[Arcanist] fix scratch dir for svn >= 1.7

Summary:
svn 1.7 got rid of the per-direcotry .svn dirs in favor of a single
.svn directory under the root of the working copy.  Unfortunately, we
relied on ther being a .svn directory at the same level as .arcconfig,
which may or may not be at the root of the working copy.  We now walk
up the directory tree until we find a .svn directory that we can use
for scratch files.

Test Plan:
[16:27:52 Mon Jun 25 2012] dschleimer@dev4022.snc6 ~/data/admin/facebook/scripts/db
db  21298 $ ls -la .arcconfig .svn ../../../.svn/arc/config
ls: .svn: No such file or directory
ls: ../../../.svn/arc/config: No such file or directory
-rw-r--r-- 1 dschleimer users 239 Jun 25 16:15 .arcconfig

[16:27:54 Mon Jun 25 2012] dschleimer@dev4022.snc6 ~/data/admin/facebook/scripts/db
db  21298 $ ~/devtools/arcanist/bin/arc set-config --local foo bar
Set key 'foo' = 'bar' in local config.

[16:29:40 Mon Jun 25 2012] dschleimer@dev4022.snc6 ~/data/admin/facebook/scripts/db
db  21298 $ ls -la .arcconfig .svn ../../../.svn/arc/config
ls: .svn: No such file or directory
-rw-r--r-- 1 dschleimer users 239 Jun 25 16:15 .arcconfig
-rw-r--r-- 1 dschleimer users  20 Jun 25 16:29 ../../../.svn/arc/config

[16:29:43 Mon Jun 25 2012] dschleimer@dev4022.snc6 ~/data/admin/facebook/scripts/db
db  21298 $ cat ../../../.svn/arc/config
{
  "foo" : "bar"
}

[16:29:48 Mon Jun 25 2012] dschleimer@dev4022.snc6 ~/data/admin/facebook/scripts/db
db  21299 $ ~/devtools/arcanist/bin/arc get-config foo
(global) foo =
(local) foo = bar

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1411

Differential Revision: https://secure.phabricator.com/D2856

src/repository/api/ArcanistSubversionAPI.php

@@ -37,7 +37,20 @@ final class ArcanistSubversionAPI extends ArcanistRepositoryAPI {
   }
 
   public function getMetadataPath() {
-    return $this->getPath('.svn');
+    static $svn_dir = null;
+    if ($svn_dir === null) {
+      // from svn 1.7, subversion keeps a single .svn directly under
+      // the working copy root.  However, we allow .arcconfigs that
+      // aren't at the working copy root.
+      foreach (Filesystem::walkToRoot($this->getPath()) as $parent) {
+        $possible_svn_dir = Filesystem::resolvePath('.svn', $parent);
+        if (Filesystem::pathExists($possible_svn_dir)) {
+          $svn_dir = $possible_svn_dir;
+          break;
+        }
+      }
+    }
+    return $svn_dir;
   }
 
   protected function buildLocalFuture(array $argv) {

src/workingcopyidentity/ArcanistWorkingCopyIdentity.php

@@ -105,17 +105,39 @@ final class ArcanistWorkingCopyIdentity {
       '.hg',
       '.svn',
     );
+    $found_meta_dir = false;
     foreach ($vc_dirs as $dir) {
-      $local_path = Filesystem::resolvePath(
+      $meta_path = Filesystem::resolvePath(
-        $dir.'/arc/config',
+        $dir,
         $this->projectRoot);
+      if (Filesystem::pathExists($meta_path)) {
+        $found_meta_dir = true;
+        $local_path = Filesystem::resolvePath(
+          'arc/config',
+          $meta_path);
         if (Filesystem::pathExists($local_path)) {
           $file = Filesystem::readFile($local_path);
           if ($file) {
             $this->localConfig = json_decode($file, true);
+          }
+        }
         break;
       }
     }
+
+    if (!$found_meta_dir) {
+      // Try for a single higher-level .svn directory as used by svn 1.7+
+      foreach (Filesystem::walkToRoot($this->projectRoot) as $parent_path) {
+        $local_path = Filesystem::resolvePath(
+          '.svn/arc/config',
+          $parent_path);
+        if (Filesystem::pathExists($local_path)) {
+          $file = Filesystem::readFile($local_path);
+          if ($file) {
+            $this->localConfig = json_decode($file, true);
+          }
+        }
+      }
     }
 
   }