From 466e69b8edc25cad61d2aff295a4573bbd9eda66 Mon Sep 17 00:00:00 2001
From: Benjamin Pasero <benjpas@microsoft.com>
Date: Tue, 19 Mar 2019 09:09:30 +0100
Subject: [PATCH] files2 - always trigger activation event for fs provider,
 even if already registered

---
 .../services/files2/browser/fileService2.ts          | 12 ++++++++----
 .../files2/test/browser/fileService2.test.ts         |  9 ++++++++-
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/vs/workbench/services/files2/browser/fileService2.ts b/src/vs/workbench/services/files2/browser/fileService2.ts
index eec59d16654..39dd466abe0 100644
--- a/src/vs/workbench/services/files2/browser/fileService2.ts
+++ b/src/vs/workbench/services/files2/browser/fileService2.ts
@@ -69,12 +69,10 @@ export class FileService2 extends Disposable implements IFileService {
 	}
 
 	activateProvider(scheme: string): Promise<void> {
-		if (this.provider.has(scheme)) {
-			return Promise.resolve(); // provider is already here! TODO@ben should we still activate by event but not wait for it?
-		}
 
+		// Emit an event that we are about to activate a provider with the given scheme.
+		// Listeners can participate in the activation by registering a provider for it.
 		const joiners: Promise<void>[] = [];
-
 		this._onWillActivateFileSystemProvider.fire({
 			scheme,
 			join(promise) {
@@ -84,6 +82,12 @@ export class FileService2 extends Disposable implements IFileService {
 			},
 		});
 
+		if (this.provider.has(scheme)) {
+			return Promise.resolve(); // provider is already here so we can return directly
+		}
+
+		// If the provider is not yet there, make sure to join on the listeners assuming
+		// that it takes a bit longer to register the file system provider.
 		return Promise.all(joiners).then(() => undefined);
 	}
 
diff --git a/src/vs/workbench/services/files2/test/browser/fileService2.test.ts b/src/vs/workbench/services/files2/test/browser/fileService2.test.ts
index 657594f1972..29a63567a3e 100644
--- a/src/vs/workbench/services/files2/test/browser/fileService2.test.ts
+++ b/src/vs/workbench/services/files2/test/browser/fileService2.test.ts
@@ -23,8 +23,11 @@ suite('File Service 2', () => {
 		});
 
 		let registrationDisposable: IDisposable;
+		let callCount = 0;
 		service.onWillActivateFileSystemProvider(e => {
-			if (e.scheme === 'test') {
+			callCount++;
+
+			if (e.scheme === 'test' && callCount === 1) {
 				e.join(new Promise(resolve => {
 					registrationDisposable = service.registerProvider('test', new NullFileSystemProvider());
 
@@ -40,6 +43,10 @@ suite('File Service 2', () => {
 		assert.equal(registrations.length, 1);
 		assert.equal(registrations[0].scheme, 'test');
 		assert.equal(registrations[0].added, true);
+		assert.ok(registrationDisposable);
+
+		await service.activateProvider('test');
+		assert.equal(callCount, 2); // activation is called again
 
 		registrationDisposable.dispose();