From e8c91e7557fd2dd0a874e14da8f6908e141e4dcd Mon Sep 17 00:00:00 2001
From: Rich Trott <rtrott@gmail.com>
Date: Wed, 1 Jun 2016 23:13:45 -0700
Subject: [PATCH] repl: refine handling of illegal tokens

Illegal tokens are only recoverable in string literals, RegExp literals,
and block comments. If not in one of these constructs, immediately
return an error rather than giving the user false hope by giving them a
chance to try to recover.

PR-URL: https://github.com/nodejs/node/pull/7104
Fixes: https://github.com/nodejs/node/issues/3611
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
---
 lib/repl.js                | 18 +++++++++++++++---
 test/parallel/test-repl.js |  4 ++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/repl.js b/lib/repl.js
index b58cf499cda226..387e3b5446f678 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -1154,6 +1154,11 @@ REPLServer.prototype.convertToContext = function(cmd) {
   return cmd;
 };
 
+function bailOnIllegalToken(parser) {
+  return parser._literal === null &&
+         !parser.blockComment &&
+         !parser.regExpLiteral;
+}
 
 // If the error is that we've unexpectedly ended the input,
 // then let the user try to recover by adding more input.
@@ -1166,9 +1171,16 @@ function isRecoverableError(e, self) {
       return true;
     }
 
-    return message.startsWith('Unexpected end of input') ||
-      message.startsWith('Unexpected token') ||
-      message.startsWith('missing ) after argument list');
+    if (message.startsWith('Unexpected end of input') ||
+        message.startsWith('missing ) after argument list'))
+      return true;
+
+    if (message.startsWith('Unexpected token')) {
+      if (message.includes('ILLEGAL') && bailOnIllegalToken(self.lineParser))
+        return false;
+      else
+        return true;
+    }
   }
   return false;
 }
diff --git a/test/parallel/test-repl.js b/test/parallel/test-repl.js
index 2ec996897a1cae..fe4bcd32deda12 100644
--- a/test/parallel/test-repl.js
+++ b/test/parallel/test-repl.js
@@ -324,6 +324,10 @@ function error_test() {
             'undefined\n' + prompt_unix },
     { client: client_unix, send: '{ var x = 4; }',
       expect: 'undefined\n' + prompt_unix },
+    // Illegal token is not recoverable outside string literal, RegExp literal,
+    // or block comment. https://github.com/nodejs/node/issues/3611
+    { client: client_unix, send: 'a = 3.5e',
+      expect: /^SyntaxError: Unexpected token ILLEGAL/ },
   ]);
 }