fix(amazonq): diff not appearing for new files

Author: ctlai95

packages/amazonq/src/lsp/chat/messages.ts

@@ -452,7 +452,7 @@ export function registerMessageListeners(
                     activeFileContext: { filePath: params.originalFileUri },
                     focusAreaContext: { selectionInsideExtendedCodeBlock: entireDocumentSelection },
                 },
-                code: params.fileContent,
+                code: params.fileContent ?? '',
             },
             amazonQDiffScheme,
             true

packages/core/src/amazonq/commons/controllers/contentController.ts

@@ -161,7 +161,7 @@ export class EditorContentController {
         const { filePath, selection } = extractFileAndCodeSelectionFromMessage(message)
 
         try {
-            if (filePath && message?.code?.trim().length > 0 && selection) {
+            if (filePath && message?.code !== undefined && selection) {
                 const originalFileUri = vscode.Uri.file(filePath)
                 const uri = await createTempFileForDiff(originalFileUri, message, selection, scheme)