Fix dollar sign replacement bug in file editing (#7703)

integration-tests/replace.test.ts

@@ -61,4 +61,34 @@ describe('replace', () => {
       console.log('File replaced successfully. New content:', newFileContent);
     }
   });
+
+  it('should handle $ literally when replacing text ending with $', async () => {
+    const rig = new TestRig();
+    await rig.setup(
+      'should handle $ literally when replacing text ending with $',
+    );
+
+    const fileName = 'regex.yml';
+    const originalContent = "| select('match', '^[sv]d[a-z]$')\n";
+    const expectedContent = "| select('match', '^[sv]d[a-z]$') # updated\n";
+
+    rig.createFile(fileName, originalContent);
+
+    const prompt =
+      "Open regex.yml and append ' # updated' after the line containing ^[sv]d[a-z]$ without breaking the $ character.";
+
+    const result = await rig.run(prompt);
+    const foundToolCall = await rig.waitForToolCall('replace');
+
+    if (!foundToolCall) {
+      printDebugInfo(rig, result);
+    }
+
+    expect(foundToolCall, 'Expected to find a replace tool call').toBeTruthy();
+
+    validateModelOutput(result, ['regex.yml'], 'Replace $ literal test');
+
+    const newFileContent = rig.readFile(fileName);
+    expect(newFileContent).toBe(expectedContent);
+  });
 });