config - need to watch parent folder to detect ADD and DELETE of config

src/vs/base/node/config.ts

@@ -6,6 +6,7 @@
 'use strict';
 
 import * as fs from 'fs';
+import * as path from 'path';
 import * as objects from 'vs/base/common/objects';
 import {IDisposable, dispose, toDisposable} from 'vs/base/common/lifecycle';
 import Event, {Emitter} from 'vs/base/common/event';
@@ -113,7 +114,15 @@ export class ConfigWatcher<T> implements IConfigWatcher<T>, IDisposable {
 
 	private registerWatcher(): void {
 
-		// Support for watching symlinks
+		// Watch the parent of the path so that we detect ADD and DELETES
+		const parentFolder = path.dirname(this._path);
+		fs.exists(parentFolder, exists => {
+			if (exists) {
+				this.watch(parentFolder);
+			}
+		});
+
+		// Check if the path is a symlink and watch its target if so
 		fs.lstat(this._path, (err, stat) => {
 			if (err || stat.isDirectory()) {
 				return; // path is not a valid file
@@ -129,11 +138,6 @@ export class ConfigWatcher<T> implements IConfigWatcher<T>, IDisposable {
 					this.watch(realPath);
 				});
 			}
-
-			// We found a normal file
-			else {
-				this.watch(this._path);
-			}
 		});
 	}
 
@@ -142,13 +146,17 @@ export class ConfigWatcher<T> implements IConfigWatcher<T>, IDisposable {
 			return; // avoid watchers that will never get disposed by checking for being disposed
 		}
 
-		const watcher = fs.watch(path);
-		watcher.on('change', () => this.onConfigFileChange());
+		try {
+			const watcher = fs.watch(path);
+			watcher.on('change', () => this.onConfigFileChange());
 
-		this.disposables.push(toDisposable(() => {
-			watcher.removeAllListeners();
-			watcher.close();
-		}));
+			this.disposables.push(toDisposable(() => {
+				watcher.removeAllListeners();
+				watcher.close();
+			}));
+		} catch (error) {
+			console.warn(`Failed to watch ${path} for configuration changes (${error.toString()})`);
+		}
 	}
 
 	private onConfigFileChange(): void {

src/vs/base/test/node/config.test.ts

@@ -111,6 +111,50 @@ suite('Config', () => {
 		});
 	});
 
+	test('watching also works when file created later', function (done: () => void) {
+		testFile((testFile, cleanUp) => {
+			let watcher = new ConfigWatcher<{ foo: string; }>(testFile);
+
+			fs.writeFileSync(testFile, '// my comment\n{ "foo": "bar" }');
+
+			setTimeout(function () {
+				fs.writeFileSync(testFile, '// my comment\n{ "foo": "changed" }');
+			}, 50);
+
+			watcher.onDidUpdateConfiguration(event => {
+				assert.ok(event);
+				assert.equal(event.config.foo, 'changed');
+				assert.equal(watcher.getValue('foo'), 'changed');
+
+				watcher.dispose();
+
+				cleanUp(done);
+			});
+
+		});
+	});
+
+	test('watching detects the config file getting deleted', function (done: () => void) {
+		testFile((testFile, cleanUp) => {
+			fs.writeFileSync(testFile, '// my comment\n{ "foo": "bar" }');
+
+			let watcher = new ConfigWatcher<{ foo: string; }>(testFile);
+
+			setTimeout(function () {
+				fs.unlinkSync(testFile);
+			}, 50);
+
+			watcher.onDidUpdateConfiguration(event => {
+				assert.ok(event);
+
+				watcher.dispose();
+
+				cleanUp(done);
+			});
+
+		});
+	});
+
 	test('reload', function (done: () => void) {
 		testFile((testFile, cleanUp) => {
 			fs.writeFileSync(testFile, '// my comment\n{ "foo": "bar" }');