From 2c84c946bed09391b6006c12f3bfc84b532b339b Mon Sep 17 00:00:00 2001
From: Alex Kocharin <alex@kocharin.ru>
Date: Sun, 5 Jul 2015 19:16:47 +0300
Subject: [PATCH] readline: fix freeze if `keypress` event throws

`emitKeys` is a generator which emits `keypress` events in an infinite
loop. But if `keypress` event handler throws, the error stops the loop,
leaving generator in a broken state. So this patch restarts the generator
when an error occures.
---
 lib/readline.js                          | 10 +++++++++-
 test/parallel/test-readline-interface.js | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/lib/readline.js b/lib/readline.js
index d186eef94ae328..741f58b934b688 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -910,7 +910,15 @@ function emitKeypressEvents(stream) {
       var r = stream[KEYPRESS_DECODER].write(b);
       if (r) {
         for (var i = 0; i < r.length; i++) {
-          stream[ESCAPE_DECODER].next(r[i]);
+          try {
+            stream[ESCAPE_DECODER].next(r[i]);
+          } catch (err) {
+            // if the generator throws (it could happen in the `keypress`
+            // event), we need to restart it.
+            stream[ESCAPE_DECODER] = emitKeys(stream);
+            stream[ESCAPE_DECODER].next();
+            throw err;
+          }
         }
       }
     } else {
diff --git a/test/parallel/test-readline-interface.js b/test/parallel/test-readline-interface.js
index 6ee9ad227896b1..e11cfd333b9dfb 100644
--- a/test/parallel/test-readline-interface.js
+++ b/test/parallel/test-readline-interface.js
@@ -192,6 +192,24 @@ function isWarned(emitter) {
   assert.equal(callCount, 1);
   rli.close();
 
+  // Regression test for repl freeze, #1968:
+  // check that nothing fails if 'keypress' event throws.
+  fi = new FakeInput();
+  rli = new readline.Interface({ input: fi, output: fi, terminal: true });
+  var keys = [];
+  fi.on('keypress', function(key) {
+    keys.push(key);
+    if (key === 'X') {
+      throw new Error('bad thing happened');
+    }
+  });
+  try {
+    fi.emit('data', 'fooX');
+  } catch(e) { }
+  fi.emit('data', 'bar');
+  assert.equal(keys.join(''), 'fooXbar');
+  rli.close();
+
   // calling readline without `new`
   fi = new FakeInput();
   rli = readline.Interface({ input: fi, output: fi, terminal: terminal });