(feat) possibility to ignore compiler warnings/treat them as errors

packages/language-server/src/index.ts

@@ -1,3 +1,3 @@
 export * from './server';
 export { offsetAt } from './lib/documents';
-export { SvelteCheck } from './svelte-check';
+export { SvelteCheck, SvelteCheckOptions } from './svelte-check';

packages/language-server/src/ls-config.ts

@@ -32,6 +32,7 @@ const defaultLSConfig: LSConfig = {
     },
     svelte: {
         enable: true,
+        compilerWarnings: {},
         diagnostics: { enable: true },
         format: { enable: true },
         completions: { enable: true },
@@ -114,8 +115,11 @@ export interface LSHTMLConfig {
     };
 }
 
+export type CompilerWarningsSettings = Record<string, 'ignore' | 'error'>;
+
 export interface LSSvelteConfig {
     enable: boolean;
+    compilerWarnings: CompilerWarningsSettings;
     diagnostics: {
         enable: boolean;
     };
@@ -133,25 +137,51 @@ export interface LSSvelteConfig {
     };
 }
 
+type DeepPartial<T> = T extends CompilerWarningsSettings
+    ? T
+    : {
+          [P in keyof T]?: DeepPartial<T[P]>;
+      };
+
 export class LSConfigManager {
     private config: LSConfig = defaultLSConfig;
 
     /**
      * Updates config.
      */
-    update(config: LSConfig): void {
+    update(config: DeepPartial<LSConfig>): void {
         // Ideally we shouldn't need the merge here because all updates should be valid and complete configs.
         // But since those configs come from the client they might be out of synch with the valid config:
         // We might at some point in the future forget to synch config settings in all packages after updating the config.
         this.config = merge({}, defaultLSConfig, this.config, config);
+        // Merge will keep arrays/objects if the new one is empty/has less entries,
+        // therefore we need some extra checks if there are new settings
+        if (config.svelte?.compilerWarnings) {
+            this.config.svelte.compilerWarnings = config.svelte.compilerWarnings;
+        }
     }
 
     /**
      * Whether or not specified config is enabled
      * @param key a string which is a path. Example: 'svelte.diagnostics.enable'.
      */
     enabled(key: string): boolean {
-        return !!get(this.config, key);
+        return !!this.get(key);
+    }
+
+    /**
+     * Get specific config
+     * @param key a string which is a path. Example: 'svelte.diagnostics.enable'.
+     */
+    get<T>(key: string): T {
+        return get(this.config, key);
+    }
+
+    /**
+     * Get the whole config
+     */
+    getConfig(): Readonly<LSConfig> {
+        return this.config;
     }
 }
 

packages/language-server/src/plugins/svelte/SveltePlugin.ts

@@ -1,4 +1,3 @@
-import { cosmiconfig } from 'cosmiconfig';
 import {
     CodeAction,
     CodeActionContext,
@@ -34,10 +33,6 @@ export class SveltePlugin
         HoverProvider,
         CodeActionsProvider {
     private docManager = new Map<Document, SvelteDocument>();
-    private cosmiConfigExplorer = cosmiconfig('svelte', {
-        packageProp: 'svelte-ls',
-        cache: true,
-    });
 
     constructor(private configManager: LSConfigManager, private prettierConfig: any) {}
 
@@ -46,7 +41,11 @@ export class SveltePlugin
             return [];
         }
 
-        return getDiagnostics(document, await this.getSvelteDoc(document));
+        return getDiagnostics(
+            document,
+            await this.getSvelteDoc(document),
+            this.configManager.getConfig().svelte.compilerWarnings,
+        );
     }
 
     async getCompiledResult(document: Document): Promise<SvelteCompileResult | null> {

packages/language-server/src/plugins/svelte/features/getDiagnostics.ts

@@ -3,6 +3,7 @@ import { Diagnostic, DiagnosticSeverity, Position, Range } from 'vscode-language
 import { Document, isInTag, mapDiagnosticToOriginal } from '../../../lib/documents';
 import { Logger } from '../../../logger';
 import { SvelteDocument, TranspileErrorSource } from '../SvelteDocument';
+import { CompilerWarningsSettings } from '../../../ls-config';
 
 /**
  * Returns diagnostics from the svelte compiler.
@@ -11,13 +12,14 @@ import { SvelteDocument, TranspileErrorSource } from '../SvelteDocument';
 export async function getDiagnostics(
     document: Document,
     svelteDoc: SvelteDocument,
+    settings: CompilerWarningsSettings,
 ): Promise<Diagnostic[]> {
     if (svelteDoc.config.loadConfigError) {
         return getConfigLoadErrorDiagnostics(svelteDoc.config.loadConfigError);
     }
 
     try {
-        return await tryGetDiagnostics(document, svelteDoc);
+        return await tryGetDiagnostics(document, svelteDoc, settings);
     } catch (error) {
         return getPreprocessErrorDiagnostics(document, error);
     }
@@ -29,19 +31,24 @@ export async function getDiagnostics(
 async function tryGetDiagnostics(
     document: Document,
     svelteDoc: SvelteDocument,
+    settings: CompilerWarningsSettings,
 ): Promise<Diagnostic[]> {
     const transpiled = await svelteDoc.getTranspiled();
 
     try {
         const res = await svelteDoc.getCompiled();
         return (((res.stats as any).warnings || res.warnings || []) as Warning[])
+            .filter((warning) => settings[warning.code] !== 'ignore')
             .map((warning) => {
                 const start = warning.start || { line: 1, column: 0 };
                 const end = warning.end || start;
                 return {
                     range: Range.create(start.line - 1, start.column, end.line - 1, end.column),
                     message: warning.message,
-                    severity: DiagnosticSeverity.Warning,
+                    severity:
+                        settings[warning.code] === 'error'
+                            ? DiagnosticSeverity.Error
+                            : DiagnosticSeverity.Warning,
                     source: 'svelte',
                     code: warning.code,
                 };

packages/language-server/src/svelte-check.ts

@@ -5,6 +5,10 @@ import { Diagnostic } from 'vscode-languageserver';
 import { Logger } from './logger';
 import { urlToPath } from './utils';
 
+export interface SvelteCheckOptions {
+    compilerWarnings?: Record<string, 'ignore' | 'error'>;
+}
+
 /**
  * Small wrapper around PluginHost's Diagnostic Capabilities
  * for svelte-check, without the overhead of the lsp.
@@ -16,12 +20,17 @@ export class SvelteCheck {
     private configManager = new LSConfigManager();
     private pluginHost = new PluginHost(this.docManager, this.configManager);
 
-    constructor(workspacePath: string) {
+    constructor(workspacePath: string, options: SvelteCheckOptions = {}) {
         Logger.setLogErrorsOnly(true);
-        this.initialize(workspacePath);
+        this.initialize(workspacePath, options);
     }
 
-    private initialize(workspacePath: string) {
+    private initialize(workspacePath: string, options: SvelteCheckOptions) {
+        this.configManager.update({
+            svelte: {
+                compilerWarnings: options.compilerWarnings,
+            },
+        });
         this.pluginHost.register(new SveltePlugin(this.configManager, {}));
         this.pluginHost.register(new HTMLPlugin(this.docManager, this.configManager));
         this.pluginHost.register(new CSSPlugin(this.docManager, this.configManager));

packages/language-server/test/plugins/svelte/features/getDiagnostics.test.ts

@@ -7,16 +7,18 @@ import {
     TranspileErrorSource,
 } from '../../../../src/plugins/svelte/SvelteDocument';
 import { SvelteConfig } from '../../../../src/lib/documents/configLoader';
+import { CompilerWarningsSettings } from '../../../../src/ls-config';
 
 describe('SveltePlugin#getDiagnostics', () => {
     async function expectDiagnosticsFor(
         getTranspiled: any,
         getCompiled: any,
         config: Partial<SvelteConfig>,
+        settings: CompilerWarningsSettings = {},
     ) {
         const document = new Document('', '<script></script>\n<style></style>');
         const svelteDoc: SvelteDocument = <any>{ getTranspiled, getCompiled, config };
-        const result = await getDiagnostics(document, svelteDoc);
+        const result = await getDiagnostics(document, svelteDoc, settings);
         return {
             toEqual: (expected: Diagnostic[]) => assert.deepStrictEqual(result, expected),
         };
@@ -259,4 +261,77 @@ describe('SveltePlugin#getDiagnostics', () => {
             },
         ]);
     });
+
+    it('filter out warnings', async () => {
+        (
+            await expectDiagnosticsFor(
+                () => ({
+                    getOriginalPosition: (pos: Position) => {
+                        pos.line - 1;
+                        return pos;
+                    },
+                }),
+                () =>
+                    Promise.resolve({
+                        stats: {
+                            warnings: [
+                                {
+                                    start: { line: 1, column: 0 },
+                                    end: { line: 1, column: 0 },
+                                    message: 'warning',
+                                    code: '123',
+                                },
+                            ],
+                        },
+                    }),
+                {},
+                { '123': 'ignore' },
+            )
+        ).toEqual([]);
+    });
+
+    it('treat warnings as error', async () => {
+        (
+            await expectDiagnosticsFor(
+                () => ({
+                    getOriginalPosition: (pos: Position) => {
+                        pos.line - 1;
+                        return pos;
+                    },
+                }),
+                () =>
+                    Promise.resolve({
+                        stats: {
+                            warnings: [
+                                {
+                                    start: { line: 1, column: 0 },
+                                    end: { line: 1, column: 0 },
+                                    message: 'warning',
+                                    code: '123',
+                                },
+                            ],
+                        },
+                    }),
+                {},
+                { '123': 'error' },
+            )
+        ).toEqual([
+            {
+                code: '123',
+                message: 'warning',
+                range: {
+                    start: {
+                        character: 0,
+                        line: 0,
+                    },
+                    end: {
+                        character: 0,
+                        line: 0,
+                    },
+                },
+                severity: DiagnosticSeverity.Error,
+                source: 'svelte',
+            },
+        ]);
+    });
 });

packages/svelte-check/README.md

@@ -60,6 +60,8 @@ Usage:
 
 `--fail-on-warnings` Will also exit with error code when there are warnings
 
+`--compiler-warnings <code1:error|ignore,code2:error|ignore>` A list of Svelte compiler warning codes. Each entry defines whether that warning should be ignored or treated as an error. Warnings are comma-separated, between warning code and error level is a colon; all inside quotes. Example: --compiler-warnings "css-unused-selector:ignore,unused-export-let:error"
+
 ### More docs, preprocessor setup and troubleshooting
 
 [See here](/docs/README.md).

packages/svelte-check/src/index.ts

@@ -6,7 +6,7 @@ import * as fs from 'fs';
 import * as glob from 'glob';
 import * as argv from 'minimist';
 import * as path from 'path';
-import { SvelteCheck } from 'svelte-language-server';
+import { SvelteCheck, SvelteCheckOptions } from 'svelte-language-server';
 import { Diagnostic, DiagnosticSeverity } from 'vscode-languageserver-protocol';
 import { URI } from 'vscode-uri';
 import { HumanFriendlyWriter, MachineFriendlyWriter, Writer } from './writers';
@@ -122,6 +122,38 @@ class DiagnosticsWatcher {
     }
 }
 
+function instantiateWriter(myArgs: argv.ParsedArgs): Writer {
+    const outputFormat: OutputFormat = outputFormats.includes(myArgs['output'])
+        ? myArgs['output']
+        : 'human-verbose';
+
+    if (outputFormat === 'human-verbose' || outputFormat === 'human') {
+        return new HumanFriendlyWriter(process.stdout, outputFormat === 'human-verbose');
+    } else {
+        return new MachineFriendlyWriter(process.stdout);
+    }
+}
+
+function getOptions(myArgs: argv.ParsedArgs): SvelteCheckOptions {
+    return {
+        compilerWarnings: stringToObj(myArgs['compiler-warnings']),
+    };
+
+    function stringToObj(str = '') {
+        return str
+            .split(',')
+            .map((s) => s.trim())
+            .filter((s) => !!s)
+            .reduce((settings, setting) => {
+                const [name, val] = setting.split(':');
+                if (val === 'error' || val === 'ignore') {
+                    settings[name] = val;
+                }
+                return settings;
+            }, <Record<string, 'error' | 'ignore'>>{});
+    }
+}
+
 (async () => {
     const myArgs = argv(process.argv.slice(1));
     let workspaceUri;
@@ -136,18 +168,9 @@ class DiagnosticsWatcher {
         workspaceUri = URI.file(process.cwd());
     }
 
-    const outputFormat: OutputFormat = outputFormats.includes(myArgs['output'])
-        ? myArgs['output']
-        : 'human-verbose';
-    let writer: Writer;
-
-    if (outputFormat === 'human-verbose' || outputFormat === 'human') {
-        writer = new HumanFriendlyWriter(process.stdout, outputFormat === 'human-verbose');
-    } else {
-        writer = new MachineFriendlyWriter(process.stdout);
-    }
+    const writer = instantiateWriter(myArgs);
 
-    const svelteCheck = new SvelteCheck(workspaceUri.fsPath);
+    const svelteCheck = new SvelteCheck(workspaceUri.fsPath, getOptions(myArgs));
     const filePathsToIgnore = myArgs['ignore']?.split(',') || [];
 
     if (myArgs['watch']) {

packages/svelte-vscode/README.md

@@ -148,6 +148,10 @@ Enable the Svelte plugin. _Default_: `true`
 
 Enable diagnostic messages for Svelte. _Default_: `true`
 
+##### `svelte.plugin.svelte.compilerWarnings`
+
+Svelte compiler warning codes to ignore or to treat as errors. Example: { 'css-unused-selector': 'ignore', 'unused-export-let': 'error'}
+
 ##### `svelte.plugin.svelte.format.enable`
 
 Enable formatting for Svelte (includes css & js). _Default_: `true`

packages/svelte-vscode/package.json

@@ -188,6 +188,19 @@
                     "title": "Svelte: Diagnostics",
                     "description": "Enable diagnostic messages for Svelte"
                 },
+                "svelte.plugin.svelte.compilerWarnings": {
+                    "type": "object",
+                    "additionalProperties": {
+                        "type": "string",
+                        "enum": [
+                            "ignore",
+                            "error"
+                        ]
+                    },
+                    "default": {},
+                    "title": "Svelte: Compiler Warnings Settings",
+                    "description": "Svelte compiler warning codes to ignore or to treat as errors. Example: { 'css-unused-selector': 'ignore', 'unused-export-let': 'error'}"
+                },
                 "svelte.plugin.svelte.format.enable": {
                     "type": "boolean",
                     "default": true,