readline: fix unicode line separators being ignored

PR-URL: https://github.com/nodejs/node/pull/57591
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Jordan Harband <ljharb@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/readline/interface.js

@@ -78,8 +78,15 @@ const { StringDecoder } = require('string_decoder');
 const kHistorySize = 30;
 const kMaxUndoRedoStackSize = 2048;
 const kMincrlfDelay = 100;
-// \r\n, \n, or \r followed by something other than \n
-const lineEnding = /\r?\n|\r(?!\n)/g;
+/**
+ * The end of a line is signaled by either one of the following:
+ *  - \r\n
+ *  - \n
+ *  - \r followed by something other than \n
+ *  - \u2028 (Unicode 'LINE SEPARATOR')
+ *  - \u2029 (Unicode 'PARAGRAPH SEPARATOR')
+ */
+const lineEnding = /\r?\n|\r(?!\n)|\u2028|\u2029/g;
 
 const kLineObjectStream = Symbol('line object stream');
 const kQuestionCancel = Symbol('kQuestionCancel');

test/parallel/test-readline-line-separators.js

@@ -0,0 +1,18 @@
+'use strict';
+const common = require('../common');
+const assert = require('node:assert');
+const readline = require('node:readline');
+const { Readable } = require('node:stream');
+
+const str = '012\n345\r67\r\n89\u{2028}ABC\u{2029}DEF';
+
+const rli = new readline.Interface({
+  input: Readable.from(str),
+});
+
+const linesRead = [];
+rli.on('line', (line) => linesRead.push(line));
+
+rli.on('close', common.mustCall(() => {
+  assert.deepStrictEqual(linesRead, ['012', '345', '67', '89', 'ABC', 'DEF']);
+}));