Fixes race conditions of writing and reading settings from multiple windows

src/vs/code/electron-main/app.ts

@@ -89,6 +89,7 @@ import { getRemoteAuthority } from 'vs/platform/remote/common/remoteHosts';
 import { ISignService } from 'vs/platform/sign/common/sign';
 import { IExternalTerminalMainService } from 'vs/platform/externalTerminal/common/externalTerminal';
 import { LinuxExternalTerminalService, MacExternalTerminalService, WindowsExternalTerminalService } from 'vs/platform/externalTerminal/node/externalTerminalService';
+import { UserConfigurationFileServiceId, UserConfigurationFileService } from 'vs/platform/configuration/common/userConfigurationFileService';
 
 /**
  * The main VS Code application. There will only ever be one instance,
@@ -588,6 +589,9 @@ export class CodeApplication extends Disposable {
 		const launchChannel = ProxyChannel.fromService(accessor.get(ILaunchMainService), { disableMarshalling: true });
 		this.mainProcessNodeIpcServer.registerChannel('launch', launchChannel);
 
+		// Configuration
+		mainProcessElectronServer.registerChannel(UserConfigurationFileServiceId, ProxyChannel.fromService(new UserConfigurationFileService(this.environmentMainService, this.fileService, this.logService)));
+
 		// Update
 		const updateChannel = new UpdateChannel(accessor.get(IUpdateService));
 		mainProcessElectronServer.registerChannel('update', updateChannel);

src/vs/workbench/services/configuration/browser/configuration.ts

@@ -7,7 +7,7 @@ import { URI } from 'vs/base/common/uri';
 import { Event, Emitter } from 'vs/base/common/event';
 import * as errors from 'vs/base/common/errors';
 import { Disposable, IDisposable, dispose, toDisposable, MutableDisposable, combinedDisposable, DisposableStore } from 'vs/base/common/lifecycle';
-import { RunOnceScheduler } from 'vs/base/common/async';
+import { RunOnceScheduler, timeout } from 'vs/base/common/async';
 import { FileChangeType, FileChangesEvent, IFileService, whenProviderRegistered, FileOperationError, FileOperationResult } from 'vs/platform/files/common/files';
 import { ConfigurationModel, ConfigurationModelParser, ConfigurationParseOptions, UserSettings } from 'vs/platform/configuration/common/configurationModels';
 import { WorkspaceConfigurationModelParser, StandaloneConfigurationModelParser } from 'vs/workbench/services/configuration/common/configurationModels';
@@ -23,6 +23,7 @@ import { hash } from 'vs/base/common/hash';
 import { IUriIdentityService } from 'vs/workbench/services/uriIdentity/common/uriIdentity';
 import { ILogService } from 'vs/platform/log/common/log';
 import { IStringDictionary } from 'vs/base/common/collections';
+import { ResourceMap } from 'vs/base/common/map';
 
 export class UserConfiguration extends Disposable {
 
@@ -93,6 +94,10 @@ class FileServiceBasedConfiguration extends Disposable {
 	private readonly _onDidChange: Emitter<void> = this._register(new Emitter<void>());
 	readonly onDidChange: Event<void> = this._onDidChange.event;
 
+	private readonly resourcesContentMap = new ResourceMap<boolean>(uri => this.uriIdentityService.extUri.getComparisonKey(uri));
+
+	private disposed: boolean = false;
+
 	constructor(
 		name: string,
 		private readonly settingsResource: URI,
@@ -116,19 +121,32 @@ class FileServiceBasedConfiguration extends Disposable {
 		this._cache = new ConfigurationModel();
 
 		this._register(Event.debounce(Event.filter(this.fileService.onDidFilesChange, e => this.handleFileEvents(e)), () => undefined, 100)(() => this._onDidChange.fire()));
+		this._register(toDisposable(() => this.disposed = true));
 	}
 
 	async resolveContents(): Promise<[string | undefined, [string, string | undefined][]]> {
 
 		const resolveContents = async (resources: URI[]): Promise<(string | undefined)[]> => {
 			return Promise.all(resources.map(async resource => {
 				try {
-					const content = (await this.fileService.readFile(resource, { atomic: true })).value.toString();
+					let content = (await this.fileService.readFile(resource, { atomic: true })).value.toString();
+
+					// If file is empty and had content before then file would have been truncated by node because of parallel writes from other windows
+					// To prevent such case, retry reading the file in 20ms intervals until file has content or max 5 trials or disposed.
+					// https://github.com/microsoft/vscode/issues/115740 https://github.com/microsoft/vscode/issues/125970
+					for (let trial = 1; !content && this.resourcesContentMap.get(resource) && !this.disposed && trial <= 5; trial++) {
+						await timeout(20);
+						this.logService.debug(`Retry (${trial}): Reading the configuration file`, resource.toString());
+						content = (await this.fileService.readFile(resource)).value.toString();
+					}
+
+					this.resourcesContentMap.set(resource, !!content);
 					if (!content) {
 						this.logService.debug(`Configuration file '${resource.toString()}' is empty`);
 					}
 					return content;
 				} catch (error) {
+					this.resourcesContentMap.delete(resource);
 					this.logService.trace(`Error while resolving configuration file '${resource.toString()}': ${errors.getErrorMessage(error)}`);
 					if ((<FileOperationError>error).fileOperationResult !== FileOperationResult.FILE_NOT_FOUND
 						&& (<FileOperationError>error).fileOperationResult !== FileOperationResult.FILE_NOT_DIRECTORY) {

src/vs/workbench/services/configuration/electron-sandbox/userConfigurationFileService.ts

@@ -0,0 +1,9 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import { registerMainProcessRemoteService } from 'vs/platform/ipc/electron-sandbox/services';
+import { IUserConfigurationFileService, UserConfigurationFileServiceId } from 'vs/platform/configuration/common/userConfigurationFileService';
+
+registerMainProcessRemoteService(IUserConfigurationFileService, UserConfigurationFileServiceId);

src/vs/workbench/workbench.common.main.ts

@@ -124,9 +124,7 @@ import { OpenerService } from 'vs/editor/browser/services/openerService';
 import { IOpenerService } from 'vs/platform/opener/common/opener';
 import { IgnoredExtensionsManagementService, IIgnoredExtensionsManagementService } from 'vs/platform/userDataSync/common/ignoredExtensions';
 import { ExtensionsStorageSyncService, IExtensionsStorageSyncService } from 'vs/platform/userDataSync/common/extensionsStorageSync';
-import { IUserConfigurationFileService, UserConfigurationFileService } from 'vs/platform/configuration/common/userConfigurationFileService';
 
-registerSingleton(IUserConfigurationFileService, UserConfigurationFileService);
 registerSingleton(IIgnoredExtensionsManagementService, IgnoredExtensionsManagementService);
 registerSingleton(IGlobalExtensionEnablementService, GlobalExtensionEnablementService);
 registerSingleton(IExtensionsStorageSyncService, ExtensionsStorageSyncService);

src/vs/workbench/workbench.sandbox.main.ts

@@ -68,6 +68,7 @@ import 'vs/platform/diagnostics/electron-sandbox/diagnosticsService';
 import 'vs/platform/checksum/electron-sandbox/checksumService';
 import 'vs/platform/telemetry/electron-sandbox/customEndpointTelemetryService';
 import 'vs/workbench/services/files/electron-sandbox/elevatedFileService';
+import 'vs/workbench/services/configuration/electron-sandbox/userConfigurationFileService';
 
 import { registerSingleton } from 'vs/platform/instantiation/common/extensions';
 import { IUserDataInitializationService, UserDataInitializationService } from 'vs/workbench/services/userData/browser/userDataInit';

src/vs/workbench/workbench.web.main.ts

@@ -87,7 +87,9 @@ import { TitlebarPart } from 'vs/workbench/browser/parts/titlebar/titlebarPart';
 import { ITimerService, TimerService } from 'vs/workbench/services/timer/browser/timerService';
 import { IConfigurationResolverService } from 'vs/workbench/services/configurationResolver/common/configurationResolver';
 import { ConfigurationResolverService } from 'vs/workbench/services/configurationResolver/browser/configurationResolverService';
+import { IUserConfigurationFileService, UserConfigurationFileService } from 'vs/platform/configuration/common/userConfigurationFileService';
 
+registerSingleton(IUserConfigurationFileService, UserConfigurationFileService);
 registerSingleton(IWorkbenchExtensionManagementService, ExtensionManagementService);
 registerSingleton(IAccessibilityService, AccessibilityService, true);
 registerSingleton(IContextMenuService, ContextMenuService);