(filePath => {
+				dependencies = dependencies.filter(filePath => {
 					const {isIgnoredByWatcher} = classify(filePath, this.globs);
 					return !isIgnoredByWatcher;
 				});

lib/cli.js

@@ -25,7 +25,6 @@ import pkg from './pkg.cjs';
 import providerManager from './provider-manager.js';
 import DefaultReporter from './reporters/default.js';
 import TapReporter from './reporters/tap.js';
-import Watcher from './watcher.js';
 
 function exit(message) {
 	console.error(`\n  ${chalk.red(figures.cross)} ${message}`);
@@ -415,6 +414,7 @@ export default async function loadCli() { // eslint-disable-line complexity
 		concurrency: combined.concurrency || 0,
 		workerThreads: combined.workerThreads !== false,
 		debug,
+		enableAva5DependencyTracking: argv.watch && conf.watcher === 'ava5+chokidar',
 		environmentVariables,
 		experiments,
 		extensions,
@@ -476,15 +476,24 @@ export default async function loadCli() { // eslint-disable-line complexity
 	});
 
 	if (argv.watch) {
-		const watcher = new Watcher({
-			api,
-			filter,
-			globs,
-			projectDir,
-			providers,
-			reporter,
-		});
-		watcher.observeStdin(process.stdin);
+		if (Object.hasOwn(conf, 'watcher')) {
+			if (conf.watcher === 'ava5+chokidar') {
+				const {default: Watcher} = await import('./ava5-watcher.js');
+				const watcher = new Watcher({
+					api,
+					filter,
+					globs,
+					projectDir,
+					providers,
+					reporter,
+				});
+				watcher.observeStdin(process.stdin);
+			} else {
+				exit('The "watcher" option must be set to "ava5+chokidar"');
+			}
+		} else {
+			exit('TODO');
+		}
 	} else {
 		let debugWithoutSpecificFile = false;
 		api.on('run', plan => {

lib/runner.js

@@ -209,7 +209,7 @@ export default class Runner extends Emittery {
 			updating: this.updateSnapshots,
 		});
 		if (snapshots.snapPath !== undefined) {
-			this.emit('dependency', snapshots.snapPath);
+			this.emit('accessed-snapshots', snapshots.snapPath);
 		}
 
 		this._snapshots = snapshots;

lib/worker/base.js

@@ -14,8 +14,9 @@ import providerManager from '../provider-manager.js';
 import Runner from '../runner.js';
 import serializeError from '../serialize-error.js';
 
+// TODO: Delete along with ava5+chokidar watcher.
+import dependencyTracking from './ava5-dependency-tracker.js';
 import channel from './channel.cjs';
-import dependencyTracking from './dependency-tracker.js';
 import lineNumberSelection from './line-numbers.js';
 import {set as setOptions} from './options.cjs';
 import {flags, refs, sharedWorkerTeardowns} from './state.cjs';
@@ -99,7 +100,11 @@ const run = async options => {
 		runner.interrupt();
 	});
 
-	runner.on('dependency', dependencyTracking.track);
+	runner.on('accessed-snapshots', filename => channel.send({type: 'accessed-snapshots', filename}));
+	if (options.enableAva5DependencyTracking) {
+		runner.on('dependency', dependencyTracking.track);
+	}
+
 	runner.on('stateChange', state => channel.send(state));
 
 	runner.on('error', error => {
@@ -229,9 +234,11 @@ const run = async options => {
 			}
 		}
 
-		// Install dependency tracker after the require configuration has been evaluated
-		// to make sure we also track dependencies with custom require hooks
-		dependencyTracking.install(require.extensions, testPath);
+		if (options.enableAva5DependencyTracking) {
+			// Install dependency tracker after the require configuration has been evaluated
+			// to make sure we also track dependencies with custom require hooks
+			dependencyTracking.install(require.extensions, testPath);
+		}
 
 		if (options.debug && options.debug.port !== undefined && options.debug.host !== undefined) {
 			// If an inspector was active when the main process started, and is

package.json

@@ -89,7 +89,6 @@
 		"callsites": "^4.0.0",
 		"cbor": "^8.1.0",
 		"chalk": "^5.2.0",
-		"chokidar": "^3.5.3",
 		"chunkd": "^2.0.1",
 		"ci-info": "^3.8.0",
 		"ci-parallel-vars": "^1.0.1",
@@ -142,11 +141,15 @@
 		"zen-observable": "^0.10.0"
 	},
 	"peerDependencies": {
-		"@ava/typescript": "*"
+		"@ava/typescript": "*",
+		"chokidar": "^3.5.3"
 	},
 	"peerDependenciesMeta": {
 		"@ava/typescript": {
 			"optional": true
+		},
+		"chokidar": {
+			"optional": true
 		}
 	},
 	"volta": {

test-tap/api.js

@@ -418,40 +418,6 @@ for (const opt of options) {
 			});
 	});
 
-	test(`emits dependencies for test files - workerThreads: ${opt.workerThreads}`, async t => {
-		t.plan(8);
-
-		const api = await apiCreator({
-			...opt,
-			files: ['test-tap/fixture/with-dependencies/*test*.cjs'],
-			require: [path.resolve('test-tap/fixture/with-dependencies/require-custom.cjs')],
-		});
-
-		const testFiles = new Set([
-			path.resolve('test-tap/fixture/with-dependencies/no-tests.cjs'),
-			path.resolve('test-tap/fixture/with-dependencies/test.cjs'),
-			path.resolve('test-tap/fixture/with-dependencies/test-failure.cjs'),
-			path.resolve('test-tap/fixture/with-dependencies/test-uncaught-exception.cjs'),
-		]);
-
-		const sourceFiles = [
-			path.resolve('test-tap/fixture/with-dependencies/dep-1.js'),
-			path.resolve('test-tap/fixture/with-dependencies/dep-2.js'),
-			path.resolve('test-tap/fixture/with-dependencies/dep-3.custom'),
-		];
-
-		api.on('run', plan => {
-			plan.status.on('stateChange', evt => {
-				if (evt.type === 'dependencies') {
-					t.ok(testFiles.has(evt.testFile));
-					t.strictSame(evt.dependencies.filter(dep => !dep.endsWith('.snap')).slice(-3), sourceFiles);
-				}
-			});
-		});
-
-		return api.run();
-	});
-
 	test(`verify test count - workerThreads: ${opt.workerThreads}`, async t => {
 		t.plan(4);