Issues with translation

It happens the same with _invite_get_email_template()
For me this patch resolves the issue. The main point is to change the t() position to variable_get:

Index: invite.module
===================================================================
--- invite.module	(revision 2)
+++ invite.module	(working copy)
@@ -1551,14 +1551,14 @@
  *   The localized e-mail body.
  */
 function _invite_get_mail_template() {
-  $template = t("[invite:inviter-raw] has invited you to join [site:name] at [site:url].
+  $template = "[invite:inviter-raw] has invited you to join [site:name] at [site:url].
 
 To become a member of [site:name], click the link below or paste it into the address bar of your browser.
 
 [invite:join-link]
-");
+";
 
-  return variable_get('invite_default_mail_template', $template);
+  return t(variable_get('invite_default_mail_template', $template));
 }
 
 /**

The integration with the Variable module seems to have been modified since the issue submission date.

Variables must be declared in a separated file (invite.variable.inc). Here the code I've written to use Variable with Invite :

<?php

/**
 * @file
 * Definition of variables for Variable API module.
 */

/**
 * Implements hook_variable_info().
 */
function invite_variable_info($options) {
  $variables['invite_subject'] = array(
    'type' => 'string',
    'title' => t('Invite email subject', array(), $options),
    'default' => t('[invite:inviter-raw] has sent you an invite!'),
    'description' => t('The email default subject'),
    'required' => TRUE,
    'group' => 'invite',
    'localize' => TRUE
  );

  $variables['invite_default_mail_template'] = array(
    'type' => 'string',
    'title' => t('Mail template', array(), $options),
    'default' => _invite_get_mail_template(),
    'description' => t('The email default content'),
    'required' => TRUE,
    'group' => 'invite',
    'localize' => TRUE
  );

  $variables['invite_page_title'] = array(
  		'type' => 'string',
  		'title' => t('Page title', array(), $options),
  		'default' => t('Invite a friend'),
  		'description' => t('The invite page title'),
  		'required' => TRUE,
  		'group' => 'invite',
  		'localize' => TRUE
  );

  return $variables;
}

/**
 * Implements hook_variable_group_info().
 */
function invite_variable_group_info() {
  $groups['invite'] = array(
    'title' => t('Invite'),
    'description' => t('Configure the Invite module.'),
    'access' => 'administer site configuration',
    'path' => array('admin/config/people/invite'),
  );

  return $groups;
}

Please give me a feedback for this hack.

I patched invite 7.x-2.1-beta2 with comment #1 and #2, and it's working great. Thanks for your sharing, miqmago & basilic. Hope it can be merged into future release.

Using Invite 7.x-4.0-beta2, I do not run into this issue with the default configuration, but when I check off "Invite By Mail" as the Sending method at admin/structure/invite-types/manage/invite_by_email, suddenly my subject and body are not translated. :-( It seems that the problem has gone away in the main Invite module, but still exists in the invite_by_email submodule.

My solution is similar to the one @miqmago suggested in #1 above: put variable_get() inside t(). This has a disadvantage that the strings will not be extracted when you generate PO files. (This is why you are supposed to use t() with literal strings.) For the site I am working on, we manage the PO files and keep them in a git repository, so this is not too bad.

Integrating with the Variable and i18n_variable modules, as in @basillic's comment #2 above, is another approach. It will work better for some sites, but I do not know how to manage translations using PO files and this approach.

I have attached a little patch.

@benjifisher, to clarify my method : I don't use PO files to translate realm variables (i18n_variables). I translate realm variables with the admin interface (on my dev site) and use the module features_translations to deploy all the translated variables to the testing and production sites.

Adding patch for 7.x-2.x-dev based on #3.

Adding new correct patch that also adds file from #2

Patch from #7 fails

patching file invite.module
Hunk #1 FAILED at 1571.
Hunk #2 FAILED at 1580.

For 7.x-4.x (patch #4), would prefer Variable integration via i18n.

7.x-2.x is currently not supported and no maintainer.

@basillic has it right you should not be translating a variable.

Rolling his code in a patch after fixing a few items. (7.x-4.0-beta2) release.