[Router] allow to use \A and \z as regex start and end

src/Symfony/Component/Routing/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 -----
 
  * Added support for inline definition of requirements and defaults for host
+ * Added support for `\A` and `\z` as regex start and end for route requirement
 
 5.1.0
 -----

src/Symfony/Component/Routing/Route.php

@@ -553,12 +553,18 @@ class Route implements \Serializable
 
     private function sanitizeRequirement(string $key, string $regex)
     {
-        if ('' !== $regex && '^' === $regex[0]) {
-            $regex = (string) substr($regex, 1); // returns false for a single character
+        if ('' !== $regex) {
+            if ('^' === $regex[0]) {
+                $regex = substr($regex, 1);
+            } elseif (0 === strpos($regex, '\\A')) {
+                $regex = substr($regex, 2);
+            }
         }
 
         if ('$' === substr($regex, -1)) {
             $regex = substr($regex, 0, -1);
+        } elseif (\strlen($regex) - 2 === strpos($regex, '\\z')) {
+            $regex = substr($regex, 0, -2);
         }
 
         if ('' === $regex) {

src/Symfony/Component/Routing/Tests/RouteTest.php

@@ -122,6 +122,14 @@ class RouteTest extends TestCase
         $this->assertTrue($route->hasRequirement('foo'), '->hasRequirement() return true if requirement is set');
     }
 
+    public function testRequirementAlternativeStartAndEndRegexSyntax()
+    {
+        $route = new Route('/{foo}');
+        $route->setRequirement('foo', '\A\d+\z');
+        $this->assertEquals('\d+', $route->getRequirement('foo'), '->setRequirement() removes \A and \z from the path');
+        $this->assertTrue($route->hasRequirement('foo'));
+    }
+
     /**
      * @dataProvider getInvalidRequirements
      */
@@ -139,6 +147,9 @@ class RouteTest extends TestCase
            ['^$'],
            ['^'],
            ['$'],
+           ['\A\z'],
+           ['\A'],
+           ['\z'],
         ];
     }