Reject SCP-style URIs with explicit protocols in Diffusion

Summary:
Fixes T3619. These URIs are valid:

  git@domain.com:/path        (Git SCP-style implicit SSH)
  ssh://git@domain.com/path   (Explicit SSH)

This URI, arrived at by adding "ssh://" to the front of an SCP-style URI, is not:

  ssh://git@domain.com:/path

Detect URIs in this form and reject them. See T3619.

Test Plan:
{F75486}

Also set some valid URIs.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3619

Differential Revision: https://secure.phabricator.com/D7431

src/applications/diffusion/controller/DiffusionRepositoryCreateController.php

@@ -457,6 +457,21 @@ final class DiffusionRepositoryCreateController
         }
       }
 
+      // Catch confusion between Git/SCP-style URIs and normal URIs. See T3619
+      // for discussion. This is usually a user adding "ssh://" to an implicit
+      // SSH Git URI.
+      if ($proto == 'ssh') {
+        if (preg_match('(^[^:@]+://[^/:]+:[^\d])', $v_remote)) {
+          $c_remote->setError(pht('Invalid'));
+          $page->addPageError(
+            pht(
+              "The Remote URI is not formatted correctly. Remote URIs ".
+              "with an explicit protocol should be in the form ".
+              "'proto://domain/path', not 'proto://domain:/path'. ".
+              "The ':/path' syntax is only valid in SCP-style URIs."));
+        }
+      }
+
       switch ($proto) {
         case 'ssh':
         case 'http':