NativeScript · NathanWalker · Sep 29, 2026 · Sep 28, 2026 · Sep 29, 2026
diff --git a/packages/vite/hmr/server/device-transform-helpers.ts b/packages/vite/hmr/server/device-transform-helpers.ts
@@ -6,7 +6,7 @@ import * as path from 'path';
 import { existsSync } from 'fs';
 import * as PAT from './constants.js';
 import { getProjectRootPath } from '../../helpers/project.js';
-import { isLikelyNativeScriptRuntimePluginSpecifier, isNativeScriptCoreModule, isNativeScriptPluginModule, normalizeNativeScriptCoreSpecifier, normalizeNodeModulesSpecifier, resolveNodeModulesPackageBoundary, resolveVendorFromCandidate, viteDepsPathToBareSpecifier } from './websocket-module-specifiers.js';
+import { decodeFlattenedId, isLikelyNativeScriptRuntimePluginSpecifier, isNativeScriptCoreModule, isNativeScriptPluginModule, normalizeNativeScriptCoreSpecifier, normalizeNodeModulesSpecifier, resolveNodeModulesPackageBoundary, resolveVendorFromCandidate, viteDepsPathToBareSpecifier } from './websocket-module-specifiers.js';
 import { collectTopLevelImportRecords } from './websocket-served-module-helpers.js';
 
 // Bare specifiers and special skip patterns (virtual, data:, etc.)
@@ -17,6 +17,15 @@ const SKIP_PATTERNS = /^(?:data:|blob:|node:|virtual:|vite:|\0|\/@@?id|\/__vite|
 // the console on every served module.
 const warnedVendorMisses = new Set<string>();
 
+function packageIsInstalled(packageName: string): boolean {
+	if (!packageName) return false;
+	try {
+		return existsSync(path.join(getProjectRootPath(), 'node_modules', ...packageName.split('/'), 'package.json'));
+	} catch {
+		return false;
+	}
+}
+
 /**
  * Vendor-manifest miss fallback — e.g. `emoji-regex`, a transitive dep of
  * @nativescript/core that is never part of the vendor bundle. Dropping the
@@ -32,26 +41,6 @@ const warnedVendorMisses = new Set<string>();
  * being committed; if nothing resolves, the first candidate is used anyway —
  * a loud 404 on device beats a silent undefined binding.
  */
-function decodeFlattenedDepId(flat: string): string {
-	// Reverse Vite's flattenId, which encodes '.' as '__' and '/' (and ':') as
-	// '_'. Split on the '__' (dot) boundaries first so a single '_' inside each
-	// segment becomes a '/', then rejoin the segments with '.'. This avoids any
-	// placeholder sentinel (a literal NUL would corrupt the served module).
-	return flat
-		.split('__')
-		.map((segment) => segment.replace(/_/g, '/'))
-		.join('.');
-}
-
-function packageIsInstalled(packageName: string): boolean {
-	if (!packageName) return false;
-	try {
-		return existsSync(path.join(getProjectRootPath(), 'node_modules', ...packageName.split('/'), 'package.json'));
-	} catch {
-		return false;
-	}
-}
-
 function bareSpecifierFromFlatDepPath(depPath: string): string {
 	const flat = depPath.split('?')[0].replace(/\.m?js$/, '');
 	// flattenId is lossy (names may contain '_'), so build candidates from the
@@ -64,7 +53,7 @@ function bareSpecifierFromFlatDepPath(depPath: string): string {
 	const pushCandidate = (c: string) => {
 		if (c && !candidates.includes(c)) candidates.push(c);
 	};
-	pushCandidate(decodeFlattenedDepId(flat));
+	pushCandidate(decodeFlattenedId(flat));
 	if (flat.startsWith('@')) {
 		// Scope-only decode: just the first '_' is the scope separator.
 		pushCandidate(flat.replace('_', '/'));

diff --git a/packages/vite/hmr/server/websocket-module-specifiers.prebundle.spec.ts b/packages/vite/hmr/server/websocket-module-specifiers.prebundle.spec.ts
@@ -0,0 +1,24 @@
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+
+import { clearVendorManifest, registerVendorManifest } from '../shared/vendor/registry.js';
+import { viteDepsPathToBareSpecifier } from './websocket-module-specifiers.js';
+
+describe('viteDepsPathToBareSpecifier', () => {
+	beforeEach(() => {
+		registerVendorManifest({ hash: 'test', modules: { pkg: {}, '@scope/pkg': {} } } as any);
+	});
+	afterEach(() => clearVendorManifest());
+
+	it('decodes the dots in a subpath under a vendored package', () => {
+		expect(viteDepsPathToBareSpecifier('pkg_addons_env_file__js.js')).toBe('pkg/addons/env/file.js');
+	});
+
+	it('decodes an extensionless subpath and a scoped package', () => {
+		expect(viteDepsPathToBareSpecifier('pkg_examples_controls_orbit.js')).toBe('pkg/examples/controls/orbit');
+		expect(viteDepsPathToBareSpecifier('@scope_pkg_lib_x__min.js')).toBe('@scope/pkg/lib/x.min');
+	});
+
+	it('returns the package itself for its own prebundle', () => {
+		expect(viteDepsPathToBareSpecifier('pkg.js')).toBe('pkg');
+	});
+});
diff --git a/packages/vite/hmr/server/websocket-module-specifiers.ts b/packages/vite/hmr/server/websocket-module-specifiers.ts
@@ -27,6 +27,18 @@ export function extractVitePrebundleId(spec: string): string | null {
 	return null;
 }
 
+/**
+ * Reverses Vite's flattenId, which encodes '.' as '__' and '/' as '_'. The
+ * dots are split out first so `lib_file__js` decodes to `lib/file.js`, not
+ * `lib/file//js`. Lossy for names that themselves contain '_'.
+ */
+export function decodeFlattenedId(flat: string): string {
+	return flat
+		.split('__')
+		.map((segment) => segment.replace(/_/g, '/'))
+		.join('.');
+}
+
 export function getFlattenedManifestMap(manifest: VendorManifest): Map<string, string> {
 	const map = new Map<string, string>();
 	const mods = Object.keys(manifest.modules || {});
@@ -280,8 +292,7 @@ export function resolveVendorFromCandidate(specifier: string | null | undefined)
 				return canonical;
 			}
 			if (flattenedId.startsWith(`${flatKey}_`)) {
-				const flatSuffix = flattenedId.slice(flatKey.length + 1);
-				const subpath = flatSuffix.replace(/_/g, '/');
+				const subpath = decodeFlattenedId(flattenedId.slice(flatKey.length + 1));
 				if (isFileDistSubpath(subpath)) {
 					return canonical;
 				}
@@ -291,7 +302,7 @@ export function resolveVendorFromCandidate(specifier: string | null | undefined)
 				}
 			}
 		}
-		const guessedId = flattenedId.replace(/__/g, '.').replace(/_/g, '/');
+		const guessedId = decodeFlattenedId(flattenedId);
 		if (guessedId && guessedId !== flattenedId) {
 			const guessedCanonical = resolveVendorSpecifier(guessedId);
 			if (guessedCanonical) {
@@ -589,9 +600,7 @@ export function viteDepsPathToBareSpecifier(depPath: string): string | null {
 	}
 
 	if (bestKey && bestCanonical) {
-		const flatSuffix = flatId.slice(bestKey.length + 1);
-		const subpath = flatSuffix.replace(/_/g, '/');
-		return `${bestCanonical}/${subpath}`;
+		return `${bestCanonical}/${decodeFlattenedId(flatId.slice(bestKey.length + 1))}`;
 	}
 
 	return null;