From 4c9b5a0e47e0e741c19497ba33e6dba5c6f8b98b Mon Sep 17 00:00:00 2001
From: contactjawad <contact.jawaddd@gmail.com>
Date: Wed, 12 Aug 2026 20:37:37 +0500
Subject: [PATCH] fix(define): only match escaped dots in escapedDotRE so
 `$`-prefixed keys are replaced

escapedDotRE was /(?<!\\)\\./g, whose `.` is unescaped, so it matched a
backslash followed by any character. For a define key like `$FOO`, escapeRegex
produces `\$FOO`, and the replaceAll then rewrote `\$` to `\??\.`, producing the
pattern `\??\.FOO`, which never matches `$FOO`. The `pattern.test(code)`
pre-check was therefore false and the define was silently skipped.

Escape the dot so only an escaped literal dot is rewritten. Dotted keys like
`import.meta.env` are unaffected (both regexes yield `foo\??\.bar`), while
escaped metacharacters such as `\$` are now left intact.
---
 packages/vite/src/node/__tests__/plugins/define.spec.ts | 9 +++++++++
 packages/vite/src/node/plugins/define.ts                | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/vite/src/node/__tests__/plugins/define.spec.ts b/packages/vite/src/node/__tests__/plugins/define.spec.ts
index 0a061e5c83a098..209e14c2a607ca 100644
--- a/packages/vite/src/node/__tests__/plugins/define.spec.ts
+++ b/packages/vite/src/node/__tests__/plugins/define.spec.ts
@@ -90,6 +90,15 @@ describe('definePlugin (SSR dev)', () => {
     ).toBe(undefined)
   })
 
+  test('replaces define keys containing `$`', async () => {
+    const transform = await createJsDefinePluginTransform({
+      $FOO: JSON.stringify('bar'),
+    })
+    expect(await transform('export const x = $FOO;')).toBe(
+      'export const x = "bar";\n',
+    )
+  })
+
   test('replace import.meta.env when it is a invalid json', async () => {
     const transform = await createJsDefinePluginTransform({
       'import.meta.env.LEGACY': '__VITE_IS_LEGACY__',
diff --git a/packages/vite/src/node/plugins/define.ts b/packages/vite/src/node/plugins/define.ts
index 3b653265de1da4..0651b79c414e82 100644
--- a/packages/vite/src/node/plugins/define.ts
+++ b/packages/vite/src/node/plugins/define.ts
@@ -7,7 +7,7 @@ import { isHTMLRequest } from './html'
 
 const nonJsRe = /\.json(?:$|\?)/
 const isNonJsRequest = (request: string): boolean => nonJsRe.test(request)
-const escapedDotRE = /(?<!\\)\\./g
+const escapedDotRE = /(?<!\\)\\\./g
 
 export function definePlugin(config: ResolvedConfig): Plugin {
   const isBuild = config.command === 'build'