feat: implemented the valid-style-parse rule (#1054)

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
 

docs/rules/valid-style-parse.md

@@ -0,0 +1,78 @@
+---
+pageClass: 'rule-details'
+sidebarDepth: 0
+title: 'svelte/valid-style-parse'
+description: 'require valid style element parsing'
+---
+
+# svelte/valid-style-parse
+
+> require valid style element parsing
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> **_This rule has not been released yet._** </badge>
+
+## :book: Rule Details
+
+This rule reports issues with parsing of the `<style>` element by the svelte-eslint-parser.
+
+<!--eslint-skip-->
+
+```svelte
+<script>
+  /* eslint svelte/valid-style-parse: ["error"] */
+</script>
+
+<!-- ✓ GOOD -->
+<style>
+  .class {
+    font-weight: bold;
+  }
+</style>
+```
+
+```svelte
+<script>
+  /* eslint svelte/valid-style-parse: ["error"] */
+</script>
+
+<!-- ✓ GOOD -->
+<style lang="scss">
+  .class {
+    font-weight: bold;
+  }
+</style>
+```
+
+```svelte
+<script>
+  /* eslint svelte/valid-style-parse: ["error"] */
+</script>
+
+<!-- ✗ BAD -->
+<style>
+  .class
+    font-weight: bold;
+</style>
+```
+
+```svelte
+<script>
+  /* eslint svelte/valid-style-parse: ["error"] */
+</script>
+
+<!-- ✗ BAD -->
+<style lang="unknown">
+  .class {
+    font-weight: bold;
+  }
+</style>
+```
+
+## :wrench: Options
+
+Nothing.
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/packages/eslint-plugin-svelte/src/rules/valid-style-parse.ts)
+- [Test source](https://github.com/sveltejs/eslint-plugin-svelte/blob/main/packages/eslint-plugin-svelte/tests/src/rules/valid-style-parse.ts)

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 +1,40 @@
+import { createRule } from '../utils/index.js';
+import { getCwd, 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: {},
+		type: 'problem'
+	},
+	create(context) {
+		const sourceCode = getSourceCode(context);
+		if (!sourceCode.parserServices.isSvelte) {
+			return {};
+		}
+		const cwd = `${getCwd(context)}/`;
+
+		return {
+			SvelteStyleElement(node) {
+				const styleContext = sourceCode.parserServices.getStyleContext!();
+				if (styleContext.status === 'parse-error') {
+					context.report({
+						loc: node.loc,
+						message: `Error parsing style element. Error message: "${styleContext.error.message.replace(cwd, '')}"`
+					});
+				}
+				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[];

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/invalid/invalid-css01-errors.yaml

@@ -0,0 +1,6 @@
+- message: 'Error parsing style element. Error message:
+    "tests/fixtures/rules/valid-style-parse/invalid/invalid-css01-input.svelte:4:11:
+    Unknown word"'
+  line: 7
+  column: 1
+  suggestions: null

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/invalid/invalid-css01-input.svelte

@@ -0,0 +1,18 @@
+<div class="container">
+  <div class="div-class">Hello</div>
+
+  <span class="span-class">World!</span>
+</div>
+
+<style>
+  // This syntax is intentionally invalid CSS - this is to be used to test resiliency against invalid input
+  .container {
+    class .div-class/35
+      # Weird comment
+      color: red;
+
+    .span-class begin
+      font-weight: bold;
+    end
+  }
+</style>

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/invalid/invalid-scss01-errors.yaml

@@ -0,0 +1,6 @@
+- message: 'Error parsing style element. Error message:
+    "tests/fixtures/rules/valid-style-parse/invalid/invalid-scss01-input.svelte:4:11:
+    Unknown word"'
+  line: 7
+  column: 1
+  suggestions: null

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/invalid/invalid-scss01-input.svelte

@@ -0,0 +1,18 @@
+<div class="container">
+  <div class="div-class">Hello</div>
+
+  <span class="span-class">World!</span>
+</div>
+
+<style lang="scss">
+  // This syntax is intentionally invalid CSS - this is to be used to test resiliency against invalid input
+  .container {
+    class .div-class/35
+      # Weird comment
+      color: red;
+
+    .span-class begin
+      font-weight: bold;
+    end
+  }
+</style>

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/invalid/unknown-lang01-errors.yaml

@@ -0,0 +1,4 @@
+- message: Found unsupported style element language "invalid-lang"
+  line: 7
+  column: 1
+  suggestions: null

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/invalid/unknown-lang01-input.svelte

@@ -0,0 +1,18 @@
+<div class="container">
+  <div class="div-class">Hello</div>
+
+  <span class="span-class">World!</span>
+</div>
+
+<style lang="invalid-lang">
+  // This syntax is intentionally invalid CSS - this is to be used to test resiliency against unknown style languages.
+  .container {
+    class .div-class/35
+      # Weird comment
+      color: red;
+
+    .span-class begin
+      font-weight: bold;
+    end
+  }
+</style>

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/valid/no-style01-input.svelte

@@ -0,0 +1,3 @@
+<a href="https://svelte.dev">Hello</a>
+
+<span style="font-weight: bold;">World!</span>

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/valid/valid-css01-input.svelte

@@ -0,0 +1,13 @@
+<div class="div-class">Hello</div>
+
+<span class="span-class">World!</span>
+
+<style>
+	.div-class {
+		color: red;
+	}
+
+	.span-class {
+		font-weight: bold;
+	}
+</style>

packages/eslint-plugin-svelte/tests/fixtures/rules/valid-style-parse/valid/valid-scss01-input.svelte

@@ -0,0 +1,18 @@
+<div class="container">
+	<div class="div-class">Hello</div>
+
+	<span class="span-class">World!</span>
+</div>
+
+<style lang="scss">
+	.container {
+		.div-class {
+			// This is an inline comment
+			color: red;
+		}
+
+		.span-class {
+			font-weight: bold;
+		}
+	}
+</style>

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

@@ -0,0 +1,12 @@
+import { RuleTester } from '../../utils/eslint-compat.js';
+import rule from '../../../src/rules/valid-style-parse.js';
+import { loadTestCases } from '../../utils/utils.js';
+
+const tester = new RuleTester({
+	languageOptions: {
+		ecmaVersion: 2020,
+		sourceType: 'module'
+	}
+});
+
+tester.run('valid-style-parse', rule as any, loadTestCases('valid-style-parse'));