Issue #1959122 by Crell, tim.plunkett, chx: Fixed Optional params are not possible in routes.

core/lib/Drupal/Core/Routing/RouteProvider.php

@@ -206,7 +206,7 @@ public function getCandidateOutlines(array $parts) {
 
     // The highest possible mask is a 1 bit for every part of the path. We will
     // check every value down from there to generate a possible outline.
-    $masks = range($end, pow($number_parts - 1, 2));
+    $masks = range($end, 0);
 
     // Only examine patterns that actually exist as router items (the masks).
     foreach ($masks as $i) {

core/modules/system/lib/Drupal/system/Tests/Routing/RouteProviderTest.php

@@ -66,11 +66,15 @@ public function testCandidateOutlines() {
 
     $candidates = array_flip($candidates);
 
-    $this->assertTrue(count($candidates) == 4, 'Correct number of candidates found');
+    $this->assertTrue(count($candidates) == 8, 'Correct number of candidates found');
     $this->assertTrue(array_key_exists('/node/5/edit', $candidates), 'First candidate found.');
     $this->assertTrue(array_key_exists('/node/5/%', $candidates), 'Second candidate found.');
     $this->assertTrue(array_key_exists('/node/%/edit', $candidates), 'Third candidate found.');
     $this->assertTrue(array_key_exists('/node/%/%', $candidates), 'Fourth candidate found.');
+    $this->assertTrue(array_key_exists('/node/5', $candidates), 'Fifth candidate found.');
+    $this->assertTrue(array_key_exists('/node/%', $candidates), 'Sixth candidate found.');
+    $this->assertTrue(array_key_exists('/node', $candidates), 'Seventh candidate found.');
+    $this->assertTrue(array_key_exists('/', $candidates), 'Eighth candidate found.');
   }
 
   /**
@@ -246,6 +250,7 @@ function testOutlinePathMatchDefaultsCollision2() {
       'value' => 'poink',
     )));
     $collection->add('narf', new Route('/some/path/here'));
+    $collection->add('eep', new Route('/something/completely/different'));
 
     $dumper = new MatcherDumper($connection, 'test_routes');
     $dumper->addRoutes($collection);
@@ -258,13 +263,10 @@ function testOutlinePathMatchDefaultsCollision2() {
     try {
       $routes = $provider->getRouteCollectionForRequest($request);
 
-      // All of the matching paths have the correct pattern.
-      foreach ($routes as $route) {
-        $this->assertEqual($route->compile()->getPatternOutline(), '/some/path/here', 'Found path has correct pattern');
-      }
-
-      $this->assertEqual(count($routes), 1, 'The correct number of routes was found.');
+      $this->assertEqual(count($routes), 2, 'The correct number of routes was found.');
       $this->assertNotNull($routes->get('narf'), 'The first matching route was found.');
+      $this->assertNotNull($routes->get('poink'), 'The second matching route was found.');
+      $this->assertNull($routes->get('eep'), 'Noin-matching route was not found.');
     }
     catch (ResourceNotFoundException $e) {
       $this->fail('No matching route found with default argument value.');

core/modules/system/lib/Drupal/system/Tests/Routing/RouterTest.php

@@ -79,6 +79,7 @@ public function testControllerPlaceholders() {
    */
   public function testControllerPlaceholdersDefaultValues() {
     $this->drupalGet('router_test/test4');
+    $this->assertResponse(200);
     $this->assertRaw('narf', 'The correct string was returned because the route was successful.');
 
     // Confirm that the page wrapping is being added, so we're not getting a
@@ -90,6 +91,23 @@ public function testControllerPlaceholdersDefaultValues() {
     $this->assertNoPattern('#</body>.*</body>#s', 'There was no double-page effect from a misrendered subrequest.');
   }
 
+  /**
+   * Confirms that default placeholders in paths work correctly.
+   */
+  public function testControllerPlaceholdersDefaultValuesProvided() {
+    $this->drupalGet('router_test/test4/barf');
+    $this->assertResponse(200);
+    $this->assertRaw('barf', 'The correct string was returned because the route was successful.');
+
+    // Confirm that the page wrapping is being added, so we're not getting a
+    // raw body returned.
+    $this->assertRaw('</html>', 'Page markup was found.');
+
+    // In some instances, the subrequest handling may get confused and render
+    // a page inception style.  This test verifies that is not happening.
+    $this->assertNoPattern('#</body>.*</body>#s', 'There was no double-page effect from a misrendered subrequest.');
+  }
+
   /**
    * Checks that dynamically defined and altered routes work correctly.
    *