repl: make sure historyPath is trimmed

If one were to set NODE_REPL_HISTORY to a string that contains only a
space (" "), then the history file would be created with that name
which can cause problems are certain systems.

PR-URL: https://github.com/nodejs/node/pull/4539
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>

1 files changed, 12 insertions, 1 deletions

diff --git a/lib/internal/repl.js b/lib/internal/repl.js
index e6b41fbdd8..371446a83b 100644
--- a/lib/internal/repl.js
+++ b/lib/internal/repl.js
@@ -55,15 +55,26 @@ function createRepl(env, opts, cb) {
   }
 
   const repl = REPL.start(opts);
-  if (opts.terminal && env.NODE_REPL_HISTORY !== '') {
+  if (opts.terminal) {
     return setupHistory(repl, env.NODE_REPL_HISTORY,
                         env.NODE_REPL_HISTORY_FILE, cb);
   }
+
   repl._historyPrev = _replHistoryMessage;
   cb(null, repl);
 }
 
 function setupHistory(repl, historyPath, oldHistoryPath, ready) {
+  // Empty string disables persistent history.
+
+  if (typeof historyPath === 'string')
+    historyPath = historyPath.trim();
+
+  if (historyPath === '') {
+    repl._historyPrev = _replHistoryMessage;
+    return ready(null, repl);
+  }
+
   if (!historyPath) {
     try {
       historyPath = path.join(os.homedir(), '.node_repl_history');