feat: add ability to ignore warnings through compiler option

Some people want to disable certain warnings for their whole application without having to add svelte-ignore comments everywhere. This new option makes that possible.
closes #9188
part of https://github.com/sveltejs/language-tools/issues/650

.changeset/little-seals-reflect.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+feat: add ability to ignore warnings through compiler option

packages/svelte/src/compiler/state.js

@@ -44,7 +44,7 @@ export function pop_ignore() {
 
 /**
  * @param {string} source
- * @param {{ filename?: string, rootDir?: string }} options
+ * @param {{ filename?: string, rootDir?: string, warnings?: { ignore?: string[] } }} options
  */
 export function reset(source, options) {
 	const root_dir = options.rootDir?.replace(/\\/g, '/');
@@ -63,4 +63,8 @@ export function reset(source, options) {
 	warnings = [];
 	ignore_stack = [];
 	ignore_map.clear();
+
+	if (options.warnings?.ignore) {
+		push_ignore(options.warnings.ignore);
+	}
 }

packages/svelte/src/compiler/types/index.d.ts

@@ -211,12 +211,20 @@ export interface ModuleCompileOptions {
 	 * Used for debugging hints and sourcemaps. Your bundler plugin will set it automatically.
 	 */
 	filename?: string;
-
 	/**
 	 * Used for ensuring filenames don't leak filesystem information. Your bundler plugin will set it automatically.
 	 * @default process.cwd() on node-like environments, undefined elsewhere
 	 */
 	rootDir?: string;
+	/**
+	 * Options related to Svelte's warnings
+	 */
+	warnings?: {
+		/**
+		 * A list of warning codes to suppress. If a warning is emitted with a code in this list, it will be ignored.
+		 */
+		ignore?: string[];
+	};
 }
 
 // The following two somewhat scary looking types ensure that certain types are required but can be undefined still

packages/svelte/src/compiler/validate-options.js

@@ -100,6 +100,10 @@ export const validate_component_options =
 
 			hmr: boolean(false),
 
+			warnings: object({
+				ignore: string_array([])
+			}),
+
 			sourcemap: validator(undefined, (input) => {
 				// Source maps can take on a variety of values, including string, JSON, map objects from magic-string and source-map,
 				// so there's no good way to check type validity here
@@ -255,6 +259,20 @@ function string(fallback, allow_empty = true) {
 	});
 }
 
+/**
+ * @param {string[]} fallback
+ * @returns {Validator}
+ */
+function string_array(fallback) {
+	return validator(fallback, (input, keypath) => {
+		if (input && !Array.isArray(input)) {
+			throw_error(`${keypath} should be a string array, if specified`);
+		}
+
+		return input;
+	});
+}
+
 /**
  * @param {boolean | undefined} fallback
  * @returns {Validator}

packages/svelte/tests/validator/samples/ignore-warning-compiler-option/_config.js

@@ -0,0 +1,9 @@
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		warnings: {
+			ignore: ['a11y_missing_attribute', 'a11y_misplaced_scope']
+		}
+	}
+});

packages/svelte/tests/validator/samples/ignore-warning-compiler-option/input.svelte

@@ -0,0 +1,8 @@
+<div>
+	<img src="this-is-fine.jpg" />
+	<marquee>but this is still discouraged</marquee>
+</div>
+
+<div scope></div>
+
+<img src="potato.jpg" />

packages/svelte/tests/validator/samples/ignore-warning-compiler-option/warnings.json

@@ -0,0 +1,14 @@
+[
+	{
+		"code": "a11y_distracting_elements",
+		"end": {
+			"column": 49,
+			"line": 3
+		},
+		"message": "Avoid `<marquee>` elements",
+		"start": {
+			"column": 1,
+			"line": 3
+		}
+	}
+]

packages/svelte/types/index.d.ts

@@ -870,12 +870,20 @@ declare module 'svelte/compiler' {
 		 * Used for debugging hints and sourcemaps. Your bundler plugin will set it automatically.
 		 */
 		filename?: string;
-
 		/**
 		 * Used for ensuring filenames don't leak filesystem information. Your bundler plugin will set it automatically.
 		 * @default process.cwd() on node-like environments, undefined elsewhere
 		 */
 		rootDir?: string;
+		/**
+		 * Options related to Svelte's warnings
+		 */
+		warnings?: {
+			/**
+			 * A list of warning codes to suppress. If a warning is emitted with a code in this list, it will be ignored.
+			 */
+			ignore?: string[];
+		};
 	}
 
 	type DeclarationKind =
@@ -2693,12 +2701,20 @@ declare module 'svelte/types/compiler/interfaces' {
 		 * Used for debugging hints and sourcemaps. Your bundler plugin will set it automatically.
 		 */
 		filename?: string;
-
 		/**
 		 * Used for ensuring filenames don't leak filesystem information. Your bundler plugin will set it automatically.
 		 * @default process.cwd() on node-like environments, undefined elsewhere
 		 */
 		rootDir?: string;
+		/**
+		 * Options related to Svelte's warnings
+		 */
+		warnings?: {
+			/**
+			 * A list of warning codes to suppress. If a warning is emitted with a code in this list, it will be ignored.
+			 */
+			ignore?: string[];
+		};
 	}
 	/**
 	 * - `html`    — the default, for e.g. `<div>` or `<span>`