Fix error where routes would be incorrectly parsed.

Instead of only trying the first path partition, we should check each
matching prefix slice until all path prefixes have been exhausted.

Fixes #3954

src/Routing/RouteCollection.php

@@ -93,25 +93,25 @@ public function add(Route $route, $options = []) {
  */
 	public function parse($url) {
 		foreach (array_keys($this->_paths) as $path) {
-			if (strpos($url, $path) === 0) {
-				break;
+			if (strpos($url, $path) !== 0) {
+				continue;
 			}
-		}
 
-		$queryParameters = null;
-		if (strpos($url, '?') !== false) {
-			list($url, $queryParameters) = explode('?', $url, 2);
-			parse_str($queryParameters, $queryParameters);
-		}
-		foreach ($this->_paths[$path] as $route) {
-			$r = $route->parse($url);
-			if ($r === false) {
-				continue;
+			$queryParameters = null;
+			if (strpos($url, '?') !== false) {
+				list($url, $queryParameters) = explode('?', $url, 2);
+				parse_str($queryParameters, $queryParameters);
 			}
-			if ($queryParameters) {
-				$r['?'] = $queryParameters;
+			foreach ($this->_paths[$path] as $route) {
+				$r = $route->parse($url);
+				if ($r === false) {
+					continue;
+				}
+				if ($queryParameters) {
+					$r['?'] = $queryParameters;
+				}
+				return $r;
 			}
-			return $r;
 		}
 		throw new MissingRouteException(['url' => $url]);
 	}

tests/TestCase/Routing/RouteCollectionTest.php

@@ -101,6 +101,28 @@ public function testParse() {
 		$this->assertEquals($expected, $result);
 	}
 
+/**
+ * Test that parsing checks all the related path scopes.
+ *
+ * @return void
+ */
+	public function testParseFallback() {
+		$routes = new RouteBuilder($this->collection, '/', []);
+
+		$routes->resources('Articles');
+		$routes->connect('/:controller', ['action' => 'index'], [], ['routeClass' => 'InflectedRoute']);
+		$routes->connect('/:controller/:action', [], ['routeClass' => 'InflectedRoute']);
+
+		$result = $this->collection->parse('/articles/add');
+		$expected = [
+			'controller' => 'Articles',
+			'action' => 'add',
+			'plugin' => null,
+			'pass' => []
+		];
+		$this->assertEquals($expected, $result);
+	}
+
 /**
  * Test match() throws an error on unknown routes.
  *