From f2292d2d19a066b37f78e03fa97d3cd0792e5586 Mon Sep 17 00:00:00 2001
From: Yufeng He <40085740+he-yufeng@users.noreply.github.com>
Date: Sat, 23 May 2026 23:54:26 +0800
Subject: [PATCH] fix: preserve literal dollars in filesystem edits

---
 src/filesystem/__tests__/lib.test.ts | 16 ++++++++++++++++
 src/filesystem/lib.ts                |  2 +-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/filesystem/__tests__/lib.test.ts b/src/filesystem/__tests__/lib.test.ts
index f7e585af22..a38a21fd8d 100644
--- a/src/filesystem/__tests__/lib.test.ts
+++ b/src/filesystem/__tests__/lib.test.ts
@@ -451,6 +451,22 @@ describe('Lib Functions', () => {
         expect(mockFs.writeFile).not.toHaveBeenCalled();
       });
 
+      it('treats dollar signs in replacement text literally', async () => {
+        const edits = [
+          { oldText: 'line2', newText: '$$100 $& value' }
+        ];
+
+        mockFs.rename.mockResolvedValueOnce(undefined);
+
+        await applyFileEdits('/test/file.txt', edits, false);
+
+        expect(mockFs.writeFile).toHaveBeenCalledWith(
+          expect.stringMatching(/\/test\/file\.txt\.[a-f0-9]+\.tmp$/),
+          'line1\n$$100 $& value\nline3\n',
+          'utf-8'
+        );
+      });
+
       it('applies multiple edits sequentially', async () => {
         const edits = [
           { oldText: 'line1', newText: 'first line' },
diff --git a/src/filesystem/lib.ts b/src/filesystem/lib.ts
index 17e4654cd5..ce4af9f38a 100644
--- a/src/filesystem/lib.ts
+++ b/src/filesystem/lib.ts
@@ -207,7 +207,7 @@ export async function applyFileEdits(
 
     // If exact match exists, use it
     if (modifiedContent.includes(normalizedOld)) {
-      modifiedContent = modifiedContent.replace(normalizedOld, normalizedNew);
+      modifiedContent = modifiedContent.replace(normalizedOld, () => normalizedNew);
       continue;
     }