docs

evals/.gitignore

@@ -19,4 +19,6 @@ diff_editing/test_outputs/
 .cache
 
 # Python bytecode cache
-*__pycache__/
+*__pycache__/
+
+diff-edits/cases.zip

evals/cli/src/commands/runDiffEval.ts

@@ -14,6 +14,8 @@ interface RunDiffEvalOptions {
 	testPath: string
 	outputPath: string
 	replay: boolean
+	replayRunId?: string
+	diffApplyFile?: string
 	maxCases?: number
 }
 
@@ -56,6 +58,14 @@ export async function runDiffEvalHandler(options: RunDiffEvalOptions) {
 		args.push("--replay")
 	}
 
+	if (options.replayRunId) {
+		args.push("--replay-run-id", options.replayRunId)
+	}
+
+	if (options.diffApplyFile) {
+		args.push("--diff-apply-file", options.diffApplyFile)
+	}
+
 	if (options.verbose) {
 		args.push("--verbose")
 	}

evals/cli/src/index.ts

@@ -93,6 +93,8 @@ program
 	.option("--thinking-budget <tokens>", "Set the thinking tokens budget", "0")
 	.option("--parallel", "Run tests in parallel", false)
 	.option("--replay", "Run evaluation from a pre-recorded LLM output, skipping the API call", false)
+	.option("--replay-run-id <run_id>", "The ID of the run to replay from the database")
+	.option("--diff-apply-file <filename>", "The name of the diff apply file to use for the replay")
 	.option("-v, --verbose", "Enable verbose logging", false)
 	.action(async (options) => {
 		try {

evals/diff-edits/ClineWrapper.ts

@@ -9,6 +9,7 @@ import {
 	AssistantMessageContent,
 } from "./parsing/parse-assistant-message-06-06-25" // "../../src/core/assistant-message"
 import { constructNewFileContent as constructNewFileContentV1, constructNewFileContentV2 } from "./diff-apply/diff-06-06-25"
+import { constructNewFileContent as constructNewFileContentV2_1 } from "./diff-apply/diff-06-23-25"
 import { constructNewFileContent as constructNewFileContentV3 } from "../../src/core/assistant-message/diff" // this defaults to the new v1 when called
 
 type ParseAssistantMessageFn = (message: string) => AssistantMessageContent[]
@@ -21,6 +22,8 @@ const parsingFunctions: Record<string, ParseAssistantMessageFn> = {
 }
 
 const diffEditingFunctions: Record<string, ConstructNewFileContentFn> = {
+	"diff-06-06-25": constructNewFileContentV2,
+	"diff-06-23-25": constructNewFileContentV2_1,
 	constructNewFileContentV1: constructNewFileContentV1,
 	constructNewFileContentV2: constructNewFileContentV2,
 	constructNewFileContentV3: constructNewFileContentV3, // position invariant diff
@@ -151,6 +154,7 @@ export async function runSingleEvaluation(input: TestInput): Promise<TestResult>
 			diffEditFunction,
 			thinkingBudgetTokens,
 			originalDiffEditToolCallMessage,
+			diffApplyFile,
 		} = input
 
 		const requiredParams = {
@@ -176,7 +180,7 @@ export async function runSingleEvaluation(input: TestInput): Promise<TestResult>
 		}
 
 		const parseAssistantMessage = parsingFunctions[parsingFunction]
-		const constructNewFileContent = diffEditingFunctions[diffEditFunction]
+		const constructNewFileContent = diffEditingFunctions[diffApplyFile || diffEditFunction]
 
 		if (!parseAssistantMessage || !constructNewFileContent) {
 			return {

evals/diff-edits/README.md

@@ -63,9 +63,22 @@ For example, if we ask for 5 valid attempts per test case, the system will keep
 
 This way, if we're comparing two models and one gets a 10% success rate on its valid diff edit attempts, and another gets 90%, we have a much clearer picture of their actual diff-generating capabilities. It avoids muddying the waters with attempts where the model didn't even try to perform the specific action we're evaluating. This approach helps us isolate and measure the diff-editing skill more directly, despite the non-deterministic nature of these models.
 
-## Some known edge cases
+## Replays
 
-I noticed that some of the current conversation jsons in the `./cases` folder are a little big bogus. Here's a running list of these areas:
+You can also use the replay argument to replay a previous benchmark run. This is super useful for iterating on our diffing algorithms without having to re-run expensive and time-consuming LLM calls.
 
-- ~~What if the conversation json was using a model with a massive context window, like Google Gemini's 1M context window, and we're now re-rolling that case on a smaller context window model like claude 4 (200k) or grok-3 (128k)? It's def gonna fail, and we shouldn't just keep trying. We should have a smart system for selecting which cases we can use given the arguments passed in. For example, if we pass in claude and grok with `max cases = 2`, we shouldn't just pick the first two jsons in the folder. We should go through, use a tokenizer, and make sure it would fit with some padding like 20k tokens. Use tiktoken. 20k padding will be sufficient even though different models tokenize differently.~~
-- There are some weird jsons, where something weird happen, where essentially there's a fluke. Maybe the user was using an extremely dumb model that just hallucinated a fake filepath. Now when we try to reroll that case, we never get a valid case. This can easily be handled by making sure that the file is present before selecting that eval for testing. By "file is present" I mean, that file_contents is present in the eval. Additionally, we should in the streamlit dashboard show cases where getting a valid attempt is a challenge, so we can review those cases more easily and throw them out if they're bogus. Maybe a special tab/page in the dashboard for this purpose. Across all runs / cases, what the most consistently problematic cases are. Pop one open to see the case formatted json with all the user/assistant turns.
+When you run an evaluation, every detail is stored in the database—including the raw, unmodified output from the model. The replay feature takes advantage of this by pulling that raw output and feeding it into a *different* diffing algorithm. This lets you isolate the performance of the diffing logic itself. We can see if a new algorithm is better at applying the exact same set of diffs that a model generated in a previous run.
+
+This process is blazingly fast and free, as it completely bypasses the need to make new API calls. It ensures a true apples-to-apples comparison between diffing strategies, since the model's output—the "ground truth" for the evaluation—remains identical.
+
+Here’s an example of how you would replay a previous run with a new diffing algorithm:
+
+```shell
+cd evals && npm run diff-eval -- --replay-run-id 9902189e-63a8-4210-a4fc-fe59e2eaf2c2 --diff-apply-file diff-06-23-25 --verbose
+```
+
+In this command:
+-   `--replay-run-id` specifies the original run we want to use as our ground truth.
+-   `--diff-apply-file` tells the script to use the new diffing logic from the `diff-06-23-25.ts` file.
+
+The script will then create a new run in the database that mirrors the original, but with the results of applying the new diffing algorithm. This allows for a direct comparison in the dashboard, helping us quickly see which of our diffing strategies is the most robust.

evals/diff-edits/TestRunner.ts

@@ -1,4 +1,8 @@
 import { runSingleEvaluation, TestInput, TestResult } from "./ClineWrapper"
+import { parseAssistantMessageV2, AssistantMessageContent } from "./parsing/parse-assistant-message-06-06-25"
+import { constructNewFileContent as constructNewFileContentV2 } from "./diff-apply/diff-06-06-25"
+import { constructNewFileContent as constructNewFileContentV2_1 } from "./diff-apply/diff-06-23-25"
+import { constructNewFileContent as constructNewFileContentV3 } from "../../src/core/assistant-message/diff"
 import { basicSystemPrompt } from "./prompts/basicSystemPrompt-06-06-25"
 import { claude4SystemPrompt } from "./prompts/claude4SystemPrompt-06-06-25"
 import { formatResponse } from "./helpers"
@@ -18,6 +22,10 @@ import {
 	insertResult,
 	DatabaseClient,
 	CreateResultInput,
+	getResultsByRun,
+	getCaseById,
+	getFileByHash,
+	getBenchmarkRun,
 } from "./database"
 
 // Load environment variables from .env file
@@ -184,6 +192,78 @@ class NodeTestRunner {
 		log(isVerbose, `✓ Created ${this.caseIdMap.size} database case records`);
 	}
 
+	/**
+	 * Store replay result in database, copying original data but with new diffing results
+	 */
+	async storeReplayResultInDatabase(replayResult: TestResult, originalResult: any, testId: string, newCaseId: string): Promise<void> {
+		if (!this.currentRunId || !this.processingFunctionsHash) {
+			return; // Skip if database not initialized
+		}
+
+		try {
+			// Map error string to error enum (simple mapping)
+			const errorEnum = this.mapErrorToEnum(replayResult.error);
+
+			// Store diff edit content if available
+			let fileEditedHash: string | undefined;
+			if (replayResult.diffEdit) {
+				fileEditedHash = await upsertFile({
+					filepath: `diff-edit-${testId}`,
+					content: replayResult.diffEdit
+				});
+			}
+
+			// Calculate basic metrics from diff edit if available
+			let numEdits = 0;
+			let numLinesAdded = 0;
+			let numLinesDeleted = 0;
+			
+			if (replayResult.diffEdit) {
+				// Simple parsing to count edits - count SEARCH/REPLACE blocks
+				const searchBlocks = (replayResult.diffEdit.match(/------- SEARCH/g) || []).length;
+				numEdits = searchBlocks;
+				
+				// Count added/deleted lines (rough approximation)
+				const lines = replayResult.diffEdit.split('\n');
+				for (const line of lines) {
+					if (line.startsWith('+') && !line.startsWith('+++')) {
+						numLinesAdded++;
+					} else if (line.startsWith('-') && !line.startsWith('---')) {
+						numLinesDeleted++;
+					}
+				}
+			}
+
+			// Copy original result data but update replay-specific fields
+			const resultInput: CreateResultInput = {
+				run_id: this.currentRunId, // New run ID
+				case_id: newCaseId, // New case ID
+				model_id: originalResult.model_id, // Copy from original
+				processing_functions_hash: this.processingFunctionsHash, // New processing functions
+				succeeded: replayResult.success && (replayResult.diffEditSuccess ?? false), // New result
+				error_enum: errorEnum, // New error if any
+				num_edits: numEdits || originalResult.num_edits, // New or original
+				num_lines_deleted: numLinesDeleted || originalResult.num_lines_deleted, // New or original
+				num_lines_added: numLinesAdded || originalResult.num_lines_added, // New or original
+				// Copy timing and cost data from original (since we didn't make API calls)
+				time_to_first_token_ms: originalResult.time_to_first_token_ms,
+				time_to_first_edit_ms: originalResult.time_to_first_edit_ms,
+				time_round_trip_ms: originalResult.time_round_trip_ms,
+				cost_usd: originalResult.cost_usd,
+				completion_tokens: originalResult.completion_tokens,
+				// Use original model output (since we're replaying)
+				raw_model_output: originalResult.raw_model_output,
+				file_edited_hash: fileEditedHash || originalResult.file_edited_hash,
+				parsed_tool_call_json: replayResult.toolCalls ? JSON.stringify(replayResult.toolCalls) : originalResult.parsed_tool_call_json
+			};
+
+			await insertResult(resultInput);
+		} catch (error) {
+			console.error(`Failed to store replay result in database for ${testId}:`, error);
+			// Continue execution - don't fail the test run
+		}
+	}
+
 	/**
 	 * Store test result in database
 	 */
@@ -394,6 +474,142 @@ class NodeTestRunner {
 		}
 	}
 
+	async runDatabaseReplay(replayRunId: string, diffApplyFile: string, isVerbose: boolean) {
+		log(isVerbose, `Starting database replay for run_id: ${replayRunId}`)
+		log(isVerbose, `Using diff apply file: ${diffApplyFile}`)
+
+		// 1. Get the correct diffing function
+		const diffEditingFunctions: Record<string, any> = {
+			"diff-06-06-25": constructNewFileContentV2,
+			"diff-06-23-25": constructNewFileContentV2_1,
+			constructNewFileContentV3: constructNewFileContentV3,
+		}
+		const constructNewFileContent = diffEditingFunctions[diffApplyFile]
+
+		if (!constructNewFileContent) {
+			throw new Error(`Could not find diff apply function for: ${diffApplyFile}`)
+		}
+		log(isVerbose, `Successfully loaded diff apply function: ${diffApplyFile}`)
+
+		// 2. Fetch original run data
+		const originalResults = await getResultsByRun(replayRunId)
+		if (originalResults.length === 0) {
+			throw new Error(`No results found for run_id: ${replayRunId}`)
+		}
+		log(isVerbose, `Found ${originalResults.length} results to replay.`)
+
+		const originalRun = await getBenchmarkRun(replayRunId)
+		if (!originalRun) {
+			throw new Error(`Could not find original run with id ${replayRunId}`)
+		}
+
+		// 3. Create a new benchmark run for the replay
+		const replayRunDescription = `Replay of run ${replayRunId} using ${diffApplyFile}`
+		this.currentRunId = await createBenchmarkRun({
+			description: replayRunDescription,
+			system_prompt_hash: originalRun.system_prompt_hash,
+		})
+		log(isVerbose, `Created new run for replay: ${this.currentRunId}`)
+
+		// 4. Set up processing functions for the new run
+		this.processingFunctionsHash = await upsertProcessingFunctions({
+			name: `replay-${diffApplyFile}`,
+			parsing_function: "parseAssistantMessageV2",
+			diff_edit_function: diffApplyFile,
+		})
+
+		// 5. Process each result from the original run
+		let replayedCount = 0
+		const caseIdMirror: Map<string, string> = new Map()
+
+		for (const originalResult of originalResults) {
+			// 5a. Basic validation to ensure we can even process this
+			if (!originalResult.case_id) {
+				log(isVerbose, `Skipping result ${originalResult.result_id} due to missing case_id.`)
+				continue
+			}
+
+			// 5b. Mirror the case for the new run, reusing if already created
+			let newCaseId = caseIdMirror.get(originalResult.case_id)
+			if (!newCaseId) {
+				const originalCase = await getCaseById(originalResult.case_id)
+				if (!originalCase) {
+					log(isVerbose, `Skipping result ${originalResult.result_id} because original case could not be found.`)
+					continue
+				}
+				newCaseId = await createCase({
+					run_id: this.currentRunId,
+					description: `Replay of case ${originalCase.case_id} from run ${replayRunId}`,
+					system_prompt_hash: originalCase.system_prompt_hash,
+					task_id: originalCase.task_id,
+					tokens_in_context: originalCase.tokens_in_context,
+					file_hash: originalCase.file_hash,
+				})
+				caseIdMirror.set(originalResult.case_id, newCaseId)
+			}
+
+			// 5c. Determine if the original attempt was a "valid attempt"
+			const isValidOriginalAttempt = originalResult.error_enum === null || originalResult.error_enum === 3 // 3 is diff_edit_error
+
+			const newResultInput: CreateResultInput = {
+				...(originalResult as any),
+				run_id: this.currentRunId,
+				case_id: newCaseId,
+				processing_functions_hash: this.processingFunctionsHash,
+			}
+			delete (newResultInput as any).result_id
+
+			if (isValidOriginalAttempt) {
+				// This was a valid attempt. Re-run the diff algorithm.
+				const originalCase = await getCaseById(originalResult.case_id)
+				if (!originalCase) {
+					log(isVerbose, `  [WARN] Replay for result ${originalResult.result_id}: Could not find original case. Copying original result.`)
+					newResultInput.succeeded = originalResult.succeeded
+					newResultInput.error_enum = originalResult.error_enum
+				} else {
+					const originalFile = originalCase.file_hash ? await getFileByHash(originalCase.file_hash) : null
+					const parsedToolCall = originalResult.parsed_tool_call_json ? JSON.parse(originalResult.parsed_tool_call_json)[0] : null
+					const diffContent = parsedToolCall?.input?.diff
+
+					if (originalFile && diffContent) {
+						let diffSuccess = false
+						try {
+							await constructNewFileContent(diffContent, originalFile.content, true)
+							diffSuccess = true
+							log(isVerbose, `  [OK] Replay for task ${originalCase.task_id}: Diff applied successfully.`)
+						} catch (e) {
+							diffSuccess = false
+							log(isVerbose, `  [FAIL] Replay for task ${originalCase.task_id}: New diff algorithm failed.`)
+						}
+						newResultInput.succeeded = diffSuccess
+						newResultInput.error_enum = diffSuccess ? undefined : 3 // 3 = diff_edit_error
+					} else {
+						// Something is wrong with the ground truth data, just copy it.
+						log(
+							isVerbose,
+							`  [WARN] Replay for task ${originalCase.task_id}: Valid original attempt but missing file or diff content. Copying original result.`,
+						)
+						newResultInput.succeeded = originalResult.succeeded
+						newResultInput.error_enum = originalResult.error_enum
+					}
+				}
+			} else {
+				// This was not a valid attempt. Just copy the original result's outcome.
+				log(isVerbose, `  [SKIP] Replay for task ${originalResult.case_id}: Invalid original attempt. Copying original result.`)
+				newResultInput.succeeded = originalResult.succeeded
+				newResultInput.error_enum = originalResult.error_enum
+			}
+
+			await insertResult(newResultInput)
+			replayedCount++
+		}
+
+		log(isVerbose, `\n✓ Database replay completed successfully.`)
+		log(isVerbose, `  Total original results: ${originalResults.length}`)
+		log(isVerbose, `  Total replayed results: ${replayedCount}`)
+		log(isVerbose, `  New run ID: ${this.currentRunId}`)
+	}
+
 	/**
 	 * Run a single test example
 	 */
@@ -420,6 +636,7 @@ class NodeTestRunner {
 			diffEditFunction: testConfig.diff_edit_function,
 			thinkingBudgetTokens: testConfig.thinking_tokens_budget,
 			originalDiffEditToolCallMessage: testConfig.replay ? testCase.original_diff_edit_tool_call_message : undefined,
+			diffApplyFile: testConfig.diff_apply_file,
 		}
 
 		if (isVerbose) {
@@ -712,6 +929,8 @@ async function main() {
 		.option("--thinking-budget <tokens>", "Set the thinking tokens budget", "0")
 		.option("--parallel", "Run tests in parallel", false)
 		.option("--replay", "Run evaluation from a pre-recorded LLM output, skipping the API call", false)
+		.option("--replay-run-id <run_id>", "The ID of the run to replay from the database")
+		.option("--diff-apply-file <filename>", "The name of the diff apply file to use for the replay")
 		.option("-v, --verbose", "Enable verbose logging", false)
 		.option("--max-concurrency <number>", "Maximum number of parallel requests", "80")
 
@@ -732,6 +951,17 @@ async function main() {
 	}
 
 	const validAttemptsPerCase = parseInt(options.validAttemptsPerCase, 10);
+
+	const runner = new NodeTestRunner(options.replay || !!options.replayRunId)
+
+	if (options.replayRunId) {
+		if (!options.diffApplyFile) {
+			console.error("Error: --diff-apply-file is required when using --replay-run-id")
+			process.exit(1)
+		}
+		await runner.runDatabaseReplay(options.replayRunId, options.diffApplyFile, isVerbose)
+		return
+	}
 	
 	try {
 		const startTime = Date.now()

evals/diff-edits/database.md

@@ -33,7 +33,7 @@ This is the most granular and important table in the database. A `result` repres
 
 -   **Purpose**: To store the detailed outcome of every single model attempt, providing the raw data for all quantitative and qualitative analysis.
 -   **Key Columns**:
-    -   `result_id`: A unique identifier for the individual attempt.
+    -   `result_id`: The primary key for the result.
     -   `run_id`, `case_id`, `model_id`, `processing_functions_hash`: A set of foreign keys that precisely situate this result within the context of a specific run, case, model, and set of helper functions.
     -   `succeeded`: A boolean indicating if the generated diff was applied successfully.
     -   `error_enum`: A numeric code representing the specific type of error if the attempt failed (e.g., `1` for `no_tool_calls`, `7` for `wrong_file_edited`).
@@ -82,3 +82,15 @@ This relational schema provides a powerful foundation for sophisticated analysis
 -   "Which of our internal diffing algorithms is the most robust against a wide range of model-generated edits?"
 
 Ultimately, this data model enables us to move from simply *measuring* performance to truly *understanding* it, providing the insights needed to build more capable and reliable AI engineering systems.
+
+---
+
+## Viewing the Full Schema
+
+To see the most up-to-date and detailed schema for the database, you can use the `sqlite3` command-line tool. From the `evals/diff-edits` directory, run the following command:
+
+```bash
+sqlite3 evals.db .schema
+```
+
+This will print the complete `CREATE TABLE` statements for all tables in the database, providing a definitive reference for the database structure.

evals/diff-edits/diff-apply/diff-06-23-25.ts

@@ -0,0 +1,827 @@
+const SEARCH_BLOCK_START = "------- SEARCH"
+const SEARCH_BLOCK_END = "======="
+const REPLACE_BLOCK_END = "+++++++ REPLACE"
+
+const SEARCH_BLOCK_CHAR = "-"
+const REPLACE_BLOCK_CHAR = "+"
+const LEGACY_SEARCH_BLOCK_CHAR = "<"
+const LEGACY_REPLACE_BLOCK_CHAR = ">"
+
+// Replace the exact string constants with flexible regex patterns
+const SEARCH_BLOCK_START_REGEX = /^[-]{3,} SEARCH$/
+const SEARCH_BLOCK_END_REGEX = /^[=]{3,}$/
+const REPLACE_BLOCK_END_REGEX = /^[+]{3,} REPLACE$/
+const LEGACY_SEARCH_BLOCK_START_REGEX = /^[<]{3,} SEARCH$/
+const LEGACY_REPLACE_BLOCK_END_REGEX = /^[>]{3,} REPLACE$/
+
+// Helper functions to check if a line matches the flexible patterns
+function isSearchBlockStart(line: string): boolean {
+	return SEARCH_BLOCK_START_REGEX.test(line) || LEGACY_SEARCH_BLOCK_START_REGEX.test(line)
+}
+
+function isSearchBlockEnd(line: string): boolean {
+	return SEARCH_BLOCK_END_REGEX.test(line)
+}
+
+function isReplaceBlockEnd(line: string): boolean {
+	return REPLACE_BLOCK_END_REGEX.test(line) || LEGACY_REPLACE_BLOCK_END_REGEX.test(line)
+}
+
+/**
+ * Attempts a line-trimmed fallback match for the given search content in the original content.
+ * It tries to match `searchContent` lines against a block of lines in `originalContent` starting
+ * from `lastProcessedIndex`. Lines are matched by trimming leading/trailing whitespace and ensuring
+ * they are identical afterwards.
+ *
+ * Returns [matchIndexStart, matchIndexEnd] if found, or false if not found.
+ */
+function lineTrimmedFallbackMatch(originalContent: string, searchContent: string, startIndex: number): [number, number] | false {
+	// Split both contents into lines
+	const originalLines = originalContent.split("\n")
+	const searchLines = searchContent.split("\n")
+
+	// Trim trailing empty line if exists (from the trailing \n in searchContent)
+	if (searchLines[searchLines.length - 1] === "") {
+		searchLines.pop()
+	}
+
+	// Find the line number where startIndex falls
+	let startLineNum = 0
+	let currentIndex = 0
+	while (currentIndex < startIndex && startLineNum < originalLines.length) {
+		currentIndex += originalLines[startLineNum].length + 1 // +1 for \n
+		startLineNum++
+	}
+
+	// For each possible starting position in original content
+	for (let i = startLineNum; i <= originalLines.length - searchLines.length; i++) {
+		let matches = true
+
+		// Try to match all search lines from this position
+		for (let j = 0; j < searchLines.length; j++) {
+			const originalTrimmed = originalLines[i + j].trim()
+			const searchTrimmed = searchLines[j].trim()
+
+			if (originalTrimmed !== searchTrimmed) {
+				matches = false
+				break
+			}
+		}
+
+		// If we found a match, calculate the exact character positions
+		if (matches) {
+			// Find start character index
+			let matchStartIndex = 0
+			for (let k = 0; k < i; k++) {
+				matchStartIndex += originalLines[k].length + 1 // +1 for \n
+			}
+
+			// Find end character index
+			let matchEndIndex = matchStartIndex
+			for (let k = 0; k < searchLines.length; k++) {
+				matchEndIndex += originalLines[i + k].length + 1 // +1 for \n
+			}
+
+			return [matchStartIndex, matchEndIndex]
+		}
+	}
+
+	return false
+}
+
+/**
+ * Attempts to match blocks of code by using the first and last lines as anchors.
+ * This is a third-tier fallback strategy that helps match blocks where we can identify
+ * the correct location by matching the beginning and end, even if the exact content
+ * differs slightly.
+ *
+ * The matching strategy:
+ * 1. Only attempts to match blocks of 3 or more lines to avoid false positives
+ * 2. Extracts from the search content:
+ *    - First line as the "start anchor"
+ *    - Last line as the "end anchor"
+ * 3. For each position in the original content:
+ *    - Checks if the next line matches the start anchor
+ *    - If it does, jumps ahead by the search block size
+ *    - Checks if that line matches the end anchor
+ *    - All comparisons are done after trimming whitespace
+ *
+ * This approach is particularly useful for matching blocks of code where:
+ * - The exact content might have minor differences
+ * - The beginning and end of the block are distinctive enough to serve as anchors
+ * - The overall structure (number of lines) remains the same
+ *
+ * @param originalContent - The full content of the original file
+ * @param searchContent - The content we're trying to find in the original file
+ * @param startIndex - The character index in originalContent where to start searching
+ * @returns A tuple of [startIndex, endIndex] if a match is found, false otherwise
+ */
+function blockAnchorFallbackMatch(originalContent: string, searchContent: string, startIndex: number): [number, number] | false {
+	const originalLines = originalContent.split("\n")
+	const searchLines = searchContent.split("\n")
+
+	// Only use this approach for blocks of 3+ lines
+	if (searchLines.length < 3) {
+		return false
+	}
+
+	// Trim trailing empty line if exists
+	if (searchLines[searchLines.length - 1] === "") {
+		searchLines.pop()
+	}
+
+	const firstLineSearch = searchLines[0].trim()
+	const lastLineSearch = searchLines[searchLines.length - 1].trim()
+	const searchBlockSize = searchLines.length
+
+	// Find the line number where startIndex falls
+	let startLineNum = 0
+	let currentIndex = 0
+	while (currentIndex < startIndex && startLineNum < originalLines.length) {
+		currentIndex += originalLines[startLineNum].length + 1
+		startLineNum++
+	}
+
+	// Look for matching start and end anchors
+	for (let i = startLineNum; i <= originalLines.length - searchBlockSize; i++) {
+		// Check if first line matches
+		if (originalLines[i].trim() !== firstLineSearch) {
+			continue
+		}
+
+		// Check if last line matches at the expected position
+		if (originalLines[i + searchBlockSize - 1].trim() !== lastLineSearch) {
+			continue
+		}
+
+		// Calculate exact character positions
+		let matchStartIndex = 0
+		for (let k = 0; k < i; k++) {
+			matchStartIndex += originalLines[k].length + 1
+		}
+
+		let matchEndIndex = matchStartIndex
+		for (let k = 0; k < searchBlockSize; k++) {
+			matchEndIndex += originalLines[i + k].length + 1
+		}
+
+		return [matchStartIndex, matchEndIndex]
+	}
+
+	return false
+}
+
+/**
+ * This function reconstructs the file content by applying a streamed diff (in a
+ * specialized SEARCH/REPLACE block format) to the original file content. It is designed
+ * to handle both incremental updates and the final resulting file after all chunks have
+ * been processed.
+ *
+ * The diff format is a custom structure that uses three markers to define changes:
+ *
+ *   ------- SEARCH
+ *   [Exact content to find in the original file]
+ *   =======
+ *   [Content to replace with]
+ *   +++++++ REPLACE
+ *
+ * Behavior and Assumptions:
+ * 1. The file is processed chunk-by-chunk. Each chunk of `diffContent` may contain
+ *    partial or complete SEARCH/REPLACE blocks. By calling this function with each
+ *    incremental chunk (with `isFinal` indicating the last chunk), the final reconstructed
+ *    file content is produced.
+ *
+ * 2. Matching Strategy (in order of attempt):
+ *    a. Exact Match: First attempts to find the exact SEARCH block text in the original file
+ *    b. Line-Trimmed Match: Falls back to line-by-line comparison ignoring leading/trailing whitespace
+ *    c. Block Anchor Match: For blocks of 3+ lines, tries to match using first/last lines as anchors
+ *    If all matching strategies fail, an error is thrown.
+ *
+ * 3. Empty SEARCH Section:
+ *    - If SEARCH is empty and the original file is empty, this indicates creating a new file
+ *      (pure insertion).
+ *    - If SEARCH is empty and the original file is not empty, this indicates a complete
+ *      file replacement (the entire original content is considered matched and replaced).
+ *
+ * 4. Applying Changes:
+ *    - Before encountering the "=======" marker, lines are accumulated as search content.
+ *    - After "=======" and before ">>>>>>> REPLACE", lines are accumulated as replacement content.
+ *    - Once the block is complete (">>>>>>> REPLACE"), the matched section in the original
+ *      file is replaced with the accumulated replacement lines, and the position in the original
+ *      file is advanced.
+ *
+ * 5. Incremental Output:
+ *    - As soon as the match location is found and we are in the REPLACE section, each new
+ *      replacement line is appended to the result so that partial updates can be viewed
+ *      incrementally.
+ *
+ * 6. Partial Markers:
+ *    - If the final line of the chunk looks like it might be part of a marker but is not one
+ *      of the known markers, it is removed. This prevents incomplete or partial markers
+ *      from corrupting the output.
+ *
+ * 7. Finalization:
+ *    - Once all chunks have been processed (when `isFinal` is true), any remaining original
+ *      content after the last replaced section is appended to the result.
+ *    - Trailing newlines are not forcibly added. The code tries to output exactly what is specified.
+ *
+ * Errors:
+ * - If the search block cannot be matched using any of the available matching strategies,
+ *   an error is thrown.
+ */
+export async function constructNewFileContent(
+	diffContent: string,
+	originalContent: string,
+	isFinal: boolean,
+	version: "v1" | "v2" = "v1",
+): Promise<string> {
+	const constructor = constructNewFileContentVersionMapping[version]
+	if (!constructor) {
+		throw new Error(`Invalid version '${version}' for file content constructor`)
+	}
+	return constructor(diffContent, originalContent, isFinal)
+}
+
+const constructNewFileContentVersionMapping: Record<
+	string,
+	(diffContent: string, originalContent: string, isFinal: boolean) => Promise<string>
+> = {
+	v1: constructNewFileContentV1,
+	v2: constructNewFileContentV2,
+} as const
+
+async function constructNewFileContentV1(diffContent: string, originalContent: string, isFinal: boolean): Promise<string> {
+	let result = ""
+	let lastProcessedIndex = 0
+
+	let currentSearchContent = ""
+	let currentReplaceContent = ""
+	let inSearch = false
+	let inReplace = false
+
+	let searchMatchIndex = -1
+	let searchEndIndex = -1
+
+	// Track all replacements to handle out-of-order edits
+	let replacements: Array<{ start: number; end: number; content: string }> = []
+	let pendingOutOfOrderReplacement = false
+
+	let lines = diffContent.split("\n")
+
+	// If the last line looks like a partial marker but isn't recognized,
+	// remove it because it might be incomplete.
+	const lastLine = lines[lines.length - 1]
+	if (
+		lines.length > 0 &&
+		(lastLine.startsWith(SEARCH_BLOCK_CHAR) ||
+			lastLine.startsWith(LEGACY_SEARCH_BLOCK_CHAR) ||
+			lastLine.startsWith("=") ||
+			lastLine.startsWith(REPLACE_BLOCK_CHAR) ||
+			lastLine.startsWith(LEGACY_REPLACE_BLOCK_CHAR)) &&
+		!isSearchBlockStart(lastLine) &&
+		!isSearchBlockEnd(lastLine) &&
+		!isReplaceBlockEnd(lastLine)
+	) {
+		lines.pop()
+	}
+
+	for (const line of lines) {
+		if (isSearchBlockStart(line)) {
+			inSearch = true
+			currentSearchContent = ""
+			currentReplaceContent = ""
+			continue
+		}
+
+		if (isSearchBlockEnd(line)) {
+			inSearch = false
+			inReplace = true
+
+			// Remove trailing linebreak for adding the === marker
+			// if (currentSearchContent.endsWith("\r\n")) {
+			// 	currentSearchContent = currentSearchContent.slice(0, -2)
+			// } else if (currentSearchContent.endsWith("\n")) {
+			// 	currentSearchContent = currentSearchContent.slice(0, -1)
+			// }
+
+			if (!currentSearchContent) {
+				// Empty search block
+				if (originalContent.length === 0) {
+					// New file scenario: nothing to match, just start inserting
+					searchMatchIndex = 0
+					searchEndIndex = 0
+				} else {
+					// ERROR: Empty search block with non-empty file indicates malformed SEARCH marker
+					throw new Error(
+						"Empty SEARCH block detected with non-empty file. This usually indicates a malformed SEARCH marker.\n" +
+							"Please ensure your SEARCH marker follows the correct format:\n" +
+							"- Use '------- SEARCH' (7+ dashes + space + SEARCH)\n",
+					)
+				}
+			} else {
+				// Add check for inefficient full-file search
+				// if (currentSearchContent.trim() === originalContent.trim()) {
+				// 	throw new Error(
+				// 		"The SEARCH block contains the entire file content. Please either:\n" +
+				// 			"1. Use an empty SEARCH block to replace the entire file, or\n" +
+				// 			"2. Make focused changes to specific parts of the file that need modification.",
+				// 	)
+				// }
+
+				// Exact search match scenario
+				const exactIndex = originalContent.indexOf(currentSearchContent, lastProcessedIndex)
+				if (exactIndex !== -1) {
+					searchMatchIndex = exactIndex
+					searchEndIndex = exactIndex + currentSearchContent.length
+				} else {
+					// Attempt fallback line-trimmed matching
+					const lineMatch = lineTrimmedFallbackMatch(originalContent, currentSearchContent, lastProcessedIndex)
+					if (lineMatch) {
+						;[searchMatchIndex, searchEndIndex] = lineMatch
+					} else {
+						// Try block anchor fallback for larger blocks
+						const blockMatch = blockAnchorFallbackMatch(originalContent, currentSearchContent, lastProcessedIndex)
+						if (blockMatch) {
+							;[searchMatchIndex, searchEndIndex] = blockMatch
+						} else {
+							// Last resort: search the entire file from the beginning
+							const fullFileIndex = originalContent.indexOf(currentSearchContent, 0)
+							if (fullFileIndex !== -1) {
+								// Found in the file - could be out of order
+								searchMatchIndex = fullFileIndex
+								searchEndIndex = fullFileIndex + currentSearchContent.length
+								if (searchMatchIndex < lastProcessedIndex) {
+									pendingOutOfOrderReplacement = true
+								}
+							} else {
+								throw new Error(
+									`The SEARCH block:\n${currentSearchContent.trimEnd()}\n...does not match anything in the file.`,
+								)
+							}
+						}
+					}
+				}
+			}
+
+			// Check if this is an out-of-order replacement
+			if (searchMatchIndex < lastProcessedIndex) {
+				pendingOutOfOrderReplacement = true
+			}
+
+			// For in-order replacements, output everything up to the match location
+			if (!pendingOutOfOrderReplacement) {
+				result += originalContent.slice(lastProcessedIndex, searchMatchIndex)
+			}
+			continue
+		}
+
+		if (isReplaceBlockEnd(line)) {
+			// Finished one replace block
+
+			// Store this replacement
+			replacements.push({
+				start: searchMatchIndex,
+				end: searchEndIndex,
+				content: currentReplaceContent,
+			})
+
+			// If this was an in-order replacement, advance lastProcessedIndex
+			if (!pendingOutOfOrderReplacement) {
+				lastProcessedIndex = searchEndIndex
+			}
+
+			// Reset for next block
+			inSearch = false
+			inReplace = false
+			currentSearchContent = ""
+			currentReplaceContent = ""
+			searchMatchIndex = -1
+			searchEndIndex = -1
+			pendingOutOfOrderReplacement = false
+			continue
+		}
+
+		// Accumulate content for search or replace
+		// (currentReplaceContent is not being used for anything right now since we directly append to result.)
+		// (We artificially add a linebreak since we split on \n at the beginning. In order to not include a trailing linebreak in the final search/result blocks we need to remove it before using them. This allows for partial line matches to be correctly identified.)
+		// NOTE: search/replace blocks must be arranged in the order they appear in the file due to how we build the content using lastProcessedIndex. We also cannot strip the trailing newline since for non-partial lines it would remove the linebreak from the original content. (If we remove end linebreak from search, then we'd also have to remove it from replace but we can't know if it's a partial line or not since the model may be using the line break to indicate the end of the block rather than as part of the search content.) We require the model to output full lines in order for our fallbacks to work as well.
+		if (inSearch) {
+			currentSearchContent += line + "\n"
+		} else if (inReplace) {
+			currentReplaceContent += line + "\n"
+			// Only output replacement lines immediately for in-order replacements
+			if (searchMatchIndex !== -1 && !pendingOutOfOrderReplacement) {
+				result += line + "\n"
+			}
+		}
+	}
+
+	// If this is the final chunk, we need to apply all replacements and build the final result
+	if (isFinal) {
+		// Handle the case where we're still in replace mode when processing ends
+		// and this is the final chunk - treat it as if we encountered the REPLACE marker
+		if (inReplace && searchMatchIndex !== -1) {
+			// Store this replacement
+			replacements.push({
+				start: searchMatchIndex,
+				end: searchEndIndex,
+				content: currentReplaceContent,
+			})
+
+			// If this was an in-order replacement, advance lastProcessedIndex
+			if (!pendingOutOfOrderReplacement) {
+				lastProcessedIndex = searchEndIndex
+			}
+
+			// Reset state
+			inSearch = false
+			inReplace = false
+			currentSearchContent = ""
+			currentReplaceContent = ""
+			searchMatchIndex = -1
+			searchEndIndex = -1
+			pendingOutOfOrderReplacement = false
+		}
+		// end of handling missing replace marker
+
+		// Sort replacements by start position
+		replacements.sort((a, b) => a.start - b.start)
+
+		// Rebuild the entire result by applying all replacements
+		result = ""
+		let currentPos = 0
+
+		for (const replacement of replacements) {
+			// Add original content up to this replacement
+			result += originalContent.slice(currentPos, replacement.start)
+			// Add the replacement content
+			result += replacement.content
+			// Move position to after the replaced section
+			currentPos = replacement.end
+		}
+
+		// Add any remaining original content
+		result += originalContent.slice(currentPos)
+	}
+
+	return result
+}
+
+enum ProcessingState {
+	Idle = 0,
+	StateSearch = 1 << 0,
+	StateReplace = 1 << 1,
+}
+
+class NewFileContentConstructor {
+	private originalContent: string
+	private isFinal: boolean
+	private state: number
+	private pendingNonStandardLines: string[]
+	private result: string
+	private lastProcessedIndex: number
+	private currentSearchContent: string
+	private currentReplaceContent: string
+	private searchMatchIndex: number
+	private searchEndIndex: number
+
+	constructor(originalContent: string, isFinal: boolean) {
+		this.originalContent = originalContent
+		this.isFinal = isFinal
+		this.pendingNonStandardLines = []
+		this.result = ""
+		this.lastProcessedIndex = 0
+		this.state = ProcessingState.Idle
+		this.currentSearchContent = ""
+		this.currentReplaceContent = ""
+		this.searchMatchIndex = -1
+		this.searchEndIndex = -1
+	}
+
+	private resetForNextBlock() {
+		// Reset for next block
+		this.state = ProcessingState.Idle
+		this.currentSearchContent = ""
+		this.currentReplaceContent = ""
+		this.searchMatchIndex = -1
+		this.searchEndIndex = -1
+	}
+
+	private findLastMatchingLineIndex(regx: RegExp, lineLimit: number) {
+		for (let i = lineLimit; i > 0; ) {
+			i--
+			if (this.pendingNonStandardLines[i].match(regx)) {
+				return i
+			}
+		}
+		return -1
+	}
+
+	private updateProcessingState(newState: ProcessingState) {
+		const isValidTransition =
+			(this.state === ProcessingState.Idle && newState === ProcessingState.StateSearch) ||
+			(this.state === ProcessingState.StateSearch && newState === ProcessingState.StateReplace)
+
+		if (!isValidTransition) {
+			throw new Error(
+				`Invalid state transition.\n` +
+					"Valid transitions are:\n" +
+					"- Idle → StateSearch\n" +
+					"- StateSearch → StateReplace",
+			)
+		}
+
+		this.state |= newState
+	}
+
+	private isStateActive(state: ProcessingState): boolean {
+		return (this.state & state) === state
+	}
+
+	private activateReplaceState() {
+		this.updateProcessingState(ProcessingState.StateReplace)
+	}
+
+	private activateSearchState() {
+		this.updateProcessingState(ProcessingState.StateSearch)
+		this.currentSearchContent = ""
+		this.currentReplaceContent = ""
+	}
+
+	private isSearchingActive(): boolean {
+		return this.isStateActive(ProcessingState.StateSearch)
+	}
+
+	private isReplacingActive(): boolean {
+		return this.isStateActive(ProcessingState.StateReplace)
+	}
+
+	private hasPendingNonStandardLines(pendingNonStandardLineLimit: number): boolean {
+		return this.pendingNonStandardLines.length - pendingNonStandardLineLimit < this.pendingNonStandardLines.length
+	}
+
+	public processLine(line: string) {
+		this.internalProcessLine(line, true, this.pendingNonStandardLines.length)
+	}
+
+	public getResult() {
+		// If this is the final chunk, append any remaining original content
+		if (this.isFinal && this.lastProcessedIndex < this.originalContent.length) {
+			this.result += this.originalContent.slice(this.lastProcessedIndex)
+		}
+		if (this.isFinal && this.state !== ProcessingState.Idle) {
+			throw new Error("File processing incomplete - SEARCH/REPLACE operations still active during finalization")
+		}
+		return this.result
+	}
+
+	private internalProcessLine(
+		line: string,
+		canWritependingNonStandardLines: boolean,
+		pendingNonStandardLineLimit: number,
+	): number {
+		let removeLineCount = 0
+		if (isSearchBlockStart(line)) {
+			removeLineCount = this.trimPendingNonStandardTrailingEmptyLines(pendingNonStandardLineLimit)
+			if (removeLineCount > 0) {
+				pendingNonStandardLineLimit = pendingNonStandardLineLimit - removeLineCount
+			}
+			if (this.hasPendingNonStandardLines(pendingNonStandardLineLimit)) {
+				this.tryFixSearchReplaceBlock(pendingNonStandardLineLimit)
+				canWritependingNonStandardLines && (this.pendingNonStandardLines.length = 0)
+			}
+			this.activateSearchState()
+		} else if (isSearchBlockEnd(line)) {
+			// 校验非标内容
+			if (!this.isSearchingActive()) {
+				this.tryFixSearchBlock(pendingNonStandardLineLimit)
+				canWritependingNonStandardLines && (this.pendingNonStandardLines.length = 0)
+			}
+			this.activateReplaceState()
+			this.beforeReplace()
+		} else if (isReplaceBlockEnd(line)) {
+			if (!this.isReplacingActive()) {
+				this.tryFixReplaceBlock(pendingNonStandardLineLimit)
+				canWritependingNonStandardLines && (this.pendingNonStandardLines.length = 0)
+			}
+			this.lastProcessedIndex = this.searchEndIndex
+			this.resetForNextBlock()
+		} else {
+			// Accumulate content for search or replace
+			// (currentReplaceContent is not being used for anything right now since we directly append to result.)
+			// (We artificially add a linebreak since we split on \n at the beginning. In order to not include a trailing linebreak in the final search/result blocks we need to remove it before using them. This allows for partial line matches to be correctly identified.)
+			// NOTE: search/replace blocks must be arranged in the order they appear in the file due to how we build the content using lastProcessedIndex. We also cannot strip the trailing newline since for non-partial lines it would remove the linebreak from the original content. (If we remove end linebreak from search, then we'd also have to remove it from replace but we can't know if it's a partial line or not since the model may be using the line break to indicate the end of the block rather than as part of the search content.) We require the model to output full lines in order for our fallbacks to work as well.
+			if (this.isReplacingActive()) {
+				this.currentReplaceContent += line + "\n"
+				// Output replacement lines immediately if we know the insertion point
+				if (this.searchMatchIndex !== -1) {
+					this.result += line + "\n"
+				}
+			} else if (this.isSearchingActive()) {
+				this.currentSearchContent += line + "\n"
+			} else {
+				let appendToPendingNonStandardLines = canWritependingNonStandardLines
+				if (appendToPendingNonStandardLines) {
+					// 处理非标内容
+					this.pendingNonStandardLines.push(line)
+				}
+			}
+		}
+		return removeLineCount
+	}
+
+	private beforeReplace() {
+		// Remove trailing linebreak for adding the === marker
+		// if (currentSearchContent.endsWith("\r\n")) {
+		// 	currentSearchContent = currentSearchContent.slice(0, -2)
+		// } else if (currentSearchContent.endsWith("\n")) {
+		// 	currentSearchContent = currentSearchContent.slice(0, -1)
+		// }
+
+		if (!this.currentSearchContent) {
+			// Empty search block
+			if (this.originalContent.length === 0) {
+				// New file scenario: nothing to match, just start inserting
+				this.searchMatchIndex = 0
+				this.searchEndIndex = 0
+			} else {
+				// Complete file replacement scenario: treat the entire file as matched
+				this.searchMatchIndex = 0
+				this.searchEndIndex = this.originalContent.length
+			}
+		} else {
+			// Add check for inefficient full-file search
+			// if (currentSearchContent.trim() === originalContent.trim()) {
+			// 	throw new Error(
+			// 		"The SEARCH block contains the entire file content. Please either:\n" +
+			// 			"1. Use an empty SEARCH block to replace the entire file, or\n" +
+			// 			"2. Make focused changes to specific parts of the file that need modification.",
+			// 	)
+			// }
+			// Exact search match scenario
+			const exactIndex = this.originalContent.indexOf(this.currentSearchContent, this.lastProcessedIndex)
+			if (exactIndex !== -1) {
+				this.searchMatchIndex = exactIndex
+				this.searchEndIndex = exactIndex + this.currentSearchContent.length
+			} else {
+				// Attempt fallback line-trimmed matching
+				const lineMatch = lineTrimmedFallbackMatch(
+					this.originalContent,
+					this.currentSearchContent,
+					this.lastProcessedIndex,
+				)
+				if (lineMatch) {
+					;[this.searchMatchIndex, this.searchEndIndex] = lineMatch
+				} else {
+					// Try block anchor fallback for larger blocks
+					const blockMatch = blockAnchorFallbackMatch(
+						this.originalContent,
+						this.currentSearchContent,
+						this.lastProcessedIndex,
+					)
+					if (blockMatch) {
+						;[this.searchMatchIndex, this.searchEndIndex] = blockMatch
+					} else {
+						throw new Error(
+							`The SEARCH block:\n${this.currentSearchContent.trimEnd()}\n...does not match anything in the file.`,
+						)
+					}
+				}
+			}
+		}
+		if (this.searchMatchIndex < this.lastProcessedIndex) {
+			throw new Error(
+				`The SEARCH block:\n${this.currentSearchContent.trimEnd()}\n...matched an incorrect content in the file.`,
+			)
+		}
+		// Output everything up to the match location
+		this.result += this.originalContent.slice(this.lastProcessedIndex, this.searchMatchIndex)
+	}
+
+	private tryFixSearchBlock(lineLimit: number): number {
+		let removeLineCount = 0
+		if (lineLimit < 0) {
+			lineLimit = this.pendingNonStandardLines.length
+		}
+		if (!lineLimit) {
+			throw new Error("Invalid SEARCH/REPLACE block structure - no lines available to process")
+		}
+		let searchTagRegexp = /^([-]{3,}|[<]{3,}) SEARCH$/
+		const searchTagIndex = this.findLastMatchingLineIndex(searchTagRegexp, lineLimit)
+		if (searchTagIndex !== -1) {
+			let fixLines = this.pendingNonStandardLines.slice(searchTagIndex, lineLimit)
+			fixLines[0] = SEARCH_BLOCK_START
+			for (const line of fixLines) {
+				removeLineCount += this.internalProcessLine(line, false, searchTagIndex)
+			}
+		} else {
+			throw new Error(
+				`Invalid REPLACE marker detected - could not find matching SEARCH block starting from line ${searchTagIndex + 1}`,
+			)
+		}
+		return removeLineCount
+	}
+
+	private tryFixReplaceBlock(lineLimit: number): number {
+		let removeLineCount = 0
+		if (lineLimit < 0) {
+			lineLimit = this.pendingNonStandardLines.length
+		}
+		if (!lineLimit) {
+			throw new Error()
+		}
+		let replaceBeginTagRegexp = /^[=]{3,}$/
+		const replaceBeginTagIndex = this.findLastMatchingLineIndex(replaceBeginTagRegexp, lineLimit)
+		if (replaceBeginTagIndex !== -1) {
+			// // 校验非标内容
+			// if (!this.isSearchingActive()) {
+			// 	removeLineCount += this.tryFixSearchBlock(replaceBeginTagIndex)
+			// }
+			let fixLines = this.pendingNonStandardLines.slice(replaceBeginTagIndex - removeLineCount, lineLimit - removeLineCount)
+			fixLines[0] = SEARCH_BLOCK_END
+			for (const line of fixLines) {
+				removeLineCount += this.internalProcessLine(line, false, replaceBeginTagIndex - removeLineCount)
+			}
+		} else {
+			throw new Error(`Malformed REPLACE block - missing valid separator after line ${replaceBeginTagIndex + 1}`)
+		}
+		return removeLineCount
+	}
+
+	private tryFixSearchReplaceBlock(lineLimit: number): number {
+		let removeLineCount = 0
+		if (lineLimit < 0) {
+			lineLimit = this.pendingNonStandardLines.length
+		}
+		if (!lineLimit) {
+			throw new Error()
+		}
+
+		let replaceEndTagRegexp = /^([+]{3,}|[>]{3,}) REPLACE$/
+		const replaceEndTagIndex = this.findLastMatchingLineIndex(replaceEndTagRegexp, lineLimit)
+		const likeReplaceEndTag = replaceEndTagIndex === lineLimit - 1
+		if (likeReplaceEndTag) {
+			// // 校验非标内容
+			// if (!this.isReplacingActive()) {
+			// 	removeLineCount += this.tryFixReplaceBlock(replaceEndTagIndex)
+			// }
+			let fixLines = this.pendingNonStandardLines.slice(replaceEndTagIndex - removeLineCount, lineLimit - removeLineCount)
+			fixLines[fixLines.length - 1] = REPLACE_BLOCK_END
+			for (const line of fixLines) {
+				removeLineCount += this.internalProcessLine(line, false, replaceEndTagIndex - removeLineCount)
+			}
+		} else {
+			throw new Error("Malformed SEARCH/REPLACE block structure: Missing valid closing REPLACE marker")
+		}
+		return removeLineCount
+	}
+
+	/**
+	 * Removes trailing empty lines from the pendingNonStandardLines array
+	 * @param lineLimit - The index to start checking from (exclusive).
+	 *                    Removes empty lines from lineLimit-1 backwards.
+	 * @returns The number of empty lines removed
+	 */
+	private trimPendingNonStandardTrailingEmptyLines(lineLimit: number): number {
+		let removedCount = 0
+		let i = Math.min(lineLimit, this.pendingNonStandardLines.length) - 1
+
+		while (i >= 0 && this.pendingNonStandardLines[i].trim() === "") {
+			this.pendingNonStandardLines.pop()
+			removedCount++
+			i--
+		}
+
+		return removedCount
+	}
+}
+
+export async function constructNewFileContentV2(diffContent: string, originalContent: string, isFinal: boolean): Promise<string> {
+	let newFileContentConstructor = new NewFileContentConstructor(originalContent, isFinal)
+
+	let lines = diffContent.split("\n")
+
+	// If the last line looks like a partial marker but isn't recognized,
+	// remove it because it might be incomplete.
+	const lastLine = lines[lines.length - 1]
+	if (
+		lines.length > 0 &&
+		(lastLine.startsWith(SEARCH_BLOCK_CHAR) ||
+			lastLine.startsWith(LEGACY_SEARCH_BLOCK_CHAR) ||
+			lastLine.startsWith("=") ||
+			lastLine.startsWith(REPLACE_BLOCK_CHAR) ||
+			lastLine.startsWith(LEGACY_REPLACE_BLOCK_CHAR)) &&
+		lastLine !== SEARCH_BLOCK_START &&
+		lastLine !== SEARCH_BLOCK_END &&
+		lastLine !== REPLACE_BLOCK_END
+	) {
+		lines.pop()
+	}
+
+	for (const line of lines) {
+		newFileContentConstructor.processLine(line)
+	}
+
+	let result = newFileContentConstructor.getResult()
+	return result
+}

evals/diff-edits/types.ts

@@ -33,6 +33,7 @@ export interface TestConfig {
 	diff_edit_function: string
 	thinking_tokens_budget: number
 	replay: boolean
+	diff_apply_file?: string
 }
 
 export interface SystemPromptDetails {
@@ -100,4 +101,5 @@ export interface TestInput {
 	diffEditFunction: string
 	thinkingBudgetTokens: number
 	originalDiffEditToolCallMessage?: string
+	diffApplyFile?: string
 }