Merge branch '0.9.x' into twitstream

16 files changed, 428 insertions, 123 deletions

diff --git a/lib/apiaction.php b/lib/apiaction.php
index 0ebf88282..afba8ab63 100644
--- a/lib/apiaction.php
+++ b/lib/apiaction.php
@@ -1244,23 +1244,29 @@ class ApiAction extends Action
 
         // Do not emit error header for JSONP
         if (!isset($this->callback)) {
-            header('HTTP/1.1 '.$code.' '.$status_string);
+            header('HTTP/1.1 ' . $code . ' ' . $status_string);
         }
 
-        if ($format == 'xml') {
+        switch($format) {
+        case 'xml':
             $this->initDocument('xml');
             $this->elementStart('hash');
             $this->element('error', null, $msg);
             $this->element('request', null, $_SERVER['REQUEST_URI']);
             $this->elementEnd('hash');
             $this->endDocument('xml');
-        } elseif ($format == 'json'){
+            break;
+        case 'json':
             $this->initDocument('json');
             $error_array = array('error' => $msg, 'request' => $_SERVER['REQUEST_URI']);
             print(json_encode($error_array));
             $this->endDocument('json');
-        } else {
-
+            break;
+        case 'text':
+            header('Content-Type: text/plain; charset=utf-8');
+            print $msg;
+            break;
+        default:
             // If user didn't request a useful format, throw a regular client error
             throw new ClientException($msg, $code);
         }
diff --git a/lib/apioauth.php b/lib/apioauth.php
index 1c87e4232..54cecf92a 100644
--- a/lib/apioauth.php
+++ b/lib/apioauth.php
@@ -30,13 +30,12 @@
 if (!defined('STATUSNET')) {
     exit(1);
 }
-
+require_once INSTALLDIR . '/lib/apiaction.php';
 require_once INSTALLDIR . '/lib/apioauthstore.php';
 
 /**
- * Base action for API OAuth enpoints.  Clean up the
- * the request, and possibly some other common things
- * here.
+ * Base action for API OAuth enpoints. Clean up the
+ * request. Some other common functions.
  *
  * @category API
  * @package  StatusNet
@@ -44,7 +43,7 @@ require_once INSTALLDIR . '/lib/apioauthstore.php';
  * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
  * @link     http://status.net/
  */
-class ApiOauthAction extends Action
+class ApiOauthAction extends ApiAction
 {
     /**
      * Is this a read-only action?
@@ -77,6 +76,12 @@ class ApiOauthAction extends Action
         self::cleanRequest();
     }
 
+    /*
+     * Clean up the request so the OAuth library doesn't find
+     * any extra parameters or anything else it's not expecting.
+     * I'm looking at you, p parameter.
+     */
+
     static function cleanRequest()
     {
         // kill evil effects of magical slashing
@@ -86,31 +91,19 @@ class ApiOauthAction extends Action
         }
 
         // strip out the p param added in index.php
-
-        // XXX: should we strip anything else?  Or alternatively
-        // only allow a known list of params?
         unset($_GET['p']);
         unset($_POST['p']);
-    }
+        unset($_REQUEST['p']);
 
-    function getCallback($url, $params)
-    {
-        foreach ($params as $k => $v) {
-            $url = $this->appendQueryVar($url,
-                                         OAuthUtil::urlencode_rfc3986($k),
-                                         OAuthUtil::urlencode_rfc3986($v));
+        $queryArray = explode('&', $_SERVER['QUERY_STRING']);
+
+        for ($i = 0; $i < sizeof($queryArray); $i++) {
+            if (substr($queryArray[$i], 0, 2) == 'p=') {
+                unset($queryArray[$i]);
+            }
         }
 
-        return $url;
+        $_SERVER['QUERY_STRING'] = implode('&', $queryArray);
     }
 
-    function appendQueryVar($url, $k, $v) {
-        $url = preg_replace('/(.*)(\?|&)' . $k . '=[^&]+?(&)(.*)/i', '$1$2$4', $url . '&');
-        $url = substr($url, 0, -1);
-        if (strpos($url, '?') === false) {
-            return ($url . '?' . $k . '=' . $v);
-        } else {
-            return ($url . '&' . $k . '=' . $v);
-        }
-    }
 }
diff --git a/lib/apioauthstore.php b/lib/apioauthstore.php
index eca93866f..f3bf0b857 100644
--- a/lib/apioauthstore.php
+++ b/lib/apioauthstore.php
@@ -71,33 +71,37 @@ class ApiStatusNetOAuthDataStore extends StatusNetOAuthDataStore
         }
     }
 
-    function new_access_token($token, $consumer)
+    function new_access_token($token, $consumer, $verifier)
     {
-        common_debug('new_access_token("'.$token->key.'","'.$consumer->key.'")', __FILE__);
+        common_debug(
+            'new_access_token("' . $token->key . '","' . $consumer->key. '","' . $verifier . '")',
+             __FILE__
+        );
 
         $rt = new Token();
+
         $rt->consumer_key = $consumer->key;
-        $rt->tok = $token->key;
-        $rt->type = 0; // request
+        $rt->tok          = $token->key;
+        $rt->type         = 0; // request
 
         $app = Oauth_application::getByConsumerKey($consumer->key);
+        assert(!empty($app));
 
-        if (empty($app)) {
-            common_debug("empty app!");
-        }
+        if ($rt->find(true) && $rt->state == 1 && $rt->verifier == $verifier) { // authorized
 
-        if ($rt->find(true) && $rt->state == 1) { // authorized
             common_debug('request token found.', __FILE__);
 
             // find the associated user of the app
 
             $appUser = new Oauth_application_user();
+
             $appUser->application_id = $app->id;
-            $appUser->token = $rt->tok;
+            $appUser->token          = $rt->tok;
+
             $result = $appUser->find(true);
 
             if (!empty($result)) {
-                common_debug("Oath app user found.");
+                common_debug("Ouath app user found.");
             } else {
                 common_debug("Oauth app user not found. app id $app->id token $rt->tok");
                 return null;
@@ -106,10 +110,12 @@ class ApiStatusNetOAuthDataStore extends StatusNetOAuthDataStore
             // go ahead and make the access token
 
             $at = new Token();
-            $at->consumer_key = $consumer->key;
-            $at->tok = common_good_rand(16);
-            $at->secret = common_good_rand(16);
-            $at->type = 1; // access
+            $at->consumer_key      = $consumer->key;
+            $at->tok               = common_good_rand(16);
+            $at->secret            = common_good_rand(16);
+            $at->type              = 1; // access
+            $at->verifier          = $verifier;
+            $at->verified_callback = $rt->verified_callback; // 1.0a
             $at->created = DB_DataObject_Cast::dateTime();
 
             if (!$at->insert()) {
@@ -183,4 +189,40 @@ class ApiStatusNetOAuthDataStore extends StatusNetOAuthDataStore
             throw new Exception(_('Failed to delete revoked token.'));
         }
     }
+
+    /*
+     * Create a new request token. Overrided to support OAuth 1.0a callback
+     *
+     * @param OAuthConsumer $consumer the OAuth Consumer for this token
+     * @param string        $callback the verified OAuth callback URL
+     *
+     * @return OAuthToken   $token a new unauthorized OAuth request token
+     */
+
+    function new_request_token($consumer, $callback)
+    {
+        $t = new Token();
+        $t->consumer_key = $consumer->key;
+        $t->tok = common_good_rand(16);
+        $t->secret = common_good_rand(16);
+        $t->type = 0; // request
+        $t->state = 0; // unauthorized
+        $t->verified_callback = $callback;
+
+        if ($callback === 'oob') {
+            // six digit pin
+            $t->verifier = mt_rand(0, 9999999);
+        } else {
+            $t->verifier = common_good_rand(8);
+        }
+
+        $t->created = DB_DataObject_Cast::dateTime();
+        if (!$t->insert()) {
+            return null;
+        } else {
+            return new OAuthToken($t->tok, $t->secret);
+        }
+    }
+
+
 }
diff --git a/lib/clienterroraction.php b/lib/clienterroraction.php
index 08bced5bd..9233c9bde 100644
--- a/lib/clienterroraction.php
+++ b/lib/clienterroraction.php
@@ -12,7 +12,7 @@
  * @link     http://status.net/
  *
  * StatusNet - the distributed open-source microblogging tool
- * Copyright (C) 2008, 2009, StatusNet, Inc.
+ * Copyright (C) 2008-2010 StatusNet, Inc.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as published by
@@ -32,7 +32,7 @@ if (!defined('STATUSNET') && !defined('LACONICA')) {
     exit(1);
 }
 
-require_once INSTALLDIR.'/lib/error.php';
+require_once INSTALLDIR . '/lib/error.php';
 
 /**
  * Class for displaying HTTP client errors
@@ -90,4 +90,26 @@ class ClientErrorAction extends ErrorAction
 
         $this->showPage();
     }
+
+    /**
+     *  To specify additional HTTP headers for the action
+     *
+     *  @return void
+     */
+    function extraHeaders()
+    {
+        $status_string = @self::$status[$this->code];
+        header('HTTP/1.1 '.$this->code.' '.$status_string);
+    }
+
+    /**
+     * Page title.
+     *
+     * @return page title
+     */
+
+    function title()
+    {
+        return @self::$status[$this->code];
+    }
 }
diff --git a/lib/connectsettingsaction.php b/lib/connectsettingsaction.php
index bb2e86176..325276c5f 100644
--- a/lib/connectsettingsaction.php
+++ b/lib/connectsettingsaction.php
@@ -116,9 +116,9 @@ class ConnectSettingsNav extends Widget
             }
 
             $menu['oauthconnectionssettings'] = array(
-                // TRANS: Menu item for OAth connection settings.
+                // TRANS: Menu item for OuAth connection settings.
                 _m('MENU','Connections'),
-                // TRANS: Tooltip for connected applications (Connections through OAth) menu item.
+                // TRANS: Tooltip for connected applications (Connections through OAuth) menu item.
                 _('Authorized connected applications')
             );
 
diff --git a/lib/deletegroupform.php b/lib/deletegroupform.php
new file mode 100644
index 000000000..9d8012d33
--- /dev/null
+++ b/lib/deletegroupform.php
@@ -0,0 +1,123 @@
+<?php
+/**
+ * StatusNet, the distributed open-source microblogging tool
+ *
+ * Form for joining a group
+ *
+ * PHP version 5
+ *
+ * LICENCE: This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * @category  Form
+ * @package   StatusNet
+ * @author    Evan Prodromou <evan@status.net>
+ * @author    Sarven Capadisli <csarven@status.net>
+ * @author    Brion Vibber <brion@status.net>
+ * @copyright 2009, 2010 StatusNet, Inc.
+ * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link      http://status.net/
+ */
+
+if (!defined('STATUSNET')) {
+    exit(1);
+}
+
+/**
+ * Form for deleting a group
+ *
+ * @category Form
+ * @package  StatusNet
+ * @author   Evan Prodromou <evan@status.net>
+ * @author   Sarven Capadisli <csarven@status.net>
+ * @author   Brion Vibber <brion@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
+ * @link     http://status.net/
+ *
+ * @see      UnsubscribeForm
+ * @fixme    merge a bunch of this stuff with similar form types to reduce boilerplate
+ */
+
+class DeleteGroupForm extends Form
+{
+    /**
+     * group for user to delete
+     */
+
+    var $group = null;
+
+    /**
+     * Constructor
+     *
+     * @param HTMLOutputter $out   output channel
+     * @param group         $group group to join
+     */
+
+    function __construct($out=null, $group=null)
+    {
+        parent::__construct($out);
+
+        $this->group = $group;
+    }
+
+    /**
+     * ID of the form
+     *
+     * @return string ID of the form
+     */
+
+    function id()
+    {
+        return 'group-delete-' . $this->group->id;
+    }
+
+    /**
+     * class of the form
+     *
+     * @return string of the form class
+     */
+
+    function formClass()
+    {
+        return 'form_group_delete';
+    }
+
+    /**
+     * Action of the form
+     *
+     * @return string URL of the action
+     */
+
+    function action()
+    {
+        return common_local_url('deletegroup',
+                                array('id' => $this->group->id));
+    }
+
+    function formData()
+    {
+        $this->out->hidden($this->id() . '-returnto-action', 'groupbyid', 'returnto-action');
+        $this->out->hidden($this->id() . '-returnto-id', $this->group->id, 'returnto-id');
+    }
+
+    /**
+     * Action elements
+     *
+     * @return void
+     */
+
+    function formActions()
+    {
+        $this->out->submit('submit', _('Delete'));
+    }
+}
diff --git a/lib/error.php b/lib/error.php
index a6a29119f..762425dc4 100644
--- a/lib/error.php
+++ b/lib/error.php
@@ -33,6 +33,8 @@ if (!defined('STATUSNET') && !defined('LACONICA')) {
     exit(1);
 }
 
+require_once INSTALLDIR . '/lib/info.php';
+
 /**
  * Base class for displaying HTTP errors
  *
@@ -42,7 +44,7 @@ if (!defined('STATUSNET') && !defined('LACONICA')) {
  * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
  * @link     http://status.net/
  */
-class ErrorAction extends Action
+class ErrorAction extends InfoAction
 {
     static $status = array();
 
@@ -52,7 +54,7 @@ class ErrorAction extends Action
 
     function __construct($message, $code, $output='php://output', $indent=null)
     {
-        parent::__construct($output, $indent);
+        parent::__construct(null, $message, $output, $indent);
 
         $this->code = $code;
         $this->message = $message;
@@ -64,43 +66,6 @@ class ErrorAction extends Action
         $this->prepare($_REQUEST);
     }
 
-    /**
-     *  To specify additional HTTP headers for the action
-     *
-     *  @return void
-     */
-    function extraHeaders()
-    {
-        $status_string = @self::$status[$this->code];
-        header('HTTP/1.1 '.$this->code.' '.$status_string);
-    }
-
-    /**
-     * Display content.
-     *
-     * @return nothing
-     */
-    function showContent()
-    {
-        $this->element('div', array('class' => 'error'), $this->message);
-    }
-
-    /**
-     * Page title.
-     *
-     * @return page title
-     */
-
-    function title()
-    {
-        return @self::$status[$this->code];
-    }
-
-    function isReadOnly($args)
-    {
-        return true;
-    }
-
     function showPage()
     {
         if ($this->minimal) {
@@ -116,32 +81,16 @@ class ErrorAction extends Action
         exit();
     }
 
-    // Overload a bunch of stuff so the page isn't too bloated
-
-    function showBody()
+    /**
+     * Display content.
+     *
+     * @return nothing
+     */
+    function showContent()
     {
-        $this->elementStart('body', array('id' => 'error'));
-        $this->elementStart('div', array('id' => 'wrap'));
-        $this->showHeader();
-        $this->showCore();
-        $this->showFooter();
-        $this->elementEnd('div');
-        $this->elementEnd('body');
+        $this->element('div', array('class' => 'error'), $this->message);
     }
 
-    function showCore()
-    {
-        $this->elementStart('div', array('id' => 'core'));
-        $this->showContentBlock();
-        $this->elementEnd('div');
-    }
 
-    function showHeader()
-    {
-        $this->elementStart('div', array('id' => 'header'));
-        $this->showLogo();
-        $this->showPrimaryNav();
-        $this->elementEnd('div');
-    }
 
 }
diff --git a/lib/info.php b/lib/info.php
new file mode 100644
index 000000000..395c6522e
--- /dev/null
+++ b/lib/info.php
@@ -0,0 +1,118 @@
+<?php
+
+/**
+ * Information action
+ *
+ * PHP version 5
+ *
+ * @category Action
+ * @package  StatusNet
+ * @author   Zach Copley <zach@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
+ * @link     http://status.net/
+ *
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2010, StatusNet, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+if (!defined('STATUSNET') && !defined('LACONICA')) {
+    exit(1);
+}
+
+/**
+ * Base class for displaying dialog box like messages to the user
+ *
+ * @category Action
+ * @package  StatusNet
+ * @author   Zach Copley <zach@status.net>
+ * @license  http://www.fsf.org/licensing/licenses/agpl.html AGPLv3
+ * @link     http://status.net/
+ *
+ * @see ErrorAction
+ */
+
+class InfoAction extends Action
+{
+    var $message = null;
+
+    function __construct($title, $message, $output='php://output', $indent=null)
+    {
+        parent::__construct($output, $indent);
+
+        $this->message = $message;
+        $this->title   = $title;
+
+        // XXX: hack alert: usually we aren't going to
+        // call this page directly, but because it's
+        // an action it needs an args array anyway
+        $this->prepare($_REQUEST);
+    }
+    
+    /**
+     * Page title.
+     *
+     * @return page title
+     */
+
+    function title()
+    {
+        return empty($this->title) ? '' : $this->title;
+    }
+
+    function isReadOnly($args)
+    {
+        return true;
+    }
+
+    // Overload a bunch of stuff so the page isn't too bloated
+
+    function showBody()
+    {
+        $this->elementStart('body', array('id' => 'error'));
+        $this->elementStart('div', array('id' => 'wrap'));
+        $this->showHeader();
+        $this->showCore();
+        $this->showFooter();
+        $this->elementEnd('div');
+        $this->elementEnd('body');
+    }
+
+    function showCore()
+    {
+        $this->elementStart('div', array('id' => 'core'));
+        $this->showContentBlock();
+        $this->elementEnd('div');
+    }
+
+    function showHeader()
+    {
+        $this->elementStart('div', array('id' => 'header'));
+        $this->showLogo();
+        $this->showPrimaryNav();
+        $this->elementEnd('div');
+    }
+
+    /**
+     * Display content.
+     *
+     * @return nothing
+     */
+    function showContent()
+    {
+        $this->element('div', array('class' => 'info'), $this->message);
+    }
+
+}
diff --git a/lib/installer.php b/lib/installer.php
index 2eff2d85a..c046eadea 100644
--- a/lib/installer.php
+++ b/lib/installer.php
@@ -85,7 +85,11 @@ abstract class Installer
         $config = INSTALLDIR.'/config.php';
         if (file_exists($config)) {
             if (!is_writable($config) || filesize($config) > 0) {
-                $this->warning('Config file "config.php" already exists.');
+                if (filesize($config) == 0) {
+                    $this->warning('Config file "config.php" already exists and is empty, but is not writable.');
+                } else {
+                    $this->warning('Config file "config.php" already exists.');
+                }
                 $pass = false;
             }
         }
diff --git a/lib/oauthstore.php b/lib/oauthstore.php
index f3ee629fd..1c8e72500 100644
--- a/lib/oauthstore.php
+++ b/lib/oauthstore.php
@@ -55,6 +55,17 @@ class StatusNetOAuthDataStore extends OAuthDataStore
         }
     }
 
+    function getTokenByKey($token_key)
+    {
+        $t = new Token();
+        $t->tok = $token_key;
+        if ($t->find(true)) {
+            return $t;
+        } else {
+            return null;
+        }
+    }
+
     // http://oauth.net/core/1.0/#nonce
     // "The Consumer SHALL then generate a Nonce value that is unique for
     // all requests with that timestamp."
@@ -317,13 +328,18 @@ class StatusNetOAuthDataStore extends OAuthDataStore
     function add_avatar($profile, $url)
     {
         $temp_filename = tempnam(sys_get_temp_dir(), 'listener_avatar');
-        copy($url, $temp_filename);
-        $imagefile = new ImageFile($profile->id, $temp_filename);
-        $filename = Avatar::filename($profile->id,
-                                     image_type_to_extension($imagefile->type),
-                                     null,
-                                     common_timestamp());
-        rename($temp_filename, Avatar::path($filename));
+        try {
+            copy($url, $temp_filename);
+            $imagefile = new ImageFile($profile->id, $temp_filename);
+            $filename = Avatar::filename($profile->id,
+                                         image_type_to_extension($imagefile->type),
+                                         null,
+                                         common_timestamp());
+            rename($temp_filename, Avatar::path($filename));
+        } catch (Exception $e) {
+            unlink($temp_filename);
+            throw $e;
+        }
         return $profile->setOriginal($filename);
     }
 
diff --git a/lib/right.php b/lib/right.php
index deb451fde..bacbea5f2 100644
--- a/lib/right.php
+++ b/lib/right.php
@@ -60,5 +60,6 @@ class Right
     const MAKEGROUPADMIN     = 'makegroupadmin';
     const GRANTROLE          = 'grantrole';
     const REVOKEROLE         = 'revokerole';
+    const DELETEGROUP        = 'deletegroup';
 }
 
diff --git a/lib/router.php b/lib/router.php
index 00b299373..b1cc8d529 100644
--- a/lib/router.php
+++ b/lib/router.php
@@ -276,7 +276,7 @@ class Router
 
             $m->connect('group/new', array('action' => 'newgroup'));
 
-            foreach (array('edit', 'join', 'leave') as $v) {
+            foreach (array('edit', 'join', 'leave', 'delete') as $v) {
                 $m->connect('group/:nickname/'.$v,
                             array('action' => $v.'group'),
                             array('nickname' => '[a-zA-Z0-9]+'));
diff --git a/lib/servererroraction.php b/lib/servererroraction.php
index 9b5a553dc..54cc99099 100644
--- a/lib/servererroraction.php
+++ b/lib/servererroraction.php
@@ -96,4 +96,27 @@ class ServerErrorAction extends ErrorAction
 
         $this->showPage();
     }
+
+    /**
+     *  To specify additional HTTP headers for the action
+     *
+     *  @return void
+     */
+    function extraHeaders()
+    {
+        $status_string = @self::$status[$this->code];
+        header('HTTP/1.1 '.$this->code.' '.$status_string);
+    }
+
+    /**
+     * Page title.
+     *
+     * @return page title
+     */
+
+    function title()
+    {
+        return @self::$status[$this->code];
+    }
+
 }
diff --git a/lib/serverexception.php b/lib/serverexception.php
index 7dc9765ad..0dfbd04ff 100644
--- a/lib/serverexception.php
+++ b/lib/serverexception.php
@@ -22,7 +22,7 @@
  * @category  Exception
  * @package   StatusNet
  * @author    Evan Prodromou <evan@status.net>
- * @copyright 2008 StatusNet, Inc.
+ * @copyright 2008-2010 StatusNet, Inc.
  * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
  * @link      http://status.net/
  */
diff --git a/lib/statusnet.php b/lib/statusnet.php
index 7212a4a47..7cb831696 100644
--- a/lib/statusnet.php
+++ b/lib/statusnet.php
@@ -336,8 +336,11 @@ class StatusNet
 
         foreach ($config_files as $_config_file) {
             if (@file_exists($_config_file)) {
-                include($_config_file);
-                self::$have_config = true;
+                // Ignore 0-byte config files
+                if (filesize($_config_file) > 0) {
+                    include($_config_file);
+                    self::$have_config = true;
+                }
             }
         }
 
diff --git a/lib/util.php b/lib/util.php
index 35fcfdb09..c05fcf15a 100644
--- a/lib/util.php
+++ b/lib/util.php
@@ -919,7 +919,12 @@ function common_shorten_links($text, $always = false)
 function common_validate_utf8($str)
 {
     // preg_replace will return NULL on invalid UTF-8 input.
-    return preg_replace('//u', '', $str);
+    //
+    // Note: empty regex //u also caused NULL return on some
+    // production machines, but none of our test machines.
+    //
+    // This should be replaced with a more reliable check.
+    return preg_replace('/\x00/u', '', $str);
 }
 
 /**