There is a missing check for "sef" (JRoute should not used for non-sef)!
if you change/add this code at line 107 of helper.php all works fine:

 //$language->link = JRoute::('index.php?lang=' . $language->sef . '&Itemid=' . $itemid);

 // added code:

 if ($app->get('sef') == '1')

 {

   $language->link = JRoute::('index.php?lang=' . $language->sef . '&Itemid=' . $itemid);

 }

 else

 {

   $language->link = 'index.php?lang=' . $language->sef . '&Itemid=' . $itemid;


 }

https://github.com/joomla/joomla-cms/blob/staging/libraries/cms/router/site.php#L140
i thought is here? Maybe i am wrong.

hi,
do not know either - results show that obviously it is not.

JRoute should not used for non-sef

JRoute should always be used. The router classes are designed to be aware if SEF is enabled or not and react as such.

hi,
and now - what ist the problem???? I've changed code to bypass router and with this it works (by the way this is the code implementation of V3.3.6!)

@jschmi01 doesn't mean that the code of 3.3.6 is correct.

The fix for this is #6254

OK - thank you! (will stick with may circumvention until fix gets available)

Hi,
I hope my post will be usefull.
I don't know if it's the same problem as the language switcher. If not, please delete this post.
(I have created a topic on VM forum too).

I reproduced this problem in multilingual VM3 sites and Joomla! 3.4.0 (client's site and own test site too). When SEF is off, as said here, VM URLs in language switcher seems to be right, not Joomla! URLs, .
If SEF is on, language switcher has now good URLs, but another problem appears in Virtuemart: when I put a product in cart, language strings and URLs in the popup window are not in the right language. If I clic on "continue shopping" or "view cart" (in the false language) I am no more in my own language.
You can view it on http://multi.par-robertg.fr/index.php/en/shop (SEF On): change language, popup language remains the same. (I needed to regress in J! 3.3.6 on a client's site).

Robert

I have the same issue as Robert that is unresolved in 3.4.1.

I also have the same strange behavior in VirtueMart, which fontanil (Robert) reported above, when I update a Joomla 3.4.0/VM 3.0.x shop (including latest version) to Joomla 3.4.1.

However, Robert said in the comments for #6254 that "...both 6254 and 6278 patches solve language switcher URLs and language in Virtuemart popup." But somehow this problems seems to have reappeared in the J3.4.1 release.

When using the VM 'Add to Cart' button while in a different language than the site default language, the language switcher changes to the default site language. The issue is present with both, SEF urls on/off. This only happens with Joomla 3.4.1. All other Joomla 2.x/3.x combinations with VirtueMart don't have this problem.

I currently have no idea what exactly causes this behavior, because there are no error messages.

@prokopsdk
Perhaps you can add the link to your test site (which I've seen in the VM forum) here so others can see the problem 'live'. Since you seem to have set English as the site default language, the problem becomes visible when using the other languages.

Live test site: http://inlovemedia.dk/j3-341/index.php/se/
This is a clean install of J!3.4.1 and VM3.0.6.4 with SE and EN languages.

I just tested on http://multi.robertg.fr and issue has reappeared in 3.4.1 and VM 3.0.6.4

The last comment here was in April. So the question is, Is this issue still valid - there seems to be some confusion from the comments that this is a VM issue not Joomla

Closed due to lack of response to previous comment

I think this is the similar problem as I had with using &lang or not and cache issues #11470
#11470