Allow overriding views to override paths with parameters

The patch contains #2098197: Add getAllRoutes() method to RouteProvider .

1. +++ b/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php
   @@ -223,6 +225,22 @@ public function alterRoutes(RouteCollection $collection) {
   +        $argument_ids = array_keys($view_arguments);
   ...
   +          $path = str_replace('arg_' . $argument_ids[$key], $parameter, $path);
   

   I know this works, it just seems a bit fragile. I can't see a better way though unfortunately. Maybe some comment about the numeric keys matching up would help?

2. +++ b/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php
   @@ -223,6 +225,22 @@ public function alterRoutes(RouteCollection $collection) {
   +        foreach ($parameters as $key => $parameter) {
   

   Maybe these vars could be named better. Not sure of anything better right now though :p But the key is the parameter position? and the parameter is actually the param node (that would be in the slug) right?

3. +++ b/core/modules/views/lib/Drupal/views/Routing/ViewPageController.php
   @@ -65,15 +66,32 @@ public function handle(Request $request) {
   +      // Allow parameters be pulled from
   

   I think this line needs to be finished off? :)

4. +++ b/core/modules/views/lib/Drupal/views/Routing/ViewPageController.php
   @@ -65,15 +66,32 @@ public function handle(Request $request) {
   +      else {
   +        $arg = $request->attributes->get($attribute);
   +      }
   

   So if it gets to here, it's just a regular views arg, yes?

5. +++ b/core/modules/views/tests/Drupal/views/Tests/Plugin/display/PathPluginBaseTest.php
   @@ -146,6 +146,42 @@ public function testAlterRoute() {
   +    // Manually setup a argument handler.
   

   an argument handler.

6. +++ b/core/modules/views/tests/Drupal/views/Tests/Plugin/display/PathPluginBaseTest.php
   @@ -146,6 +146,42 @@ public function testAlterRoute() {
   +    $this->assertTrue($route instanceof Route);
   

   assertInstanceOf

7. +++ b/core/modules/views/tests/Drupal/views/Tests/Routing/ViewPageControllerTest.php
   @@ -0,0 +1,266 @@
   +
   

   Extra newline.

8. +++ b/core/modules/views/tests/Drupal/views/Tests/Routing/ViewPageControllerTest.php
   @@ -0,0 +1,266 @@
   +    $this->assertTrue(is_array($output));
   

   assertInternalType?

+++ b/core/modules/views/lib/Drupal/views/Plugin/views/display/PathPluginBase.php
@@ -223,6 +225,24 @@ public function alterRoutes(RouteCollection $collection) {
+        $route->setDefault('_view_argument_map', $argument_map);

+++ b/core/modules/views/lib/Drupal/views/Routing/ViewPageController.php
@@ -65,15 +66,37 @@ public function handle(Request $request) {
+    $map = $request->attributes->get('_view_argument_map', array());

Brilliant.

This looks great, let's get it in.

Committed to 8.x. Thanks!