fix: bare newline handling repaints (antigravity)

src/tests/utils/stdioProxy.test.ts

@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
-import { disableWin32InputMode, enableWin32InputMode } from "../../utils/ansi.js";
+import { disableWin32InputMode, enableWin32InputMode, index } from "../../utils/ansi.js";
 import { StdioProxy } from "../../ui/stdioProxy.js";
 
 const createRouter = () => {
@@ -74,3 +74,61 @@ test("keeps unrelated outbound CSI sequences", () => {
   expect(proxy.handleOutput("\u001B[?25loutput")).toBe("\u001B[?25loutput");
   expect(toggles).toEqual([]);
 });
+
+test.each([
+  ["kitty keyboard query", "\u001B[?u"],
+  ["kitty keyboard set", "\u001B[=1;1u"],
+  ["kitty keyboard reset", "\u001B[=0;1u"],
+  ["kitty keyboard push", "\u001B[>1u"],
+  ["kitty keyboard pop", "\u001B[<1u"],
+  ["modify other keys", "\u001B[>4;2m"],
+  ["modify other keys reset", "\u001B[>4m"],
+])("strips outbound %s", (_name, sequence) => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput(`before${sequence}after`)).toBe("beforeafter");
+});
+
+test("handles outbound keyboard protocol upgrades split across chunks", () => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput("before\u001B[>4;")).toBe("before");
+  expect(proxy.handleOutput("2mafter")).toBe("after");
+});
+
+test.each([
+  ["restore cursor", "\u001B[u"],
+  ["secondary device attributes", "\u001B[>c"],
+  ["bracketed paste", "\u001B[?2004h"],
+  ["alternate buffer", "\u001B[?1049h"],
+  ["truecolor", "\u001B[38;2;219;177;49m"],
+])("keeps outbound %s", (_name, sequence) => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput(sequence)).toBe(sequence);
+});
+
+test("rewrites bare line feeds so the column survives newline auto-return", () => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput("\u001B[H\u001B[2J\n\u001B[5C▄▀▀▄\n\u001B[5D▀▀▀▀▀▀")).toBe(`\u001B[H\u001B[2J${index}\u001B[5C▄▀▀▄${index}\u001B[5D▀▀▀▀▀▀`);
+});
+
+test("keeps carriage return line feed pairs intact", () => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput("first\r\nsecond\r\n")).toBe("first\r\nsecond\r\n");
+});
+
+test("rewrites consecutive bare line feeds", () => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput("\r\n\n\n line")).toBe(`\r\n${index}${index} line`);
+});
+
+test("rewrites a line feed split from its carriage return, which lands in the same column", () => {
+  const { proxy } = createRouter();
+
+  expect(proxy.handleOutput("first\r")).toBe("first\r");
+  expect(proxy.handleOutput("\nsecond")).toBe(`${index}second`);
+});

src/ui/stdioProxy.ts

@@ -5,22 +5,41 @@ import readline from "node:readline";
 import { PassThrough } from "node:stream";
 import { StringDecoder } from "node:string_decoder";
 
-import { disableWin32InputMode, enableWin32InputMode } from "../utils/ansi.js";
+import * as ansi from "../utils/ansi.js";
 import type { KeyPressEvent } from "./suggestionManager.js";
 
 // eslint-disable-next-line no-control-regex
 const cursorPositionReport = new RegExp("\\u001B\\[\\??\\d+;\\d+R", "g");
 // eslint-disable-next-line no-control-regex
 const partialCursorPositionReport = new RegExp("\\u001B\\[\\??\\d*(?:;\\d*)?$");
+// blocks win32 input mode, the kitty keyboard protocol and xterm modifyOtherKeys from upgrading input & breaking node's readline
 // eslint-disable-next-line no-control-regex
-const win32InputMode = new RegExp("\\u001B\\[\\?9001([hl])", "g");
-const win32InputModeSequences = [enableWin32InputMode, disableWin32InputMode];
+const keyEncodingUpgrade = new RegExp("\\u001B\\[(?:\\?9001([hl])|\\?u|[=><][\\d;]*u|>[\\d;]*m)", "g");
+// a trailing portion of a key encoding upgrade
+// eslint-disable-next-line no-control-regex
+const partialKeyEncodingUpgrade = new RegExp("^\\u001B(?:\\[(?:\\?(?:9(?:0(?:0(?:1)?)?)?)?|[=><][\\d;]*)?)?$");
+const carriageReturn = "\r".charCodeAt(0);
 
-const getPartialWin32InputMode = (input: string): string => {
+const getPartialKeyEncodingUpgrade = (input: string): string => {
   const sequenceStart = input.lastIndexOf("\u001B");
   if (sequenceStart === -1) return "";
   const suffix = input.slice(sequenceStart);
-  return win32InputModeSequences.some((sequence) => sequence !== suffix && sequence.startsWith(suffix)) ? suffix : "";
+  return partialKeyEncodingUpgrade.test(suffix) ? suffix : "";
+};
+
+const replaceBareLineFeeds = (output: string): string => {
+  let feed = output.indexOf("\n");
+  if (feed === -1) return output;
+
+  let replaced = "";
+  let copiedTo = 0;
+  for (; feed !== -1; feed = output.indexOf("\n", feed + 1)) {
+    if (output.charCodeAt(feed - 1) === carriageReturn) continue;
+    replaced += output.slice(copiedTo, feed);
+    replaced += ansi.index;
+    copiedTo = feed + 1;
+  }
+  return replaced + output.slice(copiedTo);
 };
 
 type StdioProxyOptions = {
@@ -54,13 +73,15 @@ export class StdioProxy {
 
   handleOutput(data: string): string {
     const input = this.#pendingOutput + data;
-    this.#pendingOutput = getPartialWin32InputMode(input);
+    this.#pendingOutput = getPartialKeyEncodingUpgrade(input);
     const completeInput = this.#pendingOutput.length === 0 ? input : input.slice(0, -this.#pendingOutput.length);
 
-    return completeInput.replace(win32InputMode, (_sequence, mode: string) => {
-      this.#onWin32InputMode(mode === "h");
-      return "";
-    });
+    return replaceBareLineFeeds(
+      completeInput.replace(keyEncodingUpgrade, (_sequence, win32Mode?: string) => {
+        if (win32Mode != null) this.#onWin32InputMode(win32Mode === "h");
+        return "";
+      }),
+    );
   }
 
   dispose(): string {

src/utils/ansi.ts

@@ -29,6 +29,7 @@ export const resetLine = CSI + "2K";
 export const enableWin32InputMode = CSI + "?9001h";
 export const disableWin32InputMode = CSI + "?9001l";
 export const resetToInitialState = ESC + "c"; // RIS - Reset to Initial State
+export const index = ESC + "D"; // IND - move down a row keeping the column (avoids newline auto-return, windows terminal default)
 export const cursorBackward = (count = 1) => CSI + count + "D";
 export const cursorForward = (count = 1) => CSI + count + "C";
 export const cursorTo = ({ x, y }: { x?: number; y?: number }) => {