fix(tui): remove backslash input buffering (#1037)

Instead of buffering `\` and waiting for the next key, let it be
inserted immediately. On Enter, check if preceded by `\` and treat as
newline.

Removed backslash handling from the Input component entirely.

packages/tui/src/components/editor.ts

@@ -184,7 +184,6 @@ export class Editor implements Component, Focusable {
 	// Bracketed paste mode buffering
 	private pasteBuffer: string = "";
 	private isInPaste: boolean = false;
-	private pendingShiftEnter: boolean = false;
 
 	// Prompt history for up/down navigation
 	private history: string[] = [];
@@ -448,21 +447,6 @@ export class Editor implements Component, Focusable {
 			return;
 		}
 
-		if (this.pendingShiftEnter) {
-			if (data === "\r") {
-				this.pendingShiftEnter = false;
-				this.addNewLine();
-				return;
-			}
-			this.pendingShiftEnter = false;
-			this.insertCharacter("\\");
-		}
-
-		if (data === "\\") {
-			this.pendingShiftEnter = true;
-			return;
-		}
-
 		// Ctrl+C - let parent handle (exit/clear)
 		if (kb.matches(data, "copy")) {
 			return;
@@ -602,8 +586,7 @@ export class Editor implements Component, Focusable {
 			data === "\x1b\r" ||
 			data === "\x1b[13;2~" ||
 			(data.length > 1 && data.includes("\x1b") && data.includes("\r")) ||
-			(data === "\n" && data.length === 1) ||
-			data === "\\\r"
+			(data === "\n" && data.length === 1)
 		) {
 			this.addNewLine();
 			return;
@@ -613,6 +596,15 @@ export class Editor implements Component, Focusable {
 		if (kb.matches(data, "submit")) {
 			if (this.disableSubmit) return;
 
+			// Workaround for terminals without Shift+Enter support:
+			// If char before cursor is \, delete it and insert newline instead of submitting.
+			const currentLine = this.state.lines[this.state.cursorLine] || "";
+			if (this.state.cursorCol > 0 && currentLine[this.state.cursorCol - 1] === "\\") {
+				this.handleBackspace();
+				this.addNewLine();
+				return;
+			}
+
 			let result = this.state.lines.join("\n").trim();
 			for (const [pasteId, pasteContent] of this.pastes) {
 				const markerRegex = new RegExp(`\\[paste #${pasteId}( (\\+\\d+ lines|\\d+ chars))?\\]`, "g");

packages/tui/src/components/input.ts

@@ -19,7 +19,6 @@ export class Input implements Component, Focusable {
 	// Bracketed paste mode buffering
 	private pasteBuffer: string = "";
 	private isInPaste: boolean = false;
-	private pendingShiftEnter: boolean = false;
 
 	getValue(): string {
 		return this.value;
@@ -68,22 +67,6 @@ export class Input implements Component, Focusable {
 			return;
 		}
 
-		if (this.pendingShiftEnter) {
-			if (data === "\r") {
-				this.pendingShiftEnter = false;
-				if (this.onSubmit) this.onSubmit(this.value);
-				return;
-			}
-			this.pendingShiftEnter = false;
-			this.value = `${this.value.slice(0, this.cursor)}\\${this.value.slice(this.cursor)}`;
-			this.cursor += 1;
-		}
-
-		if (data === "\\") {
-			this.pendingShiftEnter = true;
-			return;
-		}
-
 		const kb = getEditorKeybindings();
 
 		// Escape/Cancel

packages/tui/test/editor.test.ts

@@ -283,8 +283,17 @@ describe("Editor component", () => {
 		});
 	});
 
-	describe("Shift+Enter handling", () => {
-		it("treats split VS Code Shift+Enter as a newline", () => {
+	describe("Backslash+Enter newline workaround", () => {
+		it("inserts backslash immediately (no buffering)", () => {
+			const editor = new Editor(createTestTUI(), defaultEditorTheme);
+
+			editor.handleInput("\\");
+
+			// Backslash should be visible immediately, not buffered
+			assert.strictEqual(editor.getText(), "\\");
+		});
+
+		it("converts standalone backslash to newline on Enter", () => {
 			const editor = new Editor(createTestTUI(), defaultEditorTheme);
 
 			editor.handleInput("\\");
@@ -293,7 +302,7 @@ describe("Editor component", () => {
 			assert.strictEqual(editor.getText(), "\n");
 		});
 
-		it("inserts a literal backslash when not followed by Enter", () => {
+		it("inserts backslash normally when followed by other characters", () => {
 			const editor = new Editor(createTestTUI(), defaultEditorTheme);
 
 			editor.handleInput("\\");
@@ -301,6 +310,35 @@ describe("Editor component", () => {
 
 			assert.strictEqual(editor.getText(), "\\x");
 		});
+
+		it("does not trigger newline when backslash is not immediately before cursor", () => {
+			const editor = new Editor(createTestTUI(), defaultEditorTheme);
+			let submitted = false;
+
+			editor.onSubmit = () => {
+				submitted = true;
+			};
+
+			editor.handleInput("\\");
+			editor.handleInput("x");
+			editor.handleInput("\r");
+
+			// Should submit, not insert newline (backslash not at cursor)
+			assert.strictEqual(submitted, true);
+		});
+
+		it("only removes one backslash when multiple are present", () => {
+			const editor = new Editor(createTestTUI(), defaultEditorTheme);
+
+			editor.handleInput("\\");
+			editor.handleInput("\\");
+			editor.handleInput("\\");
+			assert.strictEqual(editor.getText(), "\\\\\\");
+
+			editor.handleInput("\r");
+			// Only the last backslash is removed, newline inserted
+			assert.strictEqual(editor.getText(), "\\\\\n");
+		});
 	});
 
 	describe("Unicode text editing behavior", () => {

packages/tui/test/input.test.ts

@@ -3,23 +3,28 @@ import { describe, it } from "node:test";
 import { Input } from "../src/components/input.js";
 
 describe("Input component", () => {
-	it("treats split VS Code Shift+Enter as submit", () => {
+	it("submits value including backslash on Enter", () => {
 		const input = new Input();
 		let submitted: string | undefined;
 
-		input.setValue("hello");
 		input.onSubmit = (value) => {
 			submitted = value;
 		};
 
+		// Type hello, then backslash, then Enter
+		input.handleInput("h");
+		input.handleInput("e");
+		input.handleInput("l");
+		input.handleInput("l");
+		input.handleInput("o");
 		input.handleInput("\\");
 		input.handleInput("\r");
 
-		assert.strictEqual(submitted, "hello");
-		assert.strictEqual(input.getValue(), "hello");
+		// Input is single-line, no backslash+Enter workaround
+		assert.strictEqual(submitted, "hello\\");
 	});
 
-	it("inserts a literal backslash when not followed by Enter", () => {
+	it("inserts backslash as regular character", () => {
 		const input = new Input();
 
 		input.handleInput("\\");