src: support custom formatTools with gopls enabled

gopls doesn't support all custom formatters, so wire through support
for custom formatting tools in the VS Code Go extension. The new default
formatTool is empty, since it's not used when configured with gopls.
If the user has gopls disabled, the default is goimports, as before.

The only thing is that I can't figure out how to make settings so they
can be enums or any other string, so custom formatters may look like
unrecognized settings.

Fixes golang#1238

Change-Id: I1694dc80e9d119cf83cb9a3a19dbdaef0cfac41f
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/295809
Trust: Rebecca Stambler <[email protected]>
Run-TryBot: Rebecca Stambler <[email protected]>
TryBot-Result: kokoro <[email protected]>
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>

docs/settings.md

@@ -233,9 +233,17 @@ Flags to pass to format tool (e.g. ["-s"]). Not applicable when using the langua
 ### `go.formatTool`
 
 Not applicable when using the language server. Choosing 'goimports', 'goreturns', or 'gofumports' will add missing imports and remove unused imports.<br/>
-Allowed Options: `gofmt`, `goimports`, `goreturns`, `goformat`, `gofumpt`, `gofumports`
+Allowed Options:
+
+* `default`: If the language server is enabled, format via the language server, which already supports gofmt, goimports, goreturns, and gofumpt. Otherwise, goimports.
+* `gofmt`: Formats the file according to the standard Go style.
+* `goimports`: Organizes imports and formats the file with gofmt.
+* `goformat`: Configurable gofmt, see https://github.com/mbenkmann/goformat.
+* `gofumpt`: Stricter version of gofmt, see https://github.com/mvdan/gofumpt.
+* `gofumports`: Applies gofumpt formatting and organizes imports.
 
-Default: `"goimports"`
+
+Default: `""`
 ### `go.generateTestsFlags`
 
 Additional command line flags to pass to `gotests` for generating tests.

package.json

@@ -1018,16 +1018,24 @@
         },
         "go.formatTool": {
           "type": "string",
-          "default": "goimports",
+          "default": "",
           "description": "Not applicable when using the language server. Choosing 'goimports', 'goreturns', or 'gofumports' will add missing imports and remove unused imports.",
           "scope": "resource",
           "enum": [
+            "default",
             "gofmt",
             "goimports",
-            "goreturns",
             "goformat",
             "gofumpt",
             "gofumports"
+          ],
+          "enumDescriptions": [
+            "If the language server is enabled, format via the language server, which already supports gofmt, goimports, goreturns, and gofumpt. Otherwise, goimports.",
+            "Formats the file according to the standard Go style.",
+            "Organizes imports and formats the file with gofmt.",
+            "Configurable gofmt, see https://github.com/mbenkmann/goformat.",
+            "Stricter version of gofmt, see https://github.com/mvdan/gofumpt.",
+            "Applies gofumpt formatting and organizes imports."
           ]
         },
         "go.formatFlags": {

src/goFormat.ts

@@ -27,20 +27,23 @@ export class GoDocumentFormattingEditProvider implements vscode.DocumentFormatti
 
 		const filename = document.fileName;
 		const goConfig = getGoConfig(document.uri);
-		const formatTool = goConfig['formatTool'] || 'goreturns';
 		const formatFlags = goConfig['formatFlags'].slice() || [];
 
-		// We ignore the -w flag that updates file on disk because that would break undo feature
+		// Ignore -w because we don't want to write directly to disk.
 		if (formatFlags.indexOf('-w') > -1) {
 			formatFlags.splice(formatFlags.indexOf('-w'), 1);
 		}
 
-		// Fix for https://github.com/Microsoft/vscode-go/issues/613 and https://github.com/Microsoft/vscode-go/issues/630
+		const formatTool = getFormatTool(goConfig);
+
+		// Handle issues:
+		//  https://github.com/Microsoft/vscode-go/issues/613
+		//  https://github.com/Microsoft/vscode-go/issues/630
 		if (formatTool === 'goimports' || formatTool === 'goreturns' || formatTool === 'gofumports') {
 			formatFlags.push('-srcdir', filename);
 		}
 
-		// Since goformat supports the style flag, set tabsize if user has not passed any flags
+		// Since goformat supports the style flag, set tabsize if the user hasn't.
 		if (formatTool === 'goformat' && formatFlags.length === 0 && options.insertSpaces) {
 			formatFlags.push('-style=indent=' + options.tabSize);
 		}
@@ -111,3 +114,30 @@ export class GoDocumentFormattingEditProvider implements vscode.DocumentFormatti
 		});
 	}
 }
+
+export function usingCustomFormatTool(goConfig: { [key: string]: any }): boolean {
+	const formatTool = getFormatTool(goConfig);
+	switch (formatTool) {
+		case 'goreturns':
+			return false;
+		case 'goimports':
+			return false;
+		case 'gofmt':
+			return false;
+		case 'gofumpt':
+			// TODO(rstambler): Prompt to configure setting in gopls.
+			return false;
+		case 'gofumports':
+			// TODO(rstambler): Prompt to configure setting in gopls.
+			return false;
+		default:
+			return true;
+	}
+}
+
+export function getFormatTool(goConfig: { [key: string]: any }): string {
+	if (goConfig['formatTool'] === 'default') {
+		return 'goimports';
+	}
+	return goConfig['formatTool'];
+}

src/goLanguageServer.ts

@@ -28,6 +28,7 @@ import {
 	Message,
 	ProvideCodeLensesSignature,
 	ProvideCompletionItemsSignature,
+	ProvideDocumentFormattingEditsSignature,
 	ResponseError,
 	RevealOutputChannelOn
 } from 'vscode-languageclient';
@@ -38,7 +39,7 @@ import { GoCodeActionProvider } from './goCodeAction';
 import { GoDefinitionProvider } from './goDeclaration';
 import { toolExecutionEnvironment } from './goEnv';
 import { GoHoverProvider } from './goExtraInfo';
-import { GoDocumentFormattingEditProvider } from './goFormat';
+import { GoDocumentFormattingEditProvider, usingCustomFormatTool } from './goFormat';
 import { GoImplementationProvider } from './goImplementations';
 import { installTools, latestToolVersion, promptForMissingTool, promptForUpdatingTool } from './goInstallTools';
 import { parseLiveFile } from './goLiveErrors';
@@ -83,6 +84,7 @@ export interface LanguageServerConfig {
 	env: any;
 	features: {
 		diagnostics: boolean;
+		formatter?: GoDocumentFormattingEditProvider;
 	};
 	checkForUpdates: string;
 }
@@ -92,7 +94,7 @@ export interface LanguageServerConfig {
 // new configurations.
 export let languageClient: LanguageClient;
 let languageServerDisposable: vscode.Disposable;
-let latestConfig: LanguageServerConfig;
+export let latestConfig: LanguageServerConfig;
 export let serverOutputChannel: vscode.OutputChannel;
 export let languageServerIsRunning = false;
 
@@ -557,6 +559,17 @@ export async function buildLanguageClient(cfg: BuildLanguageClientOption): Promi
 						}
 					}, []);
 				},
+				provideDocumentFormattingEdits: async (
+					document: vscode.TextDocument,
+					options: vscode.FormattingOptions,
+					token: vscode.CancellationToken,
+					next: ProvideDocumentFormattingEditsSignature
+				) => {
+					if (cfg.features.formatter) {
+						return cfg.features.formatter.provideDocumentFormattingEdits(document, options, token);
+					}
+					return next(document, options, token);
+				},
 				handleDiagnostics: (
 					uri: vscode.Uri,
 					diagnostics: vscode.Diagnostic[],
@@ -889,7 +902,8 @@ export async function watchLanguageServerConfiguration(e: vscode.ConfigurationCh
 		e.affectsConfiguration('go.languageServerFlags') ||
 		e.affectsConfiguration('go.languageServerExperimentalFeatures') ||
 		e.affectsConfiguration('go.alternateTools') ||
-		e.affectsConfiguration('go.toolsEnvVars')
+		e.affectsConfiguration('go.toolsEnvVars') ||
+		e.affectsConfiguration('go.formatTool')
 		// TODO: Should we check http.proxy too? That affects toolExecutionEnvironment too.
 	) {
 		restartLanguageServer();
@@ -901,6 +915,10 @@ export async function watchLanguageServerConfiguration(e: vscode.ConfigurationCh
 }
 
 export function buildLanguageServerConfig(goConfig: vscode.WorkspaceConfiguration): LanguageServerConfig {
+	let formatter: GoDocumentFormattingEditProvider;
+	if (usingCustomFormatTool(goConfig)) {
+		formatter = new GoDocumentFormattingEditProvider();
+	}
 	const cfg: LanguageServerConfig = {
 		serverName: '',
 		path: '',
@@ -911,7 +929,8 @@ export function buildLanguageServerConfig(goConfig: vscode.WorkspaceConfiguratio
 		features: {
 			// TODO: We should have configs that match these names.
 			// Ultimately, we should have a centralized language server config rather than separate fields.
-			diagnostics: goConfig['languageServerExperimentalFeatures']['diagnostics']
+			diagnostics: goConfig['languageServerExperimentalFeatures']['diagnostics'],
+			formatter: formatter
 		},
 		env: toolExecutionEnvironment(),
 		checkForUpdates: getCheckForToolsUpdatesConfig(goConfig)

src/goMain.ts

@@ -102,6 +102,7 @@ import { clearCacheForTools, fileExists, getCurrentGoRoot, setCurrentGoRoot } fr
 import { WelcomePanel } from './welcome';
 import semver = require('semver');
 import vscode = require('vscode');
+import { getFormatTool } from './goFormat';
 
 export let buildDiagnosticCollection: vscode.DiagnosticCollection;
 export let lintDiagnosticCollection: vscode.DiagnosticCollection;
@@ -451,7 +452,7 @@ If you would like additional configuration for diagnostics from gopls, please se
 			}
 
 			if (e.affectsConfiguration('go.formatTool')) {
-				checkToolExists(updatedGoConfig['formatTool']);
+				checkToolExists(getFormatTool(updatedGoConfig));
 			}
 			if (e.affectsConfiguration('go.lintTool')) {
 				checkToolExists(updatedGoConfig['lintTool']);

src/goModules.ts

@@ -9,6 +9,7 @@ import path = require('path');
 import vscode = require('vscode');
 import { getGoConfig } from './config';
 import { toolExecutionEnvironment } from './goEnv';
+import { getFormatTool } from './goFormat';
 import { installTools } from './goInstallTools';
 import { getTool } from './goTools';
 import { getFromGlobalState, updateGlobalState } from './stateUtils';
@@ -74,7 +75,7 @@ export async function getModFolderPath(fileuri: vscode.Uri, isDir?: boolean): Pr
 			);
 		}
 
-		if (goConfig['useLanguageServer'] === false && goConfig['formatTool'] === 'goreturns') {
+		if (goConfig['useLanguageServer'] === false && getFormatTool(goConfig) === 'goreturns') {
 			const promptFormatToolMsg =
 				'The goreturns tool does not support Go modules. Please update the "formatTool" setting to "goimports".';
 			promptToUpdateToolForModules('switchFormatToolToGoimports', promptFormatToolMsg, goConfig);

src/goTools.ts

@@ -11,6 +11,7 @@ import moment = require('moment');
 import path = require('path');
 import semver = require('semver');
 import util = require('util');
+import { getFormatTool, usingCustomFormatTool } from './goFormat';
 import { goLiveErrorsEnabled } from './goLiveErrors';
 import { getBinPath, GoVersion } from './util';
 
@@ -165,8 +166,11 @@ export function getConfiguredTools(goVersion: GoVersion, goConfig: { [key: strin
 			break;
 	}
 
-	// Add the format tool that was chosen by the user.
-	maybeAddTool(goConfig['formatTool']);
+	// Only add format tools if the language server is disabled and the
+	// format tool is known to us.
+	if (goConfig['useLanguageServer'] === false && !usingCustomFormatTool(goConfig)) {
+		maybeAddTool(getFormatTool(goConfig));
+	}
 
 	// Add the linter that was chosen by the user.
 	maybeAddTool(goConfig['lintTool']);

test/gopls/extension.test.ts

@@ -94,7 +94,8 @@ class Env {
 		// Start the language server with the fakeOutputChannel.
 		const goConfig = Object.create(getGoConfig(), {
 			useLanguageServer: { value: true },
-			languageServerFlags: { value: ['-rpc.trace'] } // enable rpc tracing to monitor progress reports
+			languageServerFlags: { value: ['-rpc.trace'] }, // enable rpc tracing to monitor progress reports
+			formatTool: { value: 'nonexistent' } // to test custom formatters
 		});
 		const cfg: BuildLanguageClientOption = buildLanguageServerConfig(goConfig);
 		cfg.outputChannel = this.fakeOutputChannel; // inject our fake output channel.
@@ -245,4 +246,16 @@ suite('Go Extension Tests With Gopls', function () {
 			}
 		}
 	});
+
+	test('Nonexistent formatter', async () => {
+		const { uri } = await env.openDoc(testdataDir, 'gogetdocTestData', 'format.go');
+		const result = (await vscode.commands.executeCommand(
+			'vscode.executeFormatDocumentProvider',
+			uri,
+			{} // empty options
+		)) as vscode.TextEdit[];
+		if (result) {
+			assert.fail(`expected no result, got one: ${result}`);
+		}
+	});
 });

test/testdata/gogetdocTestData/format.go

@@ -0,0 +1,7 @@
+package abc
+
+func hello() {
+
+	var x    int
+	_ = x
+}