Allow Git and Mercurial repositories to be cloned with names in the URI

Summary:
Ref T4175. This allows these URIs to all be valid for Git and Mercurial:

  /diffusion/X/
  /diffusion/X/anything.git
  /diffusion/X/anything/

This mostly already works, it just needed a few tweaks.

Test Plan: Cloned git and hg working copies using HTTP and SSH.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T4175

Differential Revision: https://secure.phabricator.com/D8098

src/applications/diffusion/controller/DiffusionRepositoryDefaultController.php

@@ -6,6 +6,12 @@ final class DiffusionRepositoryDefaultController extends DiffusionController {
     // NOTE: This controller is just here to make sure we call
     // willBeginExecution() on any /diffusion/X/ URI, so we can intercept
     // `git`, `hg` and `svn` HTTP protocol requests.
-    return new Aphront404Response();
+
+    // If we made it here, it's probably because the user copy-pasted a
+    // clone URI with "/anything.git" at the end into their web browser.
+    // Send them to the canonical repository URI.
+
+    return id(new AphrontRedirectResponse())
+      ->setURI($this->getDiffusionRequest()->getRepository()->getURI());
   }
 }