arg(0) returns path prefix with Language Path Negotiation enabled

The actual bug is that code is using arg() but yeah things aren't simple ... see https://drupal.org/node/788900
arg() should maybe just switch to \Drupal::request()->attributes->get('system_path');

I changed the file header to say Contains \Fully\Qualified\Namespace\And\NameOfTheClass instead of Definition of as per https://drupal.org/node/1354#file

Practicing my first patch :)

I should have made the interdiff a .txt file. I will resubmit after the test completes.

Same as above but interdiff.txt

File header changed to say Contains \Fully\Qualified\Namespace\And\NameOfTheClass instead of Definition of as per https://drupal.org/node/1354#file

Looks like the last test only patch does not fail? Hum.

Looks the test is not applied as expected, let's take a look at this. Here a couple of changes.

Let's try again.

@Schnitzel sure! done. Many thanks!

Here's a diff of 15 and 17

< +            _current_path(substr(_current_path(), strlen($prefix) + 1));
---
> +            if (strpos(_current_path(), $prefix . '/') === 0) {
> +              _current_path(substr(_current_path(), strlen($prefix . '/')));
> +            }

18: 2251061-17.patch queued for re-testing.

18: 2251061-17.patch queued for re-testing.

#788900: Deprecate and remove usages of arg() (change notice at https://drupal.org/node/2274705) says arg() is deprecated. For the practicalities of this issue, _current_path() is already broken (which is suggested in place of arg() for taking path segments). So this may need to be repurposed to talk about _current_path().

About _current_path().

@todo This is a temporary function pending refactoring Drupal to use Symfony's Request object exclusively.

So, I'm not sure if we should continue working on this using that function.

that todo is #2237001: Remove no longer needed _current_path() fallback for early bootstrap
(according to #1183208-111: Remove variable_get('clean_url') and switch to index.php/path pattern for dirty URL support)

I think this patch needs to be updated per #2294093: Remove arg(). Or am I missing something?

This looks to be obsolete to me? As explained in the change notice for #2294093: Remove arg() (https://www.drupal.org/node/2274705), you would use route matching. If you have a raw path somehow early in the request and need to match the route, you can use a PathProcessor to remove unwanted things. #1833010: Admin user language preference WSOD if ahead of path prefixes has a solution that now the admin language preference uses to do the same thing before the path itself is processed later on in the request, which you can use to process your path. That will remove any language prefix, resolve aliases, and any other path mangling the negotiators may have done.