@lcdservices I have just tested this but it don't work for me.

How to test

• enable frontend registratration
• choose "self" registration
• go to the frontend and register an account
• click the activation link. --> Works
• got to the backend and set "admin registration"
• go to the frontend and register an account
• click the activation link. --> Works

• apply this patch

• choose "self" registration

• go to the frontend and register an account
• click the activation link. --> don't work here
• got to the backend and set "admin registration"
• go to the frontend and register an account
• click the activation link. --> don't work here.

expected result

http://www.example.org/dev/e3/index.php?option=com_users&task=registration.activate&token=ab7bc2b688beb2477c103ce4ee5b318b

actual result

http://www.example.org/index.php?option=com_users&task=registration.activate&token=ab7bc2b688beb2477c103ce4ee5b318b

I wonder if we need $base here.
Maybe we would just need `JRoute::_(JUri::root() . 'index.php?option=com_users&task=registration.activate&token=' . $data['activation'], false);

This code is wrong. And I think the solution is quite simple. We just need to remove administrator/ from $data['activate'] when this method is called from administrator area with this code

if (JFactory::getApplication()->isAdmin())
{
    $adminPos         = strrpos($data['activate'], 'administrator/');
    $data['activate'] = substr_replace($data['activate'], '', $adminPos, 14);
}

I made a small PR to your branch to make it works like that lcdservices#1. Please try to test it and if it works, please merge it so that other testers can test it

I think the suggestion from @infograf768 is much cleaner and more direct than doing a string replacement after the URL has been constructed. @zero-24 -- can you test the revised PR? I don't have a dev site set up where Joomla is installed in a subdirectory (which is the use case that created the issues you noticed).

@lcdservices While the suggestion from @infograf768 works, it always return none-sef URL. Also, I haven't seen anywhere in our core code which pass full URL into JRoute::_ method, so I don't think that the code is good enough.

hmm generaly it works but it looks like we need to fix is also here:
https://github.com/lcdservices/joomla-cms/blob/patch-1/components/com_users/models/registration.php#L85

We also get with this patch applyed:

But i have no clue why?

hmm i guess the seccond on was an error on my side. I can not reproduce this again?!

Ok. So only point on need to be fixed see:
https://github.com/lcdservices/joomla-cms/blob/patch-1/components/com_users/models/registration.php#L85

and the comment by @joomdonation

@zero-24 I think we don't have to worry at the code at activate method (which you mentioned). The reason is because usually, third party developer only uses register method to create a Joomla user in Joomla core (I use it in my extension too), but for the activate method, I think it is just handled by Joomla core (when users click on the activation link).

ok...
@zero-24 I fixed it in the additional location you identified
@joomdonation - I really don't like the string replace method -- it's too hackish. but I agree it seems the only way to do this while preserving SEF urls. So I restructured it to handle it in this way.

@lcdservices Could you merge @zero-24 PR so that travis happy and we can get this PR merged?

I use this function in my extension, too, and would love to have this merged in next release of Joomla so that I don't have to change code / fix bugs for client

done. sorry, didn't notice he had done it as a PR against my patch.

RTC based on testing

Any reason not to use a simpler:
$data['activate'] = str_replace('administrator/', '', $data['activate'])
instead of looking for its position?

Might have bug in case you you have a site called administrator

for example, http://localhost/administrator/administrator

Of course it will only happens in that very special case but we should avoid that.