Index: modules/filter/filter.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/filter/filter.admin.inc,v
retrieving revision 1.71
diff -u -r1.71 filter.admin.inc
--- modules/filter/filter.admin.inc	14 Dec 2010 02:40:15 -0000	1.71
+++ modules/filter/filter.admin.inc	12 Feb 2011 21:42:51 -0000
@@ -231,7 +231,7 @@
   );
 
   foreach ($filter_info as $name => $filter) {
-    if (isset($filter['settings callback']) && function_exists($filter['settings callback'])) {
+    if (isset($filter['settings callback'])) {
       $function = $filter['settings callback'];
       // Pass along stored filter settings and default settings, but also the
       // format object and all filters to allow for complex implementations.
Index: modules/filter/filter.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/filter/filter.module,v
retrieving revision 1.362
diff -u -r1.362 filter.module
--- modules/filter/filter.module	14 Jan 2011 08:33:46 -0000	1.362
+++ modules/filter/filter.module	12 Feb 2011 21:42:52 -0000
@@ -746,7 +746,7 @@
 
   // Give filters the chance to escape HTML-like data such as code or formulas.
   foreach ($filters as $name => $filter) {
-    if ($filter->status && isset($filter_info[$name]['prepare callback']) && function_exists($filter_info[$name]['prepare callback'])) {
+    if ($filter->status && isset($filter_info[$name]['prepare callback'])) {
       $function = $filter_info[$name]['prepare callback'];
       $text = $function($text, $filter, $format, $langcode, $cache, $cache_id);
     }
@@ -754,7 +754,7 @@
 
   // Perform filtering.
   foreach ($filters as $name => $filter) {
-    if ($filter->status && isset($filter_info[$name]['process callback']) && function_exists($filter_info[$name]['process callback'])) {
+    if ($filter->status && isset($filter_info[$name]['process callback'])) {
       $function = $filter_info[$name]['process callback'];
       $text = $function($text, $filter, $format, $langcode, $cache, $cache_id);
     }
@@ -1012,7 +1012,7 @@
     $filters = filter_list_format($format->format);
     $tips[$format->name] = array();
     foreach ($filters as $name => $filter) {
-      if ($filter->status && isset($filter_info[$name]['tips callback']) && function_exists($filter_info[$name]['tips callback'])) {
+      if ($filter->status && isset($filter_info[$name]['tips callback'])) {
         $tip = $filter_info[$name]['tips callback']($filter, $format, $long);
         if (isset($tip)) {
           $tips[$format->name][$name] = array('tip' => $tip, 'id' => $name);
Index: modules/book/book.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/book/book.module,v
retrieving revision 1.558
diff -u -r1.558 book.module
--- modules/book/book.module	3 Jan 2011 07:34:46 -0000	1.558
+++ modules/book/book.module	12 Feb 2011 21:42:50 -0000
@@ -1143,7 +1143,7 @@
         $children = book_export_traverse($data['below'], $visit_func);
       }
 
-      if (function_exists($visit_func)) {
+      if (!empty($visit_func)) {
         $output .= call_user_func($visit_func, $node, $children);
       }
       else {
Index: modules/image/image.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/image/image.module,v
retrieving revision 1.57
diff -u -r1.57 image.module
--- modules/image/image.module	4 Feb 2011 19:43:25 -0000	1.57
+++ modules/image/image.module	12 Feb 2011 21:42:52 -0000
@@ -1071,10 +1071,7 @@
 function image_effect_apply($image, $effect) {
   module_load_include('inc', 'image', 'image.effects');
   $function = $effect['effect callback'];
-  if (function_exists($function)) {
-    return $function($image, $effect['data']);
-  }
-  return FALSE;
+  return $function($image, $effect['data']);
 }
 
 /**
Index: modules/image/image.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/image/image.admin.inc,v
retrieving revision 1.28
diff -u -r1.28 image.admin.inc
--- modules/image/image.admin.inc	21 Nov 2010 07:24:53 -0000	1.28
+++ modules/image/image.admin.inc	12 Feb 2011 21:42:52 -0000
@@ -390,9 +390,8 @@
 
   $form['#tree'] = TRUE;
   $form['#attached']['css'][drupal_get_path('module', 'image') . '/image.admin.css'] = array();
-  if (function_exists($effect['form callback'])) {
-    $form['data'] = call_user_func($effect['form callback'], $effect['data']);
-  }
+
+  $form['data'] = call_user_func($effect['form callback'], $effect['data']);
 
   // Check the URL for a weight, then the image effect, otherwise use default.
   $form['weight'] = array(
Index: modules/rdf/rdf.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/rdf/rdf.module,v
retrieving revision 1.49
diff -u -r1.49 rdf.module
--- modules/rdf/rdf.module	11 Dec 2010 02:38:24 -0000	1.49
+++ modules/rdf/rdf.module	12 Feb 2011 21:42:53 -0000
@@ -305,7 +305,7 @@
     case 'property':
       $attributes['property'] = $mapping['predicates'];
       // Convert $data to a specific format as per the callback function.
-      if (isset($data) && isset($mapping['callback']) && function_exists($mapping['callback'])) {
+      if (isset($data) && isset($mapping['callback'])) {
         $callback = $mapping['callback'];
         $attributes['content'] = $callback($data);
       }
Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.628
diff -u -r1.628 theme.inc
--- includes/theme.inc	4 Feb 2011 19:03:14 -0000	1.628
+++ includes/theme.inc	12 Feb 2011 21:42:49 -0000
@@ -839,11 +839,9 @@
     foreach (array('preprocess functions', 'process functions') as $phase) {
       if (!empty($info[$phase])) {
         foreach ($info[$phase] as $processor_function) {
-          if (function_exists($processor_function)) {
-            // We don't want a poorly behaved process function changing $hook.
-            $hook_clone = $hook;
-            $processor_function($variables, $hook_clone);
-          }
+          // We don't want a poorly behaved process function changing $hook.
+          $hook_clone = $hook;
+          $processor_function($variables, $hook_clone);
         }
       }
     }
Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.1287
diff -u -r1.1287 common.inc
--- includes/common.inc	9 Feb 2011 02:23:52 -0000	1.1287
+++ includes/common.inc	12 Feb 2011 21:42:45 -0000
@@ -4314,10 +4314,8 @@
   // Libraries, Javascript and CSS have been added already, as they require
   // special handling.
   foreach ($elements['#attached'] as $callback => $options) {
-    if (function_exists($callback)) {
-      foreach ($elements['#attached'][$callback] as $args) {
-        call_user_func_array($callback, $args);
-      }
+    foreach ($elements['#attached'][$callback] as $args) {
+      call_user_func_array($callback, $args);
     }
   }
 
@@ -5585,9 +5583,7 @@
   // element is rendered into the final text.
   if (isset($elements['#pre_render'])) {
     foreach ($elements['#pre_render'] as $function) {
-      if (function_exists($function)) {
-        $elements = $function($elements);
-      }
+      $elements = $function($elements);
     }
   }
 
@@ -5631,9 +5627,7 @@
   // which allows the output'ed text to be filtered.
   if (isset($elements['#post_render'])) {
     foreach ($elements['#post_render'] as $function) {
-      if (function_exists($function)) {
-        $elements['#children'] = $function($elements['#children'], $elements);
-      }
+      $elements['#children'] = $function($elements['#children'], $elements);
     }
   }
 
@@ -7543,7 +7537,7 @@
     // Invoke the callback to get the URI. If there is no callback, set the
     // entity's 'uri' property to FALSE to indicate that it is known to not have
     // a URI.
-    if (isset($uri_callback) && function_exists($uri_callback)) {
+    if (isset($uri_callback)) {
       $entity->uri = $uri_callback($entity);
       if (!isset($entity->uri['options'])) {
         $entity->uri['options'] = array();
@@ -7577,7 +7571,7 @@
 function entity_label($entity_type, $entity) {
   $label = FALSE;
   $info = entity_get_info($entity_type);
-  if (isset($info['label callback']) && function_exists($info['label callback'])) {
+  if (isset($info['label callback'])) {
     $label = $info['label callback']($entity);
   }
   elseif (!empty($info['entity keys']['label']) && isset($entity->{$info['entity keys']['label']})) {
@@ -7800,16 +7794,14 @@
     $info = array();
     foreach (module_implements('filetransfer_info') as $module) {
       $function = $module . '_filetransfer_info';
-      if (function_exists($function)) {
-        $result = $function();
-        if (isset($result) && is_array($result)) {
-          foreach ($result as &$values) {
-            if (empty($values['file path'])) {
-              $values['file path'] = drupal_get_path('module', $module);
-            }
+      $result = $function();
+      if (isset($result) && is_array($result)) {
+        foreach ($result as &$values) {
+          if (empty($values['file path'])) {
+            $values['file path'] = drupal_get_path('module', $module);
           }
-          $info = array_merge_recursive($info, $result);
         }
+        $info = array_merge_recursive($info, $result);
       }
     }
     drupal_alter('filetransfer_info', $info);
Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.431
diff -u -r1.431 menu.inc
--- includes/menu.inc	4 Jan 2011 06:20:30 -0000	1.431
+++ includes/menu.inc	12 Feb 2011 21:42:48 -0000
@@ -616,7 +616,7 @@
     if ($callback == 'user_access') {
       $item['access'] = (count($arguments) == 1) ? user_access($arguments[0]) : user_access($arguments[0], $arguments[1]);
     }
-    elseif (function_exists($callback)) {
+    else {
       $item['access'] = call_user_func_array($callback, $arguments);
     }
   }
@@ -676,7 +676,7 @@
         $item['title'] = t($item['title'], menu_unserialize($item['title_arguments'], $map));
       }
     }
-    elseif ($callback && function_exists($callback)) {
+    elseif ($callback) {
       if (empty($item['title_arguments'])) {
         $item['title'] = $callback($item['title']);
       }
@@ -1672,7 +1672,7 @@
     // If this returns a valid theme, it will override any theme that was set
     // by a hook_custom_theme() implementation above.
     $router_item = menu_get_item();
-    if (!empty($router_item['access']) && !empty($router_item['theme_callback']) && function_exists($router_item['theme_callback'])) {
+    if (!empty($router_item['access']) && !empty($router_item['theme_callback'])) {
       $theme_name = call_user_func_array($router_item['theme_callback'], $router_item['theme_arguments']);
       if (drupal_theme_access($theme_name)) {
         $custom_theme = $theme_name;
Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.522
diff -u -r1.522 form.inc
--- includes/form.inc	29 Jan 2011 10:08:45 -0000	1.522
+++ includes/form.inc	12 Feb 2011 21:42:47 -0000
@@ -760,7 +760,7 @@
   // the actual form builder function ($callback) expects. This allows for
   // pre-populating a form with common elements for certain forms, such as
   // back/next/save buttons in multi-step form wizards. See drupal_build_form().
-  if (isset($form_state['wrapper_callback']) && function_exists($form_state['wrapper_callback'])) {
+  if (isset($form_state['wrapper_callback'])) {
     $form = call_user_func_array($form_state['wrapper_callback'], $args);
     // Put the prepopulated $form into $args.
     $args[0] = $form;
@@ -4275,9 +4275,7 @@
 
       // Redirect for processing.
       $function = $batch['redirect_callback'];
-      if (function_exists($function)) {
-        $function($batch['url'], array('query' => array('op' => 'start', 'id' => $batch['id'])));
-      }
+      $function($batch['url'], array('query' => array('op' => 'start', 'id' => $batch['id'])));
     }
     else {
       // Non-progressive execution: bypass the whole progressbar workflow
Index: includes/token.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/token.inc,v
retrieving revision 1.10
diff -u -r1.10 token.inc
--- includes/token.inc	18 Oct 2010 01:13:07 -0000	1.10
+++ includes/token.inc	12 Feb 2011 21:42:49 -0000
@@ -84,7 +84,7 @@
   }
 
   // Optionally alter the list of replacement values.
-  if (!empty($options['callback']) && function_exists($options['callback'])) {
+  if (!empty($options['callback'])) {
     $function = $options['callback'];
     $function($replacements, $data, $options);
   }
Index: modules/field/field.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/field.module,v
retrieving revision 1.94
diff -u -r1.94 field.module
--- modules/field/field.module	2 Jan 2011 17:26:39 -0000	1.94
+++ modules/field/field.module	12 Feb 2011 21:42:50 -0000
@@ -460,9 +460,7 @@
   $items = array();
   if (!empty($instance['default_value_function'])) {
     $function = $instance['default_value_function'];
-    if (function_exists($function)) {
-      $items = $function($entity_type, $entity, $field, $instance, $langcode);
-    }
+    $items = $function($entity_type, $entity, $field, $instance, $langcode);
   }
   elseif (!empty($instance['default_value'])) {
     $items = $instance['default_value'];
@@ -484,7 +482,6 @@
  */
 function _field_filter_items($field, $items) {
   $function = $field['module'] . '_field_is_empty';
-  function_exists($function);
   foreach ((array) $items as $delta => $item) {
     // Explicitly break if the function is undefined.
     if ($function($item, $field)) {
Index: modules/field_ui/field_ui.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field_ui/field_ui.module,v
retrieving revision 1.34
diff -u -r1.34 field_ui.module
--- modules/field_ui/field_ui.module	21 Nov 2010 07:28:39 -0000	1.34
+++ modules/field_ui/field_ui.module	12 Feb 2011 21:42:51 -0000
@@ -262,7 +262,7 @@
       if ($access_callback == 'user_access') {
         return (count($args) == 1) ? user_access($args[0]) : user_access($args[0], $args[1]);
       }
-      elseif (function_exists($access_callback)) {
+      else {
         return call_user_func_array($access_callback, $args);
       }
     }
Index: modules/field/modules/list/list.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/field/modules/list/list.module,v
retrieving revision 1.39
diff -u -r1.39 list.module
--- modules/field/modules/list/list.module	18 Dec 2010 00:50:03 -0000	1.39
+++ modules/field/modules/list/list.module	12 Feb 2011 21:42:51 -0000
@@ -232,7 +232,7 @@
 
   if (!isset($allowed_values[$field['id']])) {
     $function = $field['settings']['allowed_values_function'];
-    if (!empty($function) && function_exists($function)) {
+    if (!empty($function)) {
       $values = $function($field);
     }
     else {
Index: modules/search/search.pages.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/search/search.pages.inc,v
retrieving revision 1.25
diff -u -r1.25 search.pages.inc
--- modules/search/search.pages.inc	21 Nov 2010 20:36:36 -0000	1.25
+++ modules/search/search.pages.inc	12 Feb 2011 21:42:53 -0000
@@ -53,7 +53,7 @@
   // the search query URL clean as a whistle.
   if (empty($_POST['form_id']) || $_POST['form_id'] != 'search_form') {
     $conditions =  NULL;
-    if (isset($info['conditions_callback']) && function_exists($info['conditions_callback'])) {
+    if (isset($info['conditions_callback'])) {
       // Build an optional array of more search conditions.
       $conditions = call_user_func($info['conditions_callback'], $keys);
     }