fix(migration): add Svelte rune globals to Oxlint config

crates/vite_cli_snapshots/tests/cli_snapshots/fixtures/migration_eslint_svelte_runes/eslint.config.mjs

@@ -0,0 +1,14 @@
+export default [
+  {
+    rules: {
+      'no-undef': 'error',
+    },
+  },
+  {
+    files: ['*.svelte', '**/*.svelte'],
+    rules: {
+      'no-inner-declarations': 'off',
+      'no-self-assign': 'off',
+    },
+  },
+];

crates/vite_cli_snapshots/tests/cli_snapshots/fixtures/migration_eslint_svelte_runes/package.json

@@ -0,0 +1,10 @@
+{
+  "name": "migration-eslint-svelte-runes",
+  "scripts": {
+    "lint": "eslint ."
+  },
+  "devDependencies": {
+    "eslint": "^9.0.0",
+    "vite": "^7.0.0"
+  }
+}

crates/vite_cli_snapshots/tests/cli_snapshots/fixtures/migration_eslint_svelte_runes/snapshots.toml

@@ -0,0 +1,8 @@
+[[case]]
+name = "migration_eslint_svelte_runes"
+vp = "global"
+steps = [
+  { argv = ["vp", "migrate", "--no-interactive"], comment = "migration should add Svelte rune globals to the lint override", continue-on-failure = true },
+  { argv = ["vpt", "print-file", "vite.config.ts"], comment = "Svelte override includes every built-in rune as a readonly global", continue-on-failure = true },
+  { argv = ["vp", "lint", "src/App.svelte"], comment = "valid Svelte rune usage should pass no-undef", continue-on-failure = true },
+]

crates/vite_cli_snapshots/tests/cli_snapshots/fixtures/migration_eslint_svelte_runes/snapshots/migration_eslint_svelte_runes.md

@@ -0,0 +1,89 @@
+# migration_eslint_svelte_runes
+
+## `vp migrate --no-interactive`
+
+migration should add Svelte rune globals to the lint override
+
+```
+VITE+ - The Unified Toolchain for the Web
+
+◇ Migrated . to Vite+ <version>
+• Node <version>  pnpm <version>
+• 4 config updates applied
+• ESLint rules migrated to Oxlint
+```
+
+## `vpt print-file vite.config.ts`
+
+Svelte override includes every built-in rune as a readonly global
+
+```
+import { defineConfig } from 'vite-plus';
+
+export default defineConfig({
+  staged: {
+    "*": "vp check --fix"
+  },
+  fmt: {},
+  lint: {
+    "plugins": [
+      "oxc",
+      "typescript",
+      "unicorn",
+      "react"
+    ],
+    "categories": {
+      "correctness": "warn"
+    },
+    "env": {
+      "builtin": true
+    },
+    "rules": {
+      "no-undef": "error",
+      "vite-plus/prefer-vite-plus-imports": "error"
+    },
+    "overrides": [
+      {
+        "files": [
+          "*.svelte",
+          "**/*.svelte"
+        ],
+        "rules": {
+          "no-inner-declarations": "off",
+          "no-self-assign": "off"
+        },
+        "globals": {
+          "$state": "readonly",
+          "$derived": "readonly",
+          "$effect": "readonly",
+          "$props": "readonly",
+          "$bindable": "readonly",
+          "$inspect": "readonly",
+          "$host": "readonly"
+        }
+      }
+    ],
+    "options": {
+      "typeAware": true,
+      "typeCheck": true
+    },
+    "jsPlugins": [
+      {
+        "name": "vite-plus",
+        "specifier": "vite-plus/oxlint-plugin"
+      }
+    ]
+  },
+});
+```
+
+## `vp lint src/App.svelte`
+
+valid Svelte rune usage should pass no-undef
+
+```
+VITE+ - The Unified Toolchain for the Web
+
+Found 0 warnings and 0 errors.
+Finished in <duration> on 1 file with <n> rules using <n> threads.
+```

crates/vite_cli_snapshots/tests/cli_snapshots/fixtures/migration_eslint_svelte_runes/src/App.svelte

@@ -0,0 +1,5 @@
+<script>
+  let { name = 'world' } = $props();
+</script>
+
+<h1>Hello {name}</h1>

packages/cli/src/migration/__tests__/migrator.spec.ts

@@ -42,6 +42,8 @@ const {
   injectCreateDefaultTemplate,
   injectFmtDefaults,
   injectLintTypeCheckDefaults,
+  ensureSvelteRuneGlobals,
+  mergeViteConfigFiles,
   rewriteEslintPackageJson,
   collectInstalledPackageNames,
   sanitizeMigratedOxlintConfig,
@@ -1172,6 +1174,106 @@ describe('collectInstalledPackageNames', () => {
   });
 });
 
+describe('ensureSvelteRuneGlobals', () => {
+  it('adds all built-in runes to Svelte overrides', () => {
+    const config: import('oxlint').OxlintConfig = {
+      overrides: [{ files: ['*.svelte', '**/*.svelte.ts'] }],
+    };
+
+    ensureSvelteRuneGlobals(config);
+
+    expect(config.overrides?.[0]?.globals).toEqual({
+      $state: 'readonly',
+      $derived: 'readonly',
+      $effect: 'readonly',
+      $props: 'readonly',
+      $bindable: 'readonly',
+      $inspect: 'readonly',
+      $host: 'readonly',
+    });
+  });
+
+  it('preserves existing globals and explicit rune values', () => {
+    const config: import('oxlint').OxlintConfig = {
+      overrides: [
+        {
+          files: ['**/*.svelte'],
+          globals: { customGlobal: 'writable', $state: 'writable' },
+        },
+      ],
+    };
+
+    ensureSvelteRuneGlobals(config);
+
+    expect(config.overrides?.[0]?.globals).toMatchObject({
+      customGlobal: 'writable',
+      $state: 'writable',
+      $props: 'readonly',
+    });
+  });
+
+  it('detects Svelte in brace-expanded override patterns', () => {
+    const config: import('oxlint').OxlintConfig = {
+      overrides: [{ files: ['**/*.{js,ts,svelte}'] }],
+    };
+
+    ensureSvelteRuneGlobals(config);
+
+    expect(config.overrides?.[0]?.globals).toMatchObject({
+      $props: 'readonly',
+    });
+  });
+
+  it('does not modify unrelated or negated-only overrides', () => {
+    const config: import('oxlint').OxlintConfig = {
+      overrides: [{ files: ['**/*.ts'] }, { files: ['!**/*.svelte'] }],
+    };
+
+    ensureSvelteRuneGlobals(config);
+
+    expect(config.overrides).toEqual([{ files: ['**/*.ts'] }, { files: ['!**/*.svelte'] }]);
+  });
+});
+
+describe('mergeViteConfigFiles — Svelte rune globals', () => {
+  let tmpDir: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'vp-test-svelte-runes-'));
+    fs.writeFileSync(path.join(tmpDir, 'package.json'), JSON.stringify({ name: 'test' }));
+    fs.writeFileSync(
+      path.join(tmpDir, 'vite.config.ts'),
+      "import { defineConfig } from 'vite-plus';\n\nexport default defineConfig({});\n",
+    );
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+  });
+
+  it('merges built-in rune globals into the final lint config', () => {
+    fs.writeFileSync(
+      path.join(tmpDir, '.oxlintrc.json'),
+      JSON.stringify({
+        overrides: [
+          {
+            files: ['**/*.{js,ts,svelte}'],
+            globals: { customGlobal: 'writable' },
+          },
+        ],
+      }),
+    );
+
+    mergeViteConfigFiles(tmpDir, true);
+
+    const viteConfig = fs.readFileSync(path.join(tmpDir, 'vite.config.ts'), 'utf8');
+    expect(viteConfig).toMatch(/["']\$props["']\s*:\s*["']readonly["']/);
+    expect(viteConfig).toMatch(/["']\$host["']\s*:\s*["']readonly["']/);
+    expect(viteConfig).toMatch(/["']customGlobal["']\s*:\s*["']writable["']/);
+    expect(fs.existsSync(path.join(tmpDir, '.oxlintrc.json'))).toBe(false);
+  });
+});
+
 function writePkgAt(dir: string, pkg: object): void {
   fs.mkdirSync(dir, { recursive: true });
   fs.writeFileSync(path.join(dir, 'package.json'), JSON.stringify(pkg));

packages/cli/src/migration/migrator/vite-config.ts

@@ -2,6 +2,7 @@ import fs from 'node:fs';
 import path from 'node:path';
 
 import * as prompts from '@voidzero-dev/vite-plus-prompts';
+import { braceExpand } from 'minimatch';
 import { type OxlintConfig } from 'oxlint';
 
 import {
@@ -35,6 +36,34 @@ import {
   warnMigration,
 } from './shared.ts';
 
+const SVELTE_RUNE_GLOBALS = {
+  $state: 'readonly',
+  $derived: 'readonly',
+  $effect: 'readonly',
+  $props: 'readonly',
+  $bindable: 'readonly',
+  $inspect: 'readonly',
+  $host: 'readonly',
+} satisfies Record<string, 'readonly'>;
+
+// Add Svelte's built-in rune globals to migrated Svelte overrides.
+// https://github.com/oxc-project/oxc/issues/20191
+export function ensureSvelteRuneGlobals(config: OxlintConfig): void {
+  for (const override of config.overrides ?? []) {
+    const targetsSvelte = override.files.some(
+      (file: string) =>
+        !file.startsWith('!') && braceExpand(file).some((pattern) => pattern.includes('.svelte')),
+    );
+    if (!targetsSvelte) {
+      continue;
+    }
+    override.globals = {
+      ...SVELTE_RUNE_GLOBALS,
+      ...override.globals,
+    };
+  }
+}
+
 // Remove the "lint-staged" key from package.json after config has been
 // successfully merged into vite.config.ts.
 export function removeLintStagedFromPackageJson(packageJsonPath: string): void {
@@ -231,6 +260,7 @@ export function mergeViteConfigFiles(
       collectInstalledPackageNames(workspaceRoot ?? projectPath, packages),
       report,
     );
+    ensureSvelteRuneGlobals(oxlintJson);
     const normalizedOxlintConfig = ensureVitePlusImportRuleDefaults(oxlintJson);
     // writeJsonFile preserves the user file's existing indent/newline (and adds a
     // trailing newline) instead of forcing 2-space + no EOL.