repl: fix for a+ fd clearing the file on read

The second step of augmenting the internal REPL with persistent
history was to re-open the history file with a 'w' handle. This
truncated the file. If a user did not enter a new line before
closing the REPL, their history would be deleted.

PR-URL: #1605
Reviewed-By: Roman Reiss <me@silverwind.io>

lib/internal/repl.js

@@ -107,8 +107,13 @@ function setupHistory(repl, historyPath, ready) {
     }
     repl._historyHandle = hnd;
     repl.on('line', online);
-    repl.resume();
-    return ready(null, repl);
+
+    // reading the file data out erases it
+    repl.once('flushHistory', function() {
+      repl.resume();
+      ready(null, repl);
+    });
+    flushHistory();
   }
 
   // ------ history listeners ------

src/node.js

@@ -130,7 +130,8 @@
         // If -i or --interactive were passed, or stdin is a TTY.
         if (process._forceRepl || NativeModule.require('tty').isatty(0)) {
           // REPL
-          Module.requireRepl().createInternalRepl(process.env, function(err, repl) {
+          var cliRepl = Module.requireRepl();
+          cliRepl.createInternalRepl(process.env, function(err, repl) {
             if (err) {
               throw err;
             }