fix #213 tmp.file must not unlink file when discarding the file descr…

…iptor, similar to tmp.fileSync

lib/tmp.js

@@ -253,29 +253,14 @@ function file(options, callback) {
       /* istanbul ignore else */
       if (err) return cb(err);
 
-      // FIXME overall handling of opts.discardDescriptor is off
       if (opts.discardDescriptor) {
-        // FIXME? must not unlink as the user expects the filename to be reserved
-        return fs.close(fd, function _discardCallback(err) {
-          /* istanbul ignore else */
-          if (err) {
-            // Low probability, and the file exists, so this could be
-            // ignored.  If it isn't we certainly need to unlink the
-            // file, and if that fails too its error is more
-            // important.
-            try {
-              fs.unlinkSync(name);
-            } catch (e) {
-              if (!isENOENT(e)) {
-                err = e;
-              }
-            }
-            return cb(err);
-          }
-          cb(null, name, undefined, _prepareTmpFileRemoveCallback(name, -1, opts));
+        return fs.close(fd, function _discardCallback(possibleErr) {
+          // the chance of getting an error on close here is rather low and might occur in the most edgiest cases only
+          return cb(possibleErr, name, undefined, _prepareTmpFileRemoveCallback(name, -1, opts, false));
         });
       } else {
-        // FIXME detachDescriptor passes the descriptor whereas discardDescriptor closes it
+        // detachDescriptor passes the descriptor whereas discardDescriptor closes it, either way, we no longer care
+        // about the descriptor
         const discardOrDetachDescriptor = opts.discardDescriptor || opts.detachDescriptor;
         cb(null, name, fd, _prepareTmpFileRemoveCallback(name, discardOrDetachDescriptor ? -1 : fd, opts, false));
       }