Install tools with modules enabled

src/goInstallTools.ts

@@ -6,11 +6,15 @@
 'use strict';
 
 import vscode = require('vscode');
+import os = require('os');
 import fs = require('fs');
 import path = require('path');
 import cp = require('child_process');
 import { showGoStatus, hideGoStatus, outputChannel } from './goStatus';
-import { getBinPath, getToolsGopath, getGoVersion, SemVersion, isVendorSupported, getCurrentGoPath, resolvePath } from './util';
+import {
+	getBinPath, getToolsGopath, getGoVersion, SemVersion, isVendorSupported, getCurrentGoPath,
+	resolvePath, isBelow, rmdirRecursive, getTempFilePath
+} from './util';
 import { goLiveErrorsEnabled } from './goLiveErrors';
 import { getToolFromToolPath, envPath } from './goPath';
 
@@ -40,7 +44,7 @@ const allToolsWithImportPaths: { [key: string]: string } = {
 	'golangci-lint': 'github.com/golangci/golangci-lint/cmd/golangci-lint',
 	'revive': 'github.com/mgechev/revive',
 	'go-langserver': 'github.com/sourcegraph/go-langserver',
-	'gopls': 'golang.org/x/tools/cmd/gopls',
+	'gopls': 'golang.org/x/tools/gopls',
 	'dlv': 'github.com/go-delve/delve/cmd/dlv',
 	'fillstruct': 'github.com/davidrjenni/reftools/cmd/fillstruct',
 	'godoctor': 'github.com/godoctor/godoctor',
@@ -311,7 +315,13 @@ export function installTools(missing: string[], goVersion: SemVersion): Promise<
 		return;
 	}
 
-	envForTools['GO111MODULE'] = 'off';
+	// If the user is on Go >= 1.11, tools should be installed with modules enabled.
+	// This ensures that users get the latest tagged version, rather than master,
+	// which may be unstable.
+	let modulesOff = false;
+	if (isBelow(goVersion, 1, 11)) {
+		modulesOff = true;
+	}
 
 	outputChannel.show();
 	outputChannel.clear();
@@ -322,8 +332,23 @@ export function installTools(missing: string[], goVersion: SemVersion): Promise<
 
 	outputChannel.appendLine(''); // Blank line for spacing.
 
+	// Install tools in a temporary directory, to avoid altering go.mod files.
+	const toolsTmpDir = getTempFilePath('go-tools');
+	if (!fs.existsSync(toolsTmpDir)) {
+		fs.mkdirSync(toolsTmpDir);
+	}
+
 	return missing.reduce((res: Promise<string[]>, tool: string) => {
-		return res.then(sofar => new Promise<string[]>((resolve, reject) => {
+		// Disable modules for staticcheck and gotests,
+		// which are installed with the "..." wildcard.
+		// TODO: ... will be supported in Go 1.13, so enable these tools to use modules then.
+		if (modulesOff || tool === 'staticcheck' || tool === 'gotests') {
+			envForTools['GO111MODULE'] = 'off';
+		} else {
+			envForTools['GO111MODULE'] = 'on';
+		}
+
+		return res.then(sofar => new Promise<string[]>((resolve) => {
 			const callback = (err: Error, stdout: string, stderr: string) => {
 				if (err) {
 					outputChannel.appendLine('Installing ' + getToolImportPath(tool, goVersion) + ' FAILED');
@@ -369,18 +394,26 @@ export function installTools(missing: string[], goVersion: SemVersion): Promise<
 					resolve([...sofar, null]);
 					return;
 				}
-				const args = ['get', '-u', '-v'];
+				const args = ['get', '-v'];
+				// Only get tools at master if we are not using modules.
+				if (modulesOff) {
+					args.push('-u');
+				}
 				if (tool.endsWith('-gomod')) {
 					args.push('-d');
 				}
+				const opts = {
+					env: envForTools,
+					cwd: toolsTmpDir,
+				};
 				args.push(getToolImportPath(tool, goVersion));
-				cp.execFile(goRuntimePath, args, { env: envForTools }, (err, stdout, stderr) => {
+				cp.execFile(goRuntimePath, args, opts, (err, stdout, stderr) => {
 					if (stderr.indexOf('unexpected directory layout:') > -1) {
 						outputChannel.appendLine(`Installing ${tool} failed with error "unexpected directory layout". Retrying...`);
-						cp.execFile(goRuntimePath, args, { env: envForTools }, callback);
+						cp.execFile(goRuntimePath, args, opts, callback);
 					} else if (!err && tool.endsWith('-gomod')) {
 						const outputFile = path.join(toolsGopath, 'bin', process.platform === 'win32' ? `${tool}.exe` : tool);
-						cp.execFile(goRuntimePath, ['build', '-o', outputFile, getToolImportPath(tool, goVersion)], { env: envForTools }, callback);
+						cp.execFile(goRuntimePath, ['build', '-o', outputFile, getToolImportPath(tool, goVersion)], opts, callback);
 					} else {
 						callback(err, stdout, stderr);
 					}

src/util.ts

@@ -81,6 +81,10 @@ let vendorSupport: boolean = null;
 let telemtryReporter: TelemetryReporter;
 let toolsGopath: string;
 
+export function isBelow(goVersion: SemVersion, major: number, minor: number): boolean {
+	return goVersion && goVersion.major <= major && goVersion.minor < minor;
+}
+
 export function byteOffsetAt(document: vscode.TextDocument, position: vscode.Position): number {
 	const offset = document.offsetAt(position);
 	const text = document.getText();
@@ -847,7 +851,7 @@ export function makeMemoizedByteOffsetConverter(buffer: Buffer): (byteOffset: nu
 	};
 }
 
-function rmdirRecursive(dir: string) {
+export function rmdirRecursive(dir: string) {
 	if (fs.existsSync(dir)) {
 		fs.readdirSync(dir).forEach(file => {
 			const relPath = path.join(dir, file);