From 95c38f754dfbbb687aa461abe3598aac4389356b Mon Sep 17 00:00:00 2001
From: Rebecca Stambler <rstambler@golang.org>
Date: Tue, 28 Jan 2020 23:12:38 -0500
Subject: [PATCH] restart language server automatically instead of asking user
 to reload

---
 src/goInstallTools.ts   |  8 ++++----
 src/goLanguageServer.ts | 30 ++++++++++++++++++++----------
 src/goModules.ts        |  6 ------
 3 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/src/goInstallTools.ts b/src/goInstallTools.ts
index 93b42e9a17..48a660a901 100644
--- a/src/goInstallTools.ts
+++ b/src/goInstallTools.ts
@@ -13,7 +13,6 @@ import { getLanguageServerToolPath } from './goLanguageServer';
 import { envPath, getToolFromToolPath } from './goPath';
 import { hideGoStatus, outputChannel, showGoStatus } from './goStatus';
 import {
-	containsString,
 	containsTool,
 	disableModulesForWildcard,
 	getConfiguredTools,
@@ -205,6 +204,10 @@ export function installTools(missing: Tool[], goVersion: GoVersion): Promise<voi
 								resolve([...sofar, failureReason]);
 							} else {
 								outputChannel.appendLine('Installing ' + getImportPath(tool, goVersion) + ' SUCCEEDED');
+								// If a new version of gopls has been installed, restart the language server.
+								if (tool.name === 'gopls') {
+									vscode.commands.executeCommand('go.languageserver.restart');
+								}
 								resolve([...sofar, null]);
 							}
 						};
@@ -271,9 +274,6 @@ export function installTools(missing: Tool[], goVersion: GoVersion): Promise<voi
 			outputChannel.appendLine(''); // Blank line for spacing
 			const failures = res.filter((x) => x != null);
 			if (failures.length === 0) {
-				if (containsString(missing, 'go-langserver') || containsString(missing, 'gopls')) {
-					outputChannel.appendLine('Reload VS Code window to use the Go language server');
-				}
 				outputChannel.appendLine('All tools successfully installed. You are ready to Go :).');
 				return;
 			}
diff --git a/src/goLanguageServer.ts b/src/goLanguageServer.ts
index e7e7b4530a..a8a15bdf12 100644
--- a/src/goLanguageServer.ts
+++ b/src/goLanguageServer.ts
@@ -234,22 +234,31 @@ function watchLanguageServerConfiguration(e: vscode.ConfigurationChangeEvent) {
 	}
 
 	const config = parseLanguageServerConfig();
+	let shouldRestartServer: boolean;
 	let reloadMessage: string;
 
-	// If the user has disabled or enabled the language server.
+	// If the user enabled the language server, we just need to start it.
 	if (e.affectsConfiguration('go.useLanguageServer')) {
 		if (config.enabled) {
-			reloadMessage = 'Reload VS Code window to enable the use of language server';
+			shouldRestartServer = true;
 		} else {
-			reloadMessage = 'Reload VS Code window to disable the use of language server';
+			// If the user has disabled the language server, we will need to
+			// reactivate the extension to register the correct providers,
+			// so suggest a full VS Code reload.
+			reloadMessage = 'Reload VS Code window to disable the use of language server.';
 		}
 	}
 
-	if (
-		e.affectsConfiguration('go.languageServerFlags') ||
-		e.affectsConfiguration('go.languageServerExperimentalFeatures')
-	) {
-		reloadMessage = 'Reload VS Code window for the changes in language server settings to take effect';
+	// If the flags to the language server have changed,
+	// all that's necessary is a server restart.
+	if (e.affectsConfiguration('go.languageServerFlags')) {
+		// TODO(rstambler): This should be doable by creating a new client.
+		reloadMessage = 'Reload VS Code window for changes in the language server flags to take effect.';
+	}
+	// If the features provided by the language server have changed,
+	// the extensions requires a full reactivation.
+	if (e.affectsConfiguration('go.languageServerExperimentalFeatures')) {
+		reloadMessage = 'Reload VS Code window for the changes in language server features to take effect.';
 	}
 
 	// If there was a change in the configuration of the language server,
@@ -260,6 +269,8 @@ function watchLanguageServerConfiguration(e: vscode.ConfigurationChangeEvent) {
 				vscode.commands.executeCommand('workbench.action.reloadWindow');
 			}
 		});
+	} else if (shouldRestartServer) {
+		vscode.commands.executeCommand('go.languageserver.restart');
 	}
 }
 
@@ -329,13 +340,12 @@ export function getLanguageServerToolPath(): string {
 	// Only gopls and go-langserver are supported.
 	if (languageServerOfChoice !== 'gopls' && languageServerOfChoice !== 'go-langserver') {
 		vscode.window.showErrorMessage(
-			`Cannot find the language server ${languageServerOfChoice}. Please install it and reload this VS Code window`
+			`Cannot find the language server ${languageServerOfChoice}. Please install it.`
 		);
 		return;
 	}
 	// Otherwise, prompt the user to install the language server.
 	promptForMissingTool(languageServerOfChoice);
-	vscode.window.showInformationMessage('Reload VS Code window after installing the Go language server.');
 }
 
 function allFoldersHaveSameGopath(): boolean {
diff --git a/src/goModules.ts b/src/goModules.ts
index d50e75a10f..163dfacc50 100644
--- a/src/goModules.ts
+++ b/src/goModules.ts
@@ -135,12 +135,6 @@ export async function promptToUpdateToolForModules(
 						if (goConfig.inspect('useLanguageServer').workspaceFolderValue === false) {
 							goConfig.update('useLanguageServer', true, vscode.ConfigurationTarget.WorkspaceFolder);
 						}
-						const reloadMsg = 'Reload VS Code window to enable the use of Go language server';
-						vscode.window.showInformationMessage(reloadMsg, 'Reload').then((selectedForReload) => {
-							if (selectedForReload === 'Reload') {
-								vscode.commands.executeCommand('workbench.action.reloadWindow');
-							}
-						});
 					}
 				});
 			}