Undefined index: menu in menu_target_edit_form_extra_elements()

+++ b/menu_target.admin.inc
@@ -35,7 +35,15 @@ function menu_target_edit_form_extra_elements(&$form, $node_form) {
+      elseif(!empty($form['options']['#value'])) {

this has a different logic than before. previously it was used if !$node_form

+++ b/menu_target.admin.inc
@@ -35,7 +35,15 @@ function menu_target_edit_form_extra_elements(&$form, $node_form) {
+    elseif(!empty($form['options']['#value'])) {

missing space after if

and finally...!

I think there's a better solution. Now the checkbox 'Open in a new window' appears on a node form even if no menus are selected. This is because $enabled_menus is never empty:

<?php
function menu_target_edit_form_extra_elements(&$form, $node_form) {

  if ($node_form) {
    $type = $form['#node']->type;
    $enabled_menus = variable_get('menu_options_' . $type, array('main-menu' => 'main-menu'));
    if (empty($enabled_menus)) {
      return;
    }

?>

This is also causing the aforementioned notice. Instead I propose the following:

<?php
function menu_target_edit_form_extra_elements(&$form, $node_form) {

  if ($node_form) {
    $type = $form['#node']->type;
    $enabled_menus = variable_get('menu_options_' . $type, array('main-menu' => 'main-menu'));
    $enabled_menu = FALSE;
    foreach($enabled_menus as $enabled) {
      if($enabled) { 
        $enabled_menu = TRUE;
        break;
      }
    }
    if(!$enabled_menu) {
      return;
    }

?>

Does anyone still get this error?

The variable menu_options_NODE_TYPE is always created by Drupal core even when no menu is checked in the content type settings.
To prevent this error it's even better to change

variable_get('menu_options_' . $type, array('main-menu' => 'main-menu'));

to

variable_get('menu_options_' . $type, FALSE);

In that case $enabled_menus is empty when the variable does not exist.

In that case the issue will persist if the variable exists, but none of the menus are selected for the node type. The variable will return

<?php
array('main-menu' => 0)
?>

if you deselect the default option. In other words, the check should be on non-zero values.

I have another solution: replace
if (empty($enabled_menus)) {
with
if (empty($enabled_menus) || count(array_filter($enabled_menus)) == 0) {

The last patch (6) for this, no longer applies to do update in #2320615. The proposed solution better handles the return case, by checking for only non zero values. The attached patch should resolve this based on the thread. I additionally updated

 variable_get('menu_options_' . $type, array('main-menu' => 'main-menu')); 

to

variable_get('menu_options_' . $type); 

to use the default value NULL not FALSE since this provides the same result from empty().

#13 results in a PHP error:
Fatal error: Can't use function return value in write context in menu_target/menu_target.admin.inc on line 19
This is because the result of array_filter() is sent directly to empty().

The patch looks good, marking as RTBC.

Committed and created a new version, thnx!

I believe the wrong patch was committed resulting in version 1.7 having a fatal error on install.

Looks like #13 was committed not #15 which does work.

Can confirm - most recent version causes fatal error when visiting update.php after installing, had to roll back to previous version.

@Oostie Can this be fixed with #15 and released?