Index: lib/accesslib.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/accesslib.php,v
retrieving revision 1.575
diff -u -r1.575 accesslib.php
--- lib/accesslib.php	20 Mar 2009 07:41:49 -0000	1.575
+++ lib/accesslib.php	20 Mar 2009 08:13:25 -0000
@@ -162,13 +162,42 @@
 define('ROLENAME_ORIGINALANDSHORT', 3); // the name as defined in the role definition and the shortname in brackets
 define('ROLENAME_ALIAS_RAW', 4);   // the name as defined by a role alias, in raw form suitable for editing
 
-$context_cache    = array();    // Cache of all used context objects for performance (by level and instance)
-$context_cache_id = array();    // Index to above cache by id
+// Caches. Although these are global variables, they MUST NOT be used outside accesslib.
+$context_cache = array(); // Cache of all used context objects for performance (by level and instance)
+$context_cache_id = array(); // Index to above cache by id
+$cron_cache = array(); // Used in get_role_access
+$cached_system_context = null; // Used in get_system_context
+$preloadedcourses = array(); // Used in preload_course_contexts.
+$capability_names = null; // Used in is_valid_capability
 
 $DIRTYCONTEXTS = null; // dirty contexts cache
 $ACCESS = array(); // cache of caps for cron user switching and has_capability for other users (==not $USER)
 $RDEFS = array(); // role definitions cache - helps a lot with mem usage in cron
 
+/**
+ * This method should ONLY BE USED BY UNIT TESTS. It clears all of
+ * accesslib's private caches. You need to do this before setting up test data,
+ * and also at the end fo the tests.
+ */
+function accesslib_clear_all_caches_for_unit_testing() {
+    global $UNITTEST;
+    if (empty($UNITTEST->running)) {
+        throw new coding_exception('You must not call clear_all_caches outside of unit tests.');
+    }
+    global $context_cache, $context_cache_id, $cron_cache, $cached_system_context,
+            $preloadedcourses, $capability_names, $DIRTYCONTEXTS, $ACCESS, $RDEFS;
+    $context_cache = array(); // Cache of all used context objects for performance (by level and instance)
+    $context_cache_id = array(); // Index to above cache by id
+    $cron_cache = array(); // Used in get_role_access
+    $cached_system_context = null; // Used in get_system_context
+    $preloadedcourses = array(); // Used in preload_course_contexts.
+    $capability_names = null; // Used in is_valid_capability
+
+    $DIRTYCONTEXTS = null; // dirty contexts cache
+    $ACCESS = array(); // cache of caps for cron user switching and has_capability for other users (==not $USER)
+    $RDEFS = array(); // role definitions cache - helps a lot with mem usage in cron
+}
+
 function get_role_context_caps($roleid, $context) {
     global $DB;
 
@@ -243,7 +272,7 @@
 
     // we need extra caching in CLI scripts and cron
     if (CLI_SCRIPT) {
-        static $cron_cache = array();
+        global $cron_cache;
 
         if (!isset($cron_cache[$roleid])) {
             $cron_cache[$roleid] = array();
@@ -2097,19 +2126,17 @@
  * @return mixed system context or null
  */
 function get_system_context($cache=true) {
-    global $DB;
-
-    static $cached = null;
+    global $DB, $cached_system_context;
     if ($cache and defined('SYSCONTEXTID')) {
-        if (is_null($cached)) {
-            $cached = new object();
-            $cached->id           = SYSCONTEXTID;
-            $cached->contextlevel = CONTEXT_SYSTEM;
-            $cached->instanceid   = 0;
-            $cached->path         = '/'.SYSCONTEXTID;
-            $cached->depth        = 1;
+        if (is_null($cached_system_context)) {
+            $cached_system_context = new object();
+            $cached_system_context->id           = SYSCONTEXTID;
+            $cached_system_context->contextlevel = CONTEXT_SYSTEM;
+            $cached_system_context->instanceid   = 0;
+            $cached_system_context->path         = '/'.SYSCONTEXTID;
+            $cached_system_context->depth        = 1;
         }
-        return $cached;
+        return $cached_system_context;
     }
     try {
         // TODO: can not use get_record() because we do not know if query failed :-(
@@ -2152,8 +2179,8 @@
         define('SYSCONTEXTID', $context->id);
     }
 
-    $cached = $context;
-    return $cached;
+    $cached_system_context = $context;
+    return $cached_system_context;
 }
 
 /**
@@ -2348,7 +2375,7 @@
     global $context_cache, $context_cache_id, $DB;
 
     // Users can call this multiple times without doing any harm
-    static $preloadedcourses = array();
+    global $preloadedcourses;
     if (array_key_exists($courseid, $preloadedcourses)) {
         return;
     }
@@ -3857,14 +3884,14 @@
  * @return book true if capability exists
  */
 function is_valid_capability($capabilityname, $cached=true) {
-    static $capsnames = null; // one request per page only
+    global $capability_names; // one request per page only
 
-    if (is_null($capsnames) or !$cached) {
+    if (is_null($capability_names) or !$cached) {
         global $DB;
-        $capsnames = $DB->get_records_menu('capabilities', null, '', 'name, 1');
+        $capability_names = $DB->get_records_menu('capabilities', null, '', 'name, 1');
     }
 
-    return array_key_exists($capabilityname, $capsnames);
+    return array_key_exists($capabilityname, $capability_names);
 }
 
 /**