commit 4a27ee86fdbbab5f738ce7a912a983729c7d883b
Author: fago <nuppla@zites.net>
Date:   Mon Jul 29 20:55:32 2013 +0200

    Allow modules to expose directories for other modules.

diff --git a/includes/rules.core.inc b/includes/rules.core.inc
index c512ba3..668cfa5 100644
--- a/includes/rules.core.inc
+++ b/includes/rules.core.inc
@@ -1766,9 +1766,16 @@ abstract class RulesAbstractPlugin extends RulesPlugin {
           module_load_include('inc', $module, $name);
         }
       }
+      $dirs = array();
       foreach (module_implements('rules_directory') as $module) {
         // Include all files once, so the discovery can find them.
-        $directory = module_invoke($module, 'rules_directory');
+        $result = module_invoke($module, 'rules_directory');
+        if (!is_array($result)) {
+          $result = array($module => $result);
+        }
+        $dirs += $result;
+      }
+      foreach ($dirs as $module => $directory) {
         foreach (glob(drupal_get_path('module', $module) . "/$directory/*.{inc,php}", GLOB_BRACE) as $filename) {
           include_once $filename;
         }
diff --git a/rules.api.php b/rules.api.php
index 1361007..c9a2524 100644
--- a/rules.api.php
+++ b/rules.api.php
@@ -181,11 +181,13 @@ function hook_rules_file_info() {
  * the files containing the classes during discovery - see
  * rules_discover_plugins().
  *
- * @return string
+ * @return string|array
  *   A directory relative to the module directory, which holds the files
- *   containing rules plugin handlers. All files in those directory having
- *   a 'php' or 'inc' file extension will be loaded during discovery.
- *   Optionally, wildcards ('*') may be used to match multiple directories.
+ *   containing rules plugin handlers, or multiple directories keyed by the
+ *   module the directory is contained in.
+ *   All files in those directories having a 'php' or 'inc' file extension will
+ *   be loaded during discovery. Optionally, wildcards ('*') may be used to
+ *   match multiple directories.
  *
  * @see rules_discover_plugins()
  */