bug #29297 [Routing] fix trailing slash redirection when using RedirectableUrlMatcher (nicolas-grekas)

This PR was merged into the 3.4 branch.

Discussion
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[Routing] fix trailing slash redirection when using RedirectableUrlMatcher

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #29287
| License       | MIT
| Doc PR        | -

This fixes #29287 by considering that the behavior of the dumped matcher is the correct one: lower priority routes never impact previous ones. I think it's what makes the most sense because that's what requires the most local knowledge to understand what's going on (ie that's the less surprising behavior).

Commits
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dc4c3f6927 [Routing] fix trailing slash redirection when using RedirectableUrlMatcher

src/Symfony/Component/Routing/Matcher/UrlMatcher.php

@@ -118,16 +118,37 @@ class UrlMatcher implements UrlMatcherInterface, RequestMatcherInterface
      */
     protected function matchCollection($pathinfo, RouteCollection $routes)
     {
+        $supportsTrailingSlash = '/' !== $pathinfo && '' !== $pathinfo && $this instanceof RedirectableUrlMatcherInterface;
+
         foreach ($routes as $name => $route) {
             $compiledRoute = $route->compile();
+            $staticPrefix = $compiledRoute->getStaticPrefix();
 
             // check the static prefix of the URL first. Only use the more expensive preg_match when it matches
-            if ('' !== $compiledRoute->getStaticPrefix() && 0 !== strpos($pathinfo, $compiledRoute->getStaticPrefix())) {
+            if ('' === $staticPrefix || 0 === strpos($pathinfo, $staticPrefix)) {
+                // no-op
+            } elseif (!$supportsTrailingSlash) {
+                continue;
+            } elseif ('/' === substr($staticPrefix, -1) && substr($staticPrefix, 0, -1) === $pathinfo) {
+                return;
+            } else {
+                continue;
+            }
+            $regex = $compiledRoute->getRegex();
+
+            if ($supportsTrailingSlash && $pos = strpos($regex, '/$')) {
+                $regex = substr($regex, 0, $pos).'/?$'.substr($regex, $pos + 2);
+                $hasTrailingSlash = true;
+            } else {
+                $hasTrailingSlash = false;
+            }
+
+            if (!preg_match($regex, $pathinfo, $matches)) {
                 continue;
             }
 
-            if (!preg_match($compiledRoute->getRegex(), $pathinfo, $matches)) {
-                continue;
+            if ($hasTrailingSlash && '/' !== substr($pathinfo, -1)) {
+                return;
             }
 
             $hostMatches = array();

src/Symfony/Component/Routing/Tests/Matcher/RedirectableUrlMatcherTest.php

@@ -117,6 +117,17 @@ class RedirectableUrlMatcherTest extends UrlMatcherTest
         $this->assertSame(array('_route' => 'foo'), $matcher->match('/foo'));
     }
 
+    public function testFallbackPage()
+    {
+        $coll = new RouteCollection();
+        $coll->add('foo', new Route('/foo/'));
+        $coll->add('bar', new Route('/{name}'));
+
+        $matcher = $this->getUrlMatcher($coll);
+        $matcher->expects($this->once())->method('redirect')->with('/foo/')->will($this->returnValue(array('_route' => 'foo')));
+        $this->assertSame(array('_route' => 'foo'), $matcher->match('/foo'));
+    }
+
     protected function getUrlMatcher(RouteCollection $routes, RequestContext $context = null)
     {
         return $this->getMockForAbstractClass('Symfony\Component\Routing\Matcher\RedirectableUrlMatcher', array($routes, $context ?: new RequestContext()));