feat(chat): Improve diff appearance in main chat view

src/core/diff/stats.ts

@@ -0,0 +1,71 @@
+import { parsePatch, createTwoFilesPatch } from "diff"
+
+/**
+ * Diff utilities for backend (extension) use.
+ * Source of truth for diff normalization and stats.
+ */
+
+export interface DiffStats {
+	added: number
+	removed: number
+}
+
+/**
+ * Remove non-semantic diff noise like "No newline at end of file"
+ */
+export function sanitizeUnifiedDiff(diff: string): string {
+	if (!diff) return diff
+	return diff.replace(/\r\n/g, "\n").replace(/(^|\n)[ \t]*(?:\\ )?No newline at end of file[ \t]*(?=\n|$)/gi, "$1")
+}
+
+/**
+ * Compute +/− counts from a unified diff (ignores headers/hunk lines)
+ */
+export function computeUnifiedDiffStats(diff?: string): DiffStats | null {
+	if (!diff) return null
+
+	try {
+		const patches = parsePatch(diff)
+		if (!patches || patches.length === 0) return null
+
+		let added = 0
+		let removed = 0
+
+		for (const p of patches) {
+			for (const h of (p as any).hunks ?? []) {
+				for (const l of h.lines ?? []) {
+					const ch = (l as string)[0]
+					if (ch === "+") added++
+					else if (ch === "-") removed++
+				}
+			}
+		}
+
+		if (added > 0 || removed > 0) return { added, removed }
+		return { added: 0, removed: 0 }
+	} catch {
+		// If parsing fails for any reason, signal no stats
+		return null
+	}
+}
+
+/**
+ * Compute diff stats from any supported diff format (unified or search-replace)
+ * Tries unified diff format first, then falls back to search-replace format
+ */
+export function computeDiffStats(diff?: string): DiffStats | null {
+	if (!diff) return null
+	return computeUnifiedDiffStats(diff)
+}
+
+/**
+ * Build a unified diff for a brand new file (all content lines are additions).
+ * Trailing newline is ignored for line counting and emission.
+ */
+export function convertNewFileToUnifiedDiff(content: string, filePath?: string): string {
+	const newFileName = filePath || "file"
+	// Normalize EOLs; rely on library for unified patch formatting
+	const normalized = (content || "").replace(/\r\n/g, "\n")
+	// Old file is empty (/dev/null), new file has content; zero context to show all lines as additions
+	return createTwoFilesPatch("/dev/null", newFileName, "", normalized, undefined, undefined, { context: 0 })
+}

src/core/prompts/responses.ts

@@ -177,7 +177,9 @@ Otherwise, if you have not completed the task and do not need additional informa
 
 	createPrettyPatch: (filename = "file", oldStr?: string, newStr?: string) => {
 		// strings cannot be undefined or diff throws exception
-		const patch = diff.createPatch(filename.toPosix(), oldStr || "", newStr || "")
+		const patch = diff.createPatch(filename.toPosix(), oldStr || "", newStr || "", undefined, undefined, {
+			context: 3,
+		})
 		const lines = patch.split("\n")
 		const prettyPatchLines = lines.slice(4)
 		return prettyPatchLines.join("\n")

src/core/tools/applyDiffTool.ts

@@ -13,6 +13,7 @@ import { fileExistsAtPath } from "../../utils/fs"
 import { RecordSource } from "../context-tracking/FileContextTrackerTypes"
 import { unescapeHtmlEntities } from "../../utils/text-normalization"
 import { EXPERIMENT_IDS, experiments } from "../../shared/experiments"
+import { computeDiffStats, sanitizeUnifiedDiff } from "../diff/stats"
 
 export async function applyDiffToolLegacy(
 	cline: Task,
@@ -140,6 +141,11 @@ export async function applyDiffToolLegacy(
 			cline.consecutiveMistakeCount = 0
 			cline.consecutiveMistakeCountForApplyDiff.delete(relPath)
 
+			// Generate backend-unified diff for display in chat/webview
+			const unifiedPatchRaw = formatResponse.createPrettyPatch(relPath, originalContent, diffResult.content)
+			const unifiedPatch = sanitizeUnifiedDiff(unifiedPatchRaw)
+			const diffStats = computeDiffStats(unifiedPatch) || undefined
+
 			// Check if preventFocusDisruption experiment is enabled
 			const provider = cline.providerRef.deref()
 			const state = await provider?.getState()
@@ -158,6 +164,8 @@ export async function applyDiffToolLegacy(
 				const completeMessage = JSON.stringify({
 					...sharedMessageProps,
 					diff: diffContent,
+					content: unifiedPatch,
+					diffStats,
 					isProtected: isWriteProtected,
 				} satisfies ClineSayTool)
 
@@ -194,6 +202,8 @@ export async function applyDiffToolLegacy(
 				const completeMessage = JSON.stringify({
 					...sharedMessageProps,
 					diff: diffContent,
+					content: unifiedPatch,
+					diffStats,
 					isProtected: isWriteProtected,
 				} satisfies ClineSayTool)
 

src/core/tools/insertContentTool.ts

@@ -12,6 +12,7 @@ import { fileExistsAtPath } from "../../utils/fs"
 import { insertGroups } from "../diff/insert-groups"
 import { DEFAULT_WRITE_DELAY_MS } from "@roo-code/types"
 import { EXPERIMENT_IDS, experiments } from "../../shared/experiments"
+import { convertNewFileToUnifiedDiff, computeDiffStats, sanitizeUnifiedDiff } from "../diff/stats"
 
 export async function insertContentTool(
 	cline: Task,
@@ -101,7 +102,7 @@ export async function insertContentTool(
 		cline.diffViewProvider.originalContent = fileContent
 		const lines = fileExists ? fileContent.split("\n") : []
 
-		const updatedContent = insertGroups(lines, [
+		let updatedContent = insertGroups(lines, [
 			{
 				index: lineNumber - 1,
 				elements: content.split("\n"),
@@ -118,31 +119,31 @@ export async function insertContentTool(
 			EXPERIMENT_IDS.PREVENT_FOCUS_DISRUPTION,
 		)
 
-		// For consistency with writeToFileTool, handle new files differently
-		let diff: string | undefined
-		let approvalContent: string | undefined
-
+		// Build unified diff for display (normalize EOLs only for diff generation)
+		let unified: string
 		if (fileExists) {
-			// For existing files, generate diff and check for changes
-			diff = formatResponse.createPrettyPatch(relPath, fileContent, updatedContent)
-			if (!diff) {
+			const oldForDiff = fileContent.replace(/\r\n/g, "\n")
+			const newForDiff = updatedContent.replace(/\r\n/g, "\n")
+			unified = formatResponse.createPrettyPatch(relPath, oldForDiff, newForDiff)
+			if (!unified) {
 				pushToolResult(`No changes needed for '${relPath}'`)
 				return
 			}
-			approvalContent = undefined
 		} else {
-			// For new files, skip diff generation and provide full content
-			diff = undefined
-			approvalContent = updatedContent
+			const newForDiff = updatedContent.replace(/\r\n/g, "\n")
+			unified = convertNewFileToUnifiedDiff(newForDiff, relPath)
 		}
+		unified = sanitizeUnifiedDiff(unified)
+		const diffStats = computeDiffStats(unified) || undefined
 
 		// Prepare the approval message (same for both flows)
 		const completeMessage = JSON.stringify({
 			...sharedMessageProps,
-			diff,
-			content: approvalContent,
+			// Send unified diff as content for render-only webview
+			content: unified,
 			lineNumber: lineNumber,
 			isProtected: isWriteProtected,
+			diffStats,
 		} satisfies ClineSayTool)
 
 		// Show diff view if focus disruption prevention is disabled

src/core/tools/multiApplyDiffTool.ts

@@ -15,6 +15,7 @@ import { unescapeHtmlEntities } from "../../utils/text-normalization"
 import { parseXmlForDiff } from "../../utils/xml"
 import { EXPERIMENT_IDS, experiments } from "../../shared/experiments"
 import { applyDiffToolLegacy } from "./applyDiffTool"
+import { computeDiffStats, sanitizeUnifiedDiff } from "../diff/stats"
 
 interface DiffOperation {
 	path: string
@@ -282,31 +283,70 @@ Original error: ${errorMessage}`
 				(opResult) => cline.rooProtectedController?.isWriteProtected(opResult.path) || false,
 			)
 
-			// Prepare batch diff data
-			const batchDiffs = operationsToApprove.map((opResult) => {
+			// Stream batch diffs progressively for better UX
+			const batchDiffs: Array<{
+				path: string
+				changeCount: number
+				key: string
+				content: string
+				diffStats?: { added: number; removed: number }
+				diffs?: Array<{ content: string; startLine?: number }>
+			}> = []
+
+			for (const opResult of operationsToApprove) {
 				const readablePath = getReadablePath(cline.cwd, opResult.path)
 				const changeCount = opResult.diffItems?.length || 0
 				const changeText = changeCount === 1 ? "1 change" : `${changeCount} changes`
 
-				return {
+				let unified = ""
+				try {
+					const original = await fs.readFile(opResult.absolutePath!, "utf-8")
+					const processed = !cline.api.getModel().id.includes("claude")
+						? (opResult.diffItems || []).map((item) => ({
+								...item,
+								content: item.content ? unescapeHtmlEntities(item.content) : item.content,
+							}))
+						: opResult.diffItems || []
+
+					const applyRes =
+						(await cline.diffStrategy?.applyDiff(original, processed)) ?? ({ success: false } as any)
+					const newContent = applyRes.success && applyRes.content ? applyRes.content : original
+					unified = formatResponse.createPrettyPatch(opResult.path, original, newContent)
+				} catch {
+					unified = ""
+				}
+
+				const unifiedSanitized = sanitizeUnifiedDiff(unified)
+				const stats = computeDiffStats(unifiedSanitized) || undefined
+				batchDiffs.push({
 					path: readablePath,
 					changeCount,
 					key: `${readablePath} (${changeText})`,
-					content: opResult.path, // Full relative path
+					content: unifiedSanitized,
+					diffStats: stats,
 					diffs: opResult.diffItems?.map((item) => ({
 						content: item.content,
 						startLine: item.startLine,
 					})),
-				}
-			})
+				})
+
+				// Send a partial update after each file preview is ready
+				const partialMessage = JSON.stringify({
+					tool: "appliedDiff",
+					batchDiffs,
+					isProtected: hasProtectedFiles,
+				} satisfies ClineSayTool)
+				await cline.ask("tool", partialMessage, true).catch(() => {})
+			}
 
+			// Final approval message (non-partial)
 			const completeMessage = JSON.stringify({
 				tool: "appliedDiff",
 				batchDiffs,
 				isProtected: hasProtectedFiles,
 			} satisfies ClineSayTool)
 
-			const { response, text, images } = await cline.ask("tool", completeMessage, hasProtectedFiles)
+			const { response, text, images } = await cline.ask("tool", completeMessage, false)
 
 			// Process batch response
 			if (response === "yesButtonClicked") {
@@ -418,6 +458,7 @@ Original error: ${errorMessage}`
 
 			try {
 				let originalContent: string | null = await fs.readFile(absolutePath, "utf-8")
+				let beforeContent: string | null = originalContent
 				let successCount = 0
 				let formattedError = ""
 
@@ -540,9 +581,13 @@ ${errorDetails ? `\nTechnical details:\n${errorDetails}\n` : ""}
 				if (operationsToApprove.length === 1) {
 					// Prepare common data for single file operation
 					const diffContents = diffItems.map((item) => item.content).join("\n\n")
+					const unifiedPatchRaw = formatResponse.createPrettyPatch(relPath, beforeContent!, originalContent!)
+					const unifiedPatch = sanitizeUnifiedDiff(unifiedPatchRaw)
 					const operationMessage = JSON.stringify({
 						...sharedMessageProps,
 						diff: diffContents,
+						content: unifiedPatch,
+						diffStats: computeDiffStats(unifiedPatch) || undefined,
 					} satisfies ClineSayTool)
 
 					let toolProgressStatus

src/core/tools/writeToFileTool.ts

@@ -16,6 +16,7 @@ import { detectCodeOmission } from "../../integrations/editor/detect-omission"
 import { unescapeHtmlEntities } from "../../utils/text-normalization"
 import { DEFAULT_WRITE_DELAY_MS } from "@roo-code/types"
 import { EXPERIMENT_IDS, experiments } from "../../shared/experiments"
+import { convertNewFileToUnifiedDiff, computeDiffStats, sanitizeUnifiedDiff } from "../diff/stats"
 
 export async function writeToFileTool(
 	cline: Task,
@@ -173,6 +174,15 @@ 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) {
@@ -202,9 +212,15 @@ export async function writeToFileTool(
 					}
 				}
 
+				// Build unified diff for both existing and new files
+				let unified = fileExists
+					? formatResponse.createPrettyPatch(relPath, cline.diffViewProvider.originalContent, newContent)
+					: convertNewFileToUnifiedDiff(newContent, relPath)
+				unified = sanitizeUnifiedDiff(unified)
 				const completeMessage = JSON.stringify({
 					...sharedMessageProps,
-					content: newContent,
+					content: unified,
+					diffStats: computeDiffStats(unified) || undefined,
 				} satisfies ClineSayTool)
 
 				const didApprove = await askApproval("tool", completeMessage, undefined, isWriteProtected)
@@ -213,15 +229,6 @@ 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 {
@@ -275,12 +282,15 @@ export async function writeToFileTool(
 					}
 				}
 
+				// Build unified diff for both existing and new files
+				let unified = fileExists
+					? formatResponse.createPrettyPatch(relPath, cline.diffViewProvider.originalContent, newContent)
+					: convertNewFileToUnifiedDiff(newContent, relPath)
+				unified = sanitizeUnifiedDiff(unified)
 				const completeMessage = JSON.stringify({
 					...sharedMessageProps,
-					content: fileExists ? undefined : newContent,
-					diff: fileExists
-						? formatResponse.createPrettyPatch(relPath, cline.diffViewProvider.originalContent, newContent)
-						: undefined,
+					content: unified,
+					diffStats: computeDiffStats(unified) || undefined,
 				} satisfies ClineSayTool)
 
 				const didApprove = await askApproval("tool", completeMessage, undefined, isWriteProtected)