From b9f64536c8bf8097a8993d1480ec5a03b254fab0 Mon Sep 17 00:00:00 2001
From: Prince J Wesley <princejohnwesley@gmail.com>
Date: Wed, 21 Feb 2018 17:48:23 +0530
Subject: [PATCH] repl: better handling of recoverable errors

Below syntax errors are handled without force .break/clear
  - Unexpected Token (prefix errors)
  - missing ) after argument list

In the multiline expression, recoverable errors are truly
recoverable, otherwise syntax error will be thrown.
---
 lib/repl.js                | 11 +++---
 test/parallel/test-repl.js | 74 +++++++++++++++++++++++++++++++++++---
 2 files changed, 75 insertions(+), 10 deletions(-)

diff --git a/lib/repl.js b/lib/repl.js
index 8201630c3a6389..1d51069acdcb63 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -1454,14 +1454,15 @@ function isRecoverableError(e, code) {
   if (e && e.name === 'SyntaxError') {
     var message = e.message;
     if (message === 'Unterminated template literal' ||
-        message === 'Missing } in template expression') {
+        message === 'Unexpected end of input') {
       return true;
     }
 
-    if (message.startsWith('Unexpected end of input') ||
-        message.startsWith('missing ) after argument list') ||
-        message.startsWith('Unexpected token'))
-      return true;
+    if (message === 'missing ) after argument list') {
+      const frames = e.stack.split(/\r?\n/);
+      const pos = frames.findIndex((f) => f.match(/^\s*\^+$/));
+      return pos > 0 && frames[pos - 1].length === frames[pos].length;
+    }
 
     if (message === 'Invalid or unexpected token')
       return isCodeRecoverable(code);
diff --git a/test/parallel/test-repl.js b/test/parallel/test-repl.js
index cb167372ef52fd..e14398541dd8de 100644
--- a/test/parallel/test-repl.js
+++ b/test/parallel/test-repl.js
@@ -163,13 +163,23 @@ const errorTests = [
     send: '.break',
     expect: ''
   },
-  // Template expressions can cross lines
+  // Template expressions
   {
     send: '`io.js ${"1.0"',
+    expect: [
+      kSource,
+      kArrow,
+      '',
+      /^SyntaxError: /,
+      ''
+    ]
+  },
+  {
+    send: '`io.js ${',
     expect: '... '
   },
   {
-    send: '+ ".2"}`',
+    send: '"1.0" + ".2"}`',
     expect: '\'io.js 1.0.2\''
   },
   // Dot prefix in multiline commands aren't treated as commands
@@ -644,14 +654,68 @@ const errorTests = [
   },
   // Do not parse `...[]` as a REPL keyword
   {
-    send: '...[]\n',
-    expect: '... ... '
+    send: '...[]',
+    expect: [
+      kSource,
+      kArrow,
+      '',
+      /^SyntaxError: /,
+      ''
+    ]
   },
   // bring back the repl to prompt
   {
     send: '.break',
     expect: ''
-  }
+  },
+  {
+    send: 'console.log("Missing comma in arg list" process.version)',
+    expect: [
+      kSource,
+      kArrow,
+      '',
+      /^SyntaxError: /,
+      ''
+    ]
+  },
+  {
+    send: 'x = {\nfield\n{',
+    expect: [
+      '... ... {',
+      kArrow,
+      '',
+      /^SyntaxError: /,
+      ''
+    ]
+  },
+  {
+    send: '(2 + 3))',
+    expect: [
+      kSource,
+      kArrow,
+      '',
+      /^SyntaxError: /,
+      ''
+    ]
+  },
+  {
+    send: 'if (typeof process === "object"); {',
+    expect: '... '
+  },
+  {
+    send: 'console.log("process is defined");',
+    expect: '... '
+  },
+  {
+    send: '} else {',
+    expect: [
+      kSource,
+      kArrow,
+      '',
+      /^SyntaxError: /,
+      ''
+    ]
+  },
 ];
 
 const tcpTests = [