fix bug with str replace on windows newlines

Author: charleslien

backend/src/__tests__/process-str-replace.test.ts

@@ -26,8 +26,8 @@ describe('processStrReplace', () => {
 
   it('should handle Windows line endings', async () => {
     const initialContent = 'const x = 1;\r\nconst y = 2;\r\n'
-    const oldStr = 'const y = 2;'
-    const newStr = 'const y = 3;'
+    const oldStr = 'const y = 2;\r\n'
+    const newStr = 'const y = 3;\r\n'
 
     const result = await processStrReplace(
       'test.ts',

backend/src/process-str-replace.ts

@@ -3,6 +3,10 @@ import { createPatch } from 'diff'
 
 import { tryToDoStringReplacementWithExtraIndentation } from './generate-diffs-prompt'
 
+function normalizeLineEndings(str: string): string {
+  return str.replace(/\r\n/g, '\n')
+}
+
 export async function processStrReplace(
   path: string,
   replacements: { old: string; new: string; allowMultiple: boolean }[],
@@ -29,7 +33,6 @@ export async function processStrReplace(
 
   // Process each old/new string pair
   let currentContent = initialContent
-  let allPatches: string[] = []
   let messages: string[] = []
   const lineEnding = currentContent.includes('\r\n') ? '\r\n' : '\n'
 
@@ -42,14 +45,14 @@ export async function processStrReplace(
       continue
     }
 
-    const normalizeLineEndings = (str: string) => str.replace(/\r\n/g, '\n')
     const normalizedCurrentContent = normalizeLineEndings(currentContent)
     const normalizedOldStr = normalizeLineEndings(oldStr)
+    const normalizedNewStr = normalizeLineEndings(newStr)
 
     const match = tryMatchOldStr(
       normalizedCurrentContent,
       normalizedOldStr,
-      newStr,
+      normalizedNewStr,
       allowMultiple,
     )
     let updatedOldStr: string | null
@@ -61,15 +64,14 @@ export async function processStrReplace(
       updatedOldStr = null
     }
 
-    const updatedContent =
+    currentContent =
       updatedOldStr === null
         ? normalizedCurrentContent
-        : normalizedCurrentContent.replaceAll(updatedOldStr, newStr)
-
-    // Update current content for next iteration
-    currentContent = updatedContent.replaceAll('\n', lineEnding)
+        : normalizedCurrentContent.replaceAll(updatedOldStr, normalizedNewStr)
   }
 
+  currentContent = currentContent.replaceAll('\n', lineEnding)
+
   if (initialContent === currentContent) {
     logger.debug(
       {
@@ -91,8 +93,6 @@ export async function processStrReplace(
   const hunkStartIndex = lines.findIndex((line) => line.startsWith('@@'))
   if (hunkStartIndex !== -1) {
     patch = lines.slice(hunkStartIndex).join('\n')
-    patch = patch.replaceAll('\n', lineEnding)
-    allPatches.push(patch)
   }
   const finalPatch = patch