repl: fix dedup comparing normalized line against raw history

lib/internal/repl/history.js

@@ -142,7 +142,7 @@ class ReplHistory {
     if (this[kHistory].length === 0 || this[kHistory][0] !== normalizedLine) {
       if (this[kRemoveHistoryDuplicates]) {
         // Remove older history line if identical to new one
-        const dupIndex = ArrayPrototypeIndexOf(this[kHistory], line);
+        const dupIndex = ArrayPrototypeIndexOf(this[kHistory], normalizedLine);
         if (dupIndex !== -1) ArrayPrototypeSplice(this[kHistory], dupIndex, 1);
       }
 

test/parallel/test-repl-history-dedup-multiline.js

@@ -0,0 +1,44 @@
+'use strict';
+
+const common = require('../common');
+
+if (process.env.TERM === 'dumb') {
+  common.skip('skipping - dumb terminal');
+}
+
+const assert = require('assert');
+const readline = require('readline');
+const { EventEmitter } = require('events');
+
+class FakeInput extends EventEmitter {
+  resume() {}
+  pause() {}
+  write() {}
+  end() {}
+}
+FakeInput.prototype.readable = true;
+
+{
+  const fi = new FakeInput();
+  const rli = new readline.Interface({
+    input: fi,
+    output: fi,
+    terminal: true,
+    removeHistoryDuplicates: true,
+  });
+
+  function submitLine(line) {
+    rli.line = line;
+    fi.emit('keypress', '', { name: 'enter' });
+  }
+
+  submitLine('line1\nline2');
+  submitLine('other');
+  submitLine('line1\nline2');
+
+  assert.strictEqual(rli.history.length, 2);
+  assert.strictEqual(rli.history[0], 'line2\rline1');
+  assert.strictEqual(rli.history[1], 'other');
+
+  rli.close();
+}