Merge pull request #360 from prathamdby/fix/edit-crlf-windows

Fix edit tool failing on Windows due to CRLF line endings

package-lock.json

@@ -4013,6 +4013,7 @@
 			"resolved": "https://registry.npmjs.org/hono/-/hono-4.11.2.tgz",
 			"integrity": "sha512-o+avdUAD1v94oHkjGBhiMhBV4WBHxhbu0+CUVH78hhphKy/OKQLxtKjkmmNcrMlbYAhAbsM/9F+l3KnYxyD3Lg==",
 			"license": "MIT",
+			"peer": true,
 			"engines": {
 				"node": ">=16.9.0"
 			}
@@ -4582,6 +4583,7 @@
 			"resolved": "https://registry.npmjs.org/lit/-/lit-3.3.2.tgz",
 			"integrity": "sha512-NF9zbsP79l4ao2SNrH3NkfmFgN/hBYSQo90saIVI1o5GpjAdCPVstVzO1MrLOakHoEhYkrtRjPK6Ob521aoYWQ==",
 			"license": "BSD-3-Clause",
+			"peer": true,
 			"dependencies": {
 				"@lit/reactive-element": "^2.1.0",
 				"lit-element": "^4.2.0",
@@ -5702,6 +5704,7 @@
 			"resolved": "https://registry.npmjs.org/tailwind-merge/-/tailwind-merge-3.4.0.tgz",
 			"integrity": "sha512-uSaO4gnW+b3Y2aWoWfFpX62vn2sR3skfhbjsEnaBI81WD1wBLlHZe5sWf0AqjksNdYTbGBEd0UasQMT3SNV15g==",
 			"license": "MIT",
+			"peer": true,
 			"funding": {
 				"type": "github",
 				"url": "https://github.com/sponsors/dcastil"
@@ -5730,7 +5733,8 @@
 			"version": "4.1.18",
 			"resolved": "https://registry.npmjs.org/tailwindcss/-/tailwindcss-4.1.18.tgz",
 			"integrity": "sha512-4+Z+0yiYyEtUVCScyfHCxOYP06L5Ne+JiHhY2IjR2KWMIWhJOYZKLSGZaP5HkZ8+bY0cxfzwDE5uOmzFXyIwxw==",
-			"license": "MIT"
+			"license": "MIT",
+			"peer": true
 		},
 		"node_modules/tapable": {
 			"version": "2.3.0",
@@ -5995,6 +5999,7 @@
 			"resolved": "https://registry.npmjs.org/vite/-/vite-7.3.0.tgz",
 			"integrity": "sha512-dZwN5L1VlUBewiP6H9s2+B3e3Jg96D0vzN+Ry73sOefebhYr9f94wwkMNN/9ouoU8pV1BqA1d1zGk8928cx0rg==",
 			"license": "MIT",
+			"peer": true,
 			"dependencies": {
 				"esbuild": "^0.27.0",
 				"fdir": "^6.5.0",

packages/coding-agent/CHANGELOG.md

@@ -6,6 +6,10 @@
 
 - **`enabledModels` setting**: Configure whitelisted models in `settings.json` (same format as `--models` CLI flag). CLI `--models` takes precedence over the setting.
 
+### Fixed
+
+- **Edit tool fails on Windows due to CRLF line endings**: Files with CRLF line endings now match correctly when LLMs send LF-only text. Line endings are normalized before matching and restored to original style on write. ([#355](https://github.com/badlogic/pi-mono/issues/355))
+
 ## [0.30.2] - 2025-12-26
 
 ### Changed

packages/coding-agent/src/core/tools/edit.ts

@@ -5,6 +5,22 @@ import { constants } from "fs";
 import { access, readFile, writeFile } from "fs/promises";
 import { resolveToCwd } from "./path-utils.js";
 
+function detectLineEnding(content: string): "\r\n" | "\n" {
+	const crlfIdx = content.indexOf("\r\n");
+	const lfIdx = content.indexOf("\n");
+	if (lfIdx === -1) return "\n";
+	if (crlfIdx === -1) return "\n";
+	return crlfIdx < lfIdx ? "\r\n" : "\n";
+}
+
+function normalizeToLF(text: string): string {
+	return text.replace(/\r\n/g, "\n").replace(/\r/g, "\n");
+}
+
+function restoreLineEndings(text: string, ending: "\r\n" | "\n"): string {
+	return ending === "\r\n" ? text.replace(/\n/g, "\r\n") : text;
+}
+
 /**
  * Generate a unified diff string with line numbers and context
  */
@@ -169,8 +185,13 @@ export function createEditTool(cwd: string): AgentTool<typeof editSchema> {
 							return;
 						}
 
+						const originalEnding = detectLineEnding(content);
+						const normalizedContent = normalizeToLF(content);
+						const normalizedOldText = normalizeToLF(oldText);
+						const normalizedNewText = normalizeToLF(newText);
+
 						// Check if old text exists
-						if (!content.includes(oldText)) {
+						if (!normalizedContent.includes(normalizedOldText)) {
 							if (signal) {
 								signal.removeEventListener("abort", onAbort);
 							}
@@ -183,7 +204,7 @@ export function createEditTool(cwd: string): AgentTool<typeof editSchema> {
 						}
 
 						// Count occurrences
-						const occurrences = content.split(oldText).length - 1;
+						const occurrences = normalizedContent.split(normalizedOldText).length - 1;
 
 						if (occurrences > 1) {
 							if (signal) {
@@ -204,11 +225,14 @@ export function createEditTool(cwd: string): AgentTool<typeof editSchema> {
 
 						// Perform replacement using indexOf + substring (raw string replace, no special character interpretation)
 						// String.replace() interprets $ in the replacement string, so we do manual replacement
-						const index = content.indexOf(oldText);
+						const index = normalizedContent.indexOf(normalizedOldText);
-						const newContent = content.substring(0, index) + newText + content.substring(index + oldText.length);
+						const normalizedNewContent =
+							normalizedContent.substring(0, index) +
+							normalizedNewText +
+							normalizedContent.substring(index + normalizedOldText.length);
 
 						// Verify the replacement actually changed something
-						if (content === newContent) {
+						if (normalizedContent === normalizedNewContent) {
 							if (signal) {
 								signal.removeEventListener("abort", onAbort);
 							}
@@ -220,7 +244,8 @@ export function createEditTool(cwd: string): AgentTool<typeof editSchema> {
 							return;
 						}
 
-						await writeFile(absolutePath, newContent, "utf-8");
+						const finalContent = restoreLineEndings(normalizedNewContent, originalEnding);
+						await writeFile(absolutePath, finalContent, "utf-8");
 
 						// Check if aborted after writing
 						if (aborted) {
@@ -236,10 +261,10 @@ export function createEditTool(cwd: string): AgentTool<typeof editSchema> {
 							content: [
 								{
 									type: "text",
-									text: `Successfully replaced text in ${path}. Changed ${oldText.length} characters to ${newText.length} characters.`,
+									text: `Successfully replaced text in ${path}.`,
 								},
 							],
-							details: { diff: generateDiffString(content, newContent) },
+							details: { diff: generateDiffString(normalizedContent, normalizedNewContent) },
 						});
 					} catch (error: any) {
 						// Clean up abort handler

packages/coding-agent/test/tools.test.ts

@@ -1,4 +1,4 @@
-import { mkdirSync, rmSync, writeFileSync } from "fs";
+import { mkdirSync, readFileSync, rmSync, writeFileSync } from "fs";
 import { tmpdir } from "os";
 import { join } from "path";
 import { afterEach, beforeEach, describe, expect, it } from "vitest";
@@ -365,3 +365,72 @@ describe("Coding Agent Tools", () => {
 		});
 	});
 });
+
+describe("edit tool CRLF handling", () => {
+	let testDir: string;
+
+	beforeEach(() => {
+		testDir = join(tmpdir(), `coding-agent-crlf-test-${Date.now()}`);
+		mkdirSync(testDir, { recursive: true });
+	});
+
+	afterEach(() => {
+		rmSync(testDir, { recursive: true, force: true });
+	});
+
+	it("should match LF oldText against CRLF file content", async () => {
+		const testFile = join(testDir, "crlf-test.txt");
+
+		writeFileSync(testFile, "line one\r\nline two\r\nline three\r\n");
+
+		const result = await editTool.execute("test-crlf-1", {
+			path: testFile,
+			oldText: "line two\n",
+			newText: "replaced line\n",
+		});
+
+		expect(getTextOutput(result)).toContain("Successfully replaced");
+	});
+
+	it("should preserve CRLF line endings after edit", async () => {
+		const testFile = join(testDir, "crlf-preserve.txt");
+		writeFileSync(testFile, "first\r\nsecond\r\nthird\r\n");
+
+		await editTool.execute("test-crlf-2", {
+			path: testFile,
+			oldText: "second\n",
+			newText: "REPLACED\n",
+		});
+
+		const content = readFileSync(testFile, "utf-8");
+		expect(content).toBe("first\r\nREPLACED\r\nthird\r\n");
+	});
+
+	it("should preserve LF line endings for LF files", async () => {
+		const testFile = join(testDir, "lf-preserve.txt");
+		writeFileSync(testFile, "first\nsecond\nthird\n");
+
+		await editTool.execute("test-lf-1", {
+			path: testFile,
+			oldText: "second\n",
+			newText: "REPLACED\n",
+		});
+
+		const content = readFileSync(testFile, "utf-8");
+		expect(content).toBe("first\nREPLACED\nthird\n");
+	});
+
+	it("should detect duplicates across CRLF/LF variants", async () => {
+		const testFile = join(testDir, "mixed-endings.txt");
+
+		writeFileSync(testFile, "hello\r\nworld\r\n---\r\nhello\nworld\n");
+
+		await expect(
+			editTool.execute("test-crlf-dup", {
+				path: testFile,
+				oldText: "hello\nworld\n",
+				newText: "replaced\n",
+			}),
+		).rejects.toThrow(/Found 2 occurrences/);
+	});
+});