fix(tools): Load original content before generating diff in background mode

Moved originalContent loading before diff generation to ensure proper diff comparison. Previously, the diff was being generated with empty originalContent, causing all lines to appear as additions.

Author: hannesrudolph

src/core/tools/writeToFileTool.ts

@@ -173,6 +173,15 @@ export async function writeToFileTool(
 
 			if (isPreventFocusDisruptionEnabled) {
 				// Direct file write without diff view
+				// Set up diffViewProvider properties needed for diff generation and saveDirectly
+				cline.diffViewProvider.editType = fileExists ? "modify" : "create"
+				if (fileExists) {
+					const absolutePath = path.resolve(cline.cwd, relPath)
+					cline.diffViewProvider.originalContent = await fs.readFile(absolutePath, "utf-8")
+				} else {
+					cline.diffViewProvider.originalContent = ""
+				}
+
 				// Check for code omissions before proceeding
 				if (detectCodeOmission(cline.diffViewProvider.originalContent || "", newContent, predictedLineCount)) {
 					if (cline.diffStrategy) {
@@ -216,15 +225,6 @@ export async function writeToFileTool(
 					return
 				}
 
-				// Set up diffViewProvider properties needed for saveDirectly
-				cline.diffViewProvider.editType = fileExists ? "modify" : "create"
-				if (fileExists) {
-					const absolutePath = path.resolve(cline.cwd, relPath)
-					cline.diffViewProvider.originalContent = await fs.readFile(absolutePath, "utf-8")
-				} else {
-					cline.diffViewProvider.originalContent = ""
-				}
-
 				// Save directly without showing diff view or opening the file
 				await cline.diffViewProvider.saveDirectly(relPath, newContent, false, diagnosticsEnabled, writeDelayMs)
 			} else {