feat: introduce experimental diff strategy toggle and enhance diff handling

- Added support for an experimental diff strategy in the Cline class, allowing users to opt for a new unified diff approach.
- Updated the getDiffStrategy function to accommodate the experimental strategy, adjusting the fuzzy match threshold accordingly.
- Integrated experimentalDiffStrategy into the global state management, enabling persistence across sessions.
- Enhanced the ClineProvider and related components to handle the new experimental strategy, including UI updates for user settings.
- Improved task history management to include the experimentalDiffStrategy setting, ensuring consistency in task execution.
- Updated relevant interfaces and types to reflect the new experimentalDiffStrategy property.

src/core/Cline.ts

@@ -51,6 +51,7 @@ import { detectCodeOmission } from "../integrations/editor/detect-omission"
 import { BrowserSession } from "../services/browser/BrowserSession"
 import { OpenRouterHandler } from "../api/providers/openrouter"
 import { McpHub } from "../services/mcp/McpHub"
+import crypto from "crypto"
 
 const cwd =
 	vscode.workspace.workspaceFolders?.map((folder) => folder.uri.fsPath).at(0) ?? path.join(os.homedir(), "Desktop") // may or may not exist but fs checking existence would immediately ask for permission which would be bad UX, need to come up with a better solution
@@ -105,26 +106,30 @@ export class Cline {
 		task?: string | undefined,
 		images?: string[] | undefined,
 		historyItem?: HistoryItem | undefined,
+		experimentalDiffStrategy?: boolean,
 	) {
-		this.providerRef = new WeakRef(provider)
+		this.taskId = crypto.randomUUID()
 		this.api = buildApiHandler(apiConfiguration)
 		this.terminalManager = new TerminalManager()
 		this.urlContentFetcher = new UrlContentFetcher(provider.context)
 		this.browserSession = new BrowserSession(provider.context)
-		this.diffViewProvider = new DiffViewProvider(cwd)
 		this.customInstructions = customInstructions
 		this.diffEnabled = enableDiff ?? false
-		if (this.diffEnabled && this.api.getModel().id) {
-			this.diffStrategy = getDiffStrategy(this.api.getModel().id, fuzzyMatchThreshold ?? 1.0)
-		}
+
+		// Prioritize experimentalDiffStrategy from history item if available
+		const effectiveExperimentalDiffStrategy = historyItem?.experimentalDiffStrategy ?? experimentalDiffStrategy
+		this.diffStrategy = getDiffStrategy(this.api.getModel().id, fuzzyMatchThreshold, effectiveExperimentalDiffStrategy)
+		this.diffViewProvider = new DiffViewProvider(cwd)
+		this.providerRef = new WeakRef(provider)
+
 		if (historyItem) {
 			this.taskId = historyItem.id
-			this.resumeTaskFromHistory()
-		} else if (task || images) {
-			this.taskId = Date.now().toString()
+		}
+
+		if (task || images) {
 			this.startTask(task, images)
-		} else {
-			throw new Error("Either historyItem or task/images must be provided")
+		} else if (historyItem) {
+			this.resumeTaskFromHistory()
 		}
 	}
 

src/core/diff/DiffStrategy.ts

@@ -7,10 +7,14 @@ import { NewUnifiedDiffStrategy } from './strategies/new-unified'
  * @param model The name of the model being used (e.g., 'gpt-4', 'claude-3-opus')
  * @returns The appropriate diff strategy for the model
  */
-export function getDiffStrategy(model: string, fuzzyMatchThreshold?: number): DiffStrategy {
-    // For now, return SearchReplaceDiffStrategy for all models
-    // This architecture allows for future optimizations based on model capabilities
-    return new NewUnifiedDiffStrategy()
+export function getDiffStrategy(model: string, fuzzyMatchThreshold?: number, experimentalDiffStrategy?: boolean): DiffStrategy {
+    if (experimentalDiffStrategy) {
+        // Use the fuzzyMatchThreshold with a minimum of 0.8 (80%)
+        const threshold = Math.max(fuzzyMatchThreshold ?? 1.0, 0.8)
+        return new NewUnifiedDiffStrategy(threshold)
+    }
+    // Default to the stable SearchReplaceDiffStrategy
+    return new SearchReplaceDiffStrategy()
 }
 
 export type { DiffStrategy }

src/core/webview/ClineProvider.ts

@@ -85,6 +85,7 @@ type GlobalStateKey =
 	| "mcpEnabled"
 	| "alwaysApproveResubmit"
 	| "requestDelaySeconds"
+	| "experimentalDiffStrategy"
 export const GlobalFileNames = {
 	apiConversationHistory: "api_conversation_history.json",
 	uiMessages: "ui_messages.json",
@@ -233,7 +234,8 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			apiConfiguration,
 			customInstructions,
 			diffEnabled,
-			fuzzyMatchThreshold
+			fuzzyMatchThreshold,
+			experimentalDiffStrategy
 		} = await this.getState()
 		
 		this.cline = new Cline(
@@ -243,7 +245,9 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			diffEnabled,
 			fuzzyMatchThreshold,
 			task,
-			images
+			images,
+			undefined,
+			experimentalDiffStrategy
 		)
 	}
 
@@ -253,7 +257,8 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			apiConfiguration,
 			customInstructions,
 			diffEnabled,
-			fuzzyMatchThreshold
+			fuzzyMatchThreshold,
+			experimentalDiffStrategy
 		} = await this.getState()
 		
 		this.cline = new Cline(
@@ -264,7 +269,8 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			fuzzyMatchThreshold,
 			undefined,
 			undefined,
-			historyItem
+			historyItem,
+			experimentalDiffStrategy
 		)
 	}
 
@@ -805,6 +811,10 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 						}
 						break
 					}
+					case "experimentalDiffStrategy":
+						await this.updateGlobalState("experimentalDiffStrategy", message.bool ?? false)
+						await this.postStateToWebview()
+						break
 				}
 			},
 			null,
@@ -1155,7 +1165,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 		uiMessagesFilePath: string
 		apiConversationHistory: Anthropic.MessageParam[]
 	}> {
-		const history = ((await this.getGlobalState("taskHistory")) as HistoryItem[] | undefined) || []
+		const history = (await this.getGlobalState("taskHistory") as HistoryItem[] | undefined) || []
 		const historyItem = history.find((item) => item.id === id)
 		if (historyItem) {
 			const taskDirPath = path.join(this.context.globalStorageUri.fsPath, "tasks", id)
@@ -1220,7 +1230,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 
 	async deleteTaskFromState(id: string) {
 		// Remove the task from history
-		const taskHistory = ((await this.getGlobalState("taskHistory")) as HistoryItem[]) || []
+		const taskHistory = (await this.getGlobalState("taskHistory") as HistoryItem[]) || []
 		const updatedTaskHistory = taskHistory.filter((task) => task.id !== id)
 		await this.updateGlobalState("taskHistory", updatedTaskHistory)
 
@@ -1256,6 +1266,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			mcpEnabled,
 			alwaysApproveResubmit,
 			requestDelaySeconds,
+			experimentalDiffStrategy,
 		} = await this.getState()
 		
 		const allowedCommands = vscode.workspace
@@ -1290,6 +1301,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			mcpEnabled: mcpEnabled ?? true,
 			alwaysApproveResubmit: alwaysApproveResubmit ?? false,
 			requestDelaySeconds: requestDelaySeconds ?? 5,
+			experimentalDiffStrategy: experimentalDiffStrategy ?? false,
 		}
 	}
 
@@ -1397,6 +1409,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			mcpEnabled,
 			alwaysApproveResubmit,
 			requestDelaySeconds,
+			experimentalDiffStrategy,
 		] = await Promise.all([
 			this.getGlobalState("apiProvider") as Promise<ApiProvider | undefined>,
 			this.getGlobalState("apiModelId") as Promise<string | undefined>,
@@ -1449,6 +1462,7 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			this.getGlobalState("mcpEnabled") as Promise<boolean | undefined>,
 			this.getGlobalState("alwaysApproveResubmit") as Promise<boolean | undefined>,
 			this.getGlobalState("requestDelaySeconds") as Promise<number | undefined>,
+			this.getGlobalState("experimentalDiffStrategy") as Promise<boolean | undefined>,
 		])
 
 		let apiProvider: ApiProvider
@@ -1545,16 +1559,25 @@ export class ClineProvider implements vscode.WebviewViewProvider {
 			mcpEnabled: mcpEnabled ?? true,
 			alwaysApproveResubmit: alwaysApproveResubmit ?? false,
 			requestDelaySeconds: requestDelaySeconds ?? 5,
+			experimentalDiffStrategy: experimentalDiffStrategy ?? false,
 		}
 	}
 
 	async updateTaskHistory(item: HistoryItem): Promise<HistoryItem[]> {
-		const history = ((await this.getGlobalState("taskHistory")) as HistoryItem[]) || []
+		const history = (await this.getGlobalState("taskHistory") as HistoryItem[] | undefined) || []
 		const existingItemIndex = history.findIndex((h) => h.id === item.id)
+		
+		// Ensure experimentalDiffStrategy is included from current settings if not already set
+		const { experimentalDiffStrategy } = await this.getState() ?? {}
+		const updatedItem = {
+			...item,
+			experimentalDiffStrategy: item.experimentalDiffStrategy ?? experimentalDiffStrategy
+		}
+
 		if (existingItemIndex !== -1) {
-			history[existingItemIndex] = item
+			history[existingItemIndex] = updatedItem
 		} else {
-			history.push(item)
+			history.push(updatedItem)
 		}
 		await this.updateGlobalState("taskHistory", history)
 		return history

src/shared/ExtensionMessage.ts

@@ -70,6 +70,7 @@ export interface ExtensionState {
 	writeDelayMs: number
 	terminalOutputLineLimit?: number
 	mcpEnabled: boolean
+	experimentalDiffStrategy?: boolean
 }
 
 export interface ClineMessage {

src/shared/HistoryItem.ts

@@ -7,4 +7,5 @@ export type HistoryItem = {
 	cacheWrites?: number
 	cacheReads?: number
 	totalCost: number
+	experimentalDiffStrategy?: boolean
 }

src/shared/WebviewMessage.ts

@@ -54,6 +54,7 @@ export interface WebviewMessage {
 		| "searchCommits"
 		| "alwaysApproveResubmit"
 		| "requestDelaySeconds"
+		| "experimentalDiffStrategy"
 	text?: string
 	disabled?: boolean
 	askResponse?: ClineAskResponse