accesslib: Fix get_context_users_bycap() when no roles grant the cap

When no roles mention the capability, get_context_users_bycap() breaks badly. This trivial patch does a sanity check before jumping into the SQL shark-pool... MDL-13160
moodle · Jan 25, 2008 · c2d88da · c2d88da
1 parent c648a22
commit c2d88da
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/lib/accesslib.php b/lib/accesslib.php
@@ -1145,6 +1145,10 @@ function get_context_users_bycap ($context, $capability='moodle/course:view', $f
     rs_close($rs);
     $roles = implode(',', $roles);
 
+    if (empty($roles)) {
+        return array();
+    }
+
     //
     // User permissions subselect SQL
     //