feat(valid-style-parse): implemented the rule

Author: marekdedic

.changeset/stupid-penguins-smoke.md

@@ -0,0 +1,5 @@
+---
+'eslint-plugin-svelte': minor
+---
+
+feat: added the valid-style-parse rule

README.md

@@ -335,6 +335,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/require-store-callbacks-use-set-param](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-store-callbacks-use-set-param/) | store callbacks must use `set` param |  |
 | [svelte/require-store-reactive-access](https://sveltejs.github.io/eslint-plugin-svelte/rules/require-store-reactive-access/) | disallow to use of the store itself as an operand. Need to use $ prefix or get function. | :star::wrench: |
 | [svelte/valid-compile](https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-compile/) | disallow warnings when compiling. |  |
+| [svelte/valid-style-parse](https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-style-parse/) | require valid style element parsing |  |
 
 ## Security Vulnerability
 

docs/rules.md

@@ -32,6 +32,7 @@ These rules relate to possible syntax or logic errors in Svelte code:
 | [svelte/require-store-callbacks-use-set-param](./rules/require-store-callbacks-use-set-param.md) | store callbacks must use `set` param                                                                                                   |                |
 | [svelte/require-store-reactive-access](./rules/require-store-reactive-access.md)                 | disallow to use of the store itself as an operand. Need to use $ prefix or get function.                                               | :star::wrench: |
 | [svelte/valid-compile](./rules/valid-compile.md)                                                 | disallow warnings when compiling.                                                                                                      |                |
+| [svelte/valid-style-parse](./rules/valid-style-parse.md)                                         | require valid style element parsing                                                                                                    |                |
 
 ## Security Vulnerability
 

packages/eslint-plugin-svelte/src/rule-types.ts

@@ -366,6 +366,11 @@ export interface RuleOptions {
    * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-prop-names-in-kit-pages/
    */
   'svelte/valid-prop-names-in-kit-pages'?: Linter.RuleEntry<[]>
+  /**
+   * require valid style element parsing
+   * @see https://sveltejs.github.io/eslint-plugin-svelte/rules/valid-style-parse/
+   */
+  'svelte/valid-style-parse'?: Linter.RuleEntry<[]>
 }
 
 /* ======= Declarations ======= */

packages/eslint-plugin-svelte/src/rules/valid-style-parse.ts

@@ -0,0 +1,41 @@
+import { createRule } from '../utils/index.js';
+import { getSourceCode } from '../utils/compat.js';
+
+export default createRule('valid-style-parse', {
+	meta: {
+		docs: {
+			description: 'require valid style element parsing',
+			category: 'Possible Errors',
+			recommended: false
+		},
+		schema: [],
+		messages: {
+			parseError: 'Error parsing style element'
+		},
+		type: 'problem'
+	},
+	create(context) {
+		const sourceCode = getSourceCode(context);
+		if (!sourceCode.parserServices.isSvelte) {
+			return {};
+		}
+
+		return {
+			SvelteStyleElement(node) {
+				const styleContext = sourceCode.parserServices.getStyleContext!();
+				if (styleContext.status === 'parse-error') {
+					context.report({
+						loc: node.loc,
+						messageId: 'parseError'
+					});
+				}
+				if (styleContext.status === 'unknown-lang') {
+					context.report({
+						loc: node.loc,
+						message: `Found unsupported style element language "${styleContext.sourceLang}"`
+					});
+				}
+			}
+		};
+	}
+});

packages/eslint-plugin-svelte/src/utils/rules.ts

@@ -72,6 +72,7 @@ import system from '../rules/system.js';
 import validCompile from '../rules/valid-compile.js';
 import validEachKey from '../rules/valid-each-key.js';
 import validPropNamesInKitPages from '../rules/valid-prop-names-in-kit-pages.js';
+import validStyleParse from '../rules/valid-style-parse.js';
 
 export const rules = [
 	typescriptEslintNoUnnecessaryCondition,
@@ -143,5 +144,6 @@ export const rules = [
 	system,
 	validCompile,
 	validEachKey,
-	validPropNamesInKitPages
+	validPropNamesInKitPages,
+	validStyleParse
 ] as RuleModule[];