repl: fix /dev/null history file regression

This fixes a regression from 83887f3 where ftruncate() fails on
a file symlinked to /dev/null.

PR-URL: #12762
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: mscdex

lib/internal/repl.js

@@ -173,25 +173,18 @@ function setupHistory(repl, historyPath, oldHistoryPath, ready) {
       return ready(err);
     }
     fs.ftruncate(hnd, 0, (err) => {
-      return onftruncate(err, hnd);
+      repl._historyHandle = hnd;
+      repl.on('line', online);
+
+      // reading the file data out erases it
+      repl.once('flushHistory', function() {
+        repl.resume();
+        ready(null, repl);
+      });
+      flushHistory();
     });
   }
 
-  function onftruncate(err, hnd) {
-    if (err) {
-      return ready(err);
-    }
-    repl._historyHandle = hnd;
-    repl.on('line', online);
-
-    // reading the file data out erases it
-    repl.once('flushHistory', function() {
-      repl.resume();
-      ready(null, repl);
-    });
-    flushHistory();
-  }
-
   // ------ history listeners ------
   function online() {
     repl._flushing = true;

test/parallel/test-repl-persistent-history.js

@@ -78,6 +78,8 @@ const emptyHistoryPath = path.join(fixtures, '.empty-repl-history-file');
 const defaultHistoryPath = path.join(common.tmpDir, '.node_repl_history');
 const emptyHiddenHistoryPath = path.join(fixtures,
                                          '.empty-hidden-repl-history-file');
+const devNullHistoryPath = path.join(common.tmpDir,
+                                     '.dev-null-repl-history-file');
 
 const tests = [
   {
@@ -178,6 +180,15 @@ const tests = [
     test: [UP],
     expected: [prompt]
   },
+  {
+    before: function before() {
+      if (!common.isWindows)
+        fs.symlinkSync('/dev/null', devNullHistoryPath);
+    },
+    env: { NODE_REPL_HISTORY: devNullHistoryPath },
+    test: [UP],
+    expected: [prompt]
+  },
   { // Make sure this is always the last test, since we change os.homedir()
     before: function before() {
       // Mock os.homedir() failure