Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.493
diff -u -p -r1.493 form.inc
--- includes/form.inc	16 Sep 2010 20:14:49 -0000	1.493
+++ includes/form.inc	18 Sep 2010 04:44:57 -0000
@@ -1142,6 +1142,25 @@ function _form_validate(&$elements, &$fo
             }
           }
         }
+        // Non-multiple select fields always have a value in HTML. If the user
+        // does not change the form, it will be the value of the first option.
+        // Because of this, form validation for the field will almost always
+        // pass, even if the user did not select anything. To work around this
+        // browser behavior, select fields without a #default_value get an
+        // additional, first "Please select" option by default, which is an
+        // empty string. Thus, in case the submitted value is an empty string,
+        // we reset the element's value to NULL to trigger the regular #required
+        // handling below.
+        // @see form_process_select()
+        // @see form_select_options()
+        elseif ($elements['#type'] == 'select' && !$elements['#multiple'] && !isset($elements['#default_value']) && $elements['#value'] === $elements['#empty_value']) {
+          if (!isset($elements['#required']) || $elements['#required']) {
+            $elements['#value'] = NULL;
+          }
+          else {
+            $elements['#value'] = $elements['#empty_value'];
+          }
+        }
         elseif (!isset($options[$elements['#value']])) {
           form_error($elements, $t('An illegal choice has been detected. Please contact the site administrator.'));
           watchdog('form', 'Illegal choice %choice in %name element.', array('%choice' => $elements['#value'], '%name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
@@ -1188,8 +1207,18 @@ function _form_validate(&$elements, &$fo
     // length if it's a string, and the item count if it's an array.
     // An unchecked checkbox has a #value of integer 0, different than string
     // '0', which could be a valid value.
-    if (isset($elements['#needs_validation']) && $elements['#required'] && (!count($elements['#value']) || (is_string($elements['#value']) && strlen(trim($elements['#value'])) == 0) || $elements['#value'] === 0)) {
-      form_error($elements, $t('!name field is required.', array('!name' => $elements['#title'])));
+    if (isset($elements['#needs_validation']) && !empty($elements['#required']) && (!count($elements['#value']) || (is_string($elements['#value']) && strlen(trim($elements['#value'])) == 0) || $elements['#value'] === 0)) {
+      // Although unusual and actually discouraged, a #title is not mandatory
+      // for form elements. In case the element does not have a title, we cannot
+      // set a form error message. Note that instead of setting no #title, form
+      // constructors are encouraged to set #title_display to 'hidden' instead
+      // to improve accessibility.
+      if (isset($elements['#title'])) {
+        form_error($elements, $t('!name field is required.', array('!name' => $elements['#title'])));
+      }
+      else {
+        form_error($elements);
+      }
     }
 
     // Call user-defined form level validators.
@@ -1540,7 +1569,6 @@ function form_builder($form_id, $element
   }
   // Assign basic defaults common for all form elements.
   $element += array(
-    '#required' => FALSE,
     '#attributes' => array(),
     '#title_display' => 'before',
   );
@@ -1799,7 +1827,7 @@ function _form_builder_handle_input_elem
         }
       }
       // Mark all posted values for validation.
-      if (isset($element['#value']) || (!empty($element['#required']))) {
+      if (isset($element['#value']) || !empty($element['#required'])) {
         $element['#needs_validation'] = TRUE;
       }
     }
@@ -2238,6 +2266,75 @@ function _form_options_flatten($array) {
 }
 
 /**
+ * Processes a select list form element.
+ *
+ * This process callback is mandatory for select fields, since all user agents
+ * automatically preselect the first available option of single (non-multiple)
+ * select lists.
+ *
+ * @param $element
+ *   The form element to process. Properties used:
+ *   - #multiple: (optional) Indicates whether one or more options can be
+ *     selected. Defaults to FALSE.
+ *   - #default_value: Must be NULL or not set in case there is no value for the
+ *     element yet, in which case a first default option is inserted by default.
+ *     Whether this first option is a valid option depends on whether the field
+ *     is #required or not.
+ *   - #required: (optional) Whether the user needs to select an option (TRUE)
+ *     or not (FALSE). Defaults to TRUE.
+ *   - #empty_option: (optional) The label to show for the first default option.
+ *     By default, the label is automatically set to "- Please select -" for a
+ *     required field and "- None -" for an optional field.
+ *   - #empty_value: (optional) The value for the first default option, which is
+ *     used to determine whether the user submitted a value or not. Defaults to
+ *     '' (an empty string). To be used in case the field is optional and the
+ *     empty default value should have a special value (e.g., a constant).
+ *
+ * @see _form_validate()
+ */
+function form_process_select($element) {
+  // #multiple select fields need a special #name.
+  if ($element['#multiple']) {
+    $element['#attributes']['multiple'] = 'multiple';
+    $element['#attributes']['name'] = $element['#name'] . '[]';
+  }
+  // A non-#multiple select needs special handling to prevent user agents from
+  // preselecting the first option without intention.
+  else {
+    // Unless there is a #default_value already, the user has to select a value
+    // for #required select fields. By default, all select fields are treated
+    // as if #required was TRUE.
+    if (!isset($element['#default_value']) && (!isset($element['#required']) || $element['#required'])) {
+      $element['#required'] = TRUE;
+      $element += array(
+        '#empty_value' => '',
+        '#empty_option' => t('- Please select -'),
+      );
+      $add_empty_option = TRUE;
+    }
+    // If #required is FALSE, the user may optionally choose a value. The empty
+    // default option is always contained and always available.
+    elseif (isset($element['#required']) && !$element['#required']) {
+      $element['#required'] = FALSE;
+      $element += array(
+        '#empty_value' => '',
+        '#empty_option' => t('- None -'),
+      );
+      $add_empty_option = TRUE;
+    }
+    // If one of the above conditions is met, add a first empty default option,
+    // which is always invalid for #required and not #multiple select lists that
+    // do not specify a #default_value (ensured through special handling in
+    // _form_validate()). A #multiple select list does not get this option,
+    // since it would not make sense, user interface-wise.
+    if (isset($add_empty_option)) {
+      $element['#options'] = array($element['#empty_value'] => $element['#empty_option']) + $element['#options'];
+    }
+  }
+  return $element;
+}
+
+/**
  * Returns HTML for a select form element.
  *
  * It is possible to group options together; to do this, change the format of
@@ -2254,14 +2351,9 @@ function _form_options_flatten($array) {
  */
 function theme_select($variables) {
   $element = $variables['element'];
-  element_set_attributes($element, array('id', 'name', 'size'));
+  element_set_attributes($element, array('id', 'size'));
   _form_set_class($element, array('form-select'));
 
-  if (!empty($element['#multiple'])) {
-    $element['#attributes']['multiple'] = 'multiple';
-    $element['#attributes']['name'] .= '[]';
-  }
-
   return '<select' . drupal_attributes($element['#attributes']) . '>' . form_select_options($element) . '</select>';
 }
 
@@ -2449,14 +2541,14 @@ function form_process_password_confirm($
     '#type' => 'password',
     '#title' => t('Password'),
     '#value' => empty($element['#value']) ? NULL : $element['#value']['pass1'],
-    '#required' => $element['#required'],
+    '#required' => !empty($element['#required']),
     '#attributes' => array('class' => array('password-field')),
   );
   $element['pass2'] =  array(
     '#type' => 'password',
     '#title' => t('Confirm password'),
     '#value' => empty($element['#value']) ? NULL : $element['#value']['pass2'],
-    '#required' => $element['#required'],
+    '#required' => !empty($element['#required']),
     '#attributes' => array('class' => array('password-confirm')),
   );
   $element['#element_validate'] = array('password_confirm_validate');
@@ -2480,7 +2572,7 @@ function password_confirm_validate($elem
       form_error($element, t('The specified passwords do not match.'));
     }
   }
-  elseif ($element['#required'] && !empty($element_state['input'])) {
+  elseif (!empty($element['#required']) && !empty($element_state['input'])) {
     form_error($element, t('Password field is required.'));
   }
 
Index: includes/install.core.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/install.core.inc,v
retrieving revision 1.30
diff -u -p -r1.30 install.core.inc
--- includes/install.core.inc	14 Sep 2010 21:42:05 -0000	1.30
+++ includes/install.core.inc	18 Sep 2010 03:44:31 -0000
@@ -1715,11 +1715,10 @@ function _install_configure_form($form, 
   );
 
   $countries = country_get_list();
-  $countries = array_merge(array('' => st('No default country')), $countries);
   $form['server_settings']['site_default_country'] = array(
     '#type' => 'select',
     '#title' => t('Default country'),
-    '#default_value' => variable_get('site_default_country', ''),
+    '#default_value' => variable_get('site_default_country', NULL),
     '#options' => $countries,
     '#description' => st('Select the default country for the site.'),
     '#weight' => 0,
Index: modules/aggregator/aggregator.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/aggregator/aggregator.admin.inc,v
retrieving revision 1.54
diff -u -p -r1.54 aggregator.admin.inc
--- modules/aggregator/aggregator.admin.inc	26 Jun 2010 19:55:47 -0000	1.54
+++ modules/aggregator/aggregator.admin.inc	18 Sep 2010 03:45:35 -0000
@@ -254,10 +254,13 @@ function aggregator_form_opml($form, &$f
     '#options' => $period,
     '#description' => t('The length of time between feed updates. Requires a correctly configured <a href="@cron">cron maintenance task</a>.', array('@cron' => url('admin/reports/status'))),
   );
-  $form['block'] = array('#type' => 'select',
+  $form['block'] = array(
+    '#type' => 'select',
     '#title' => t('News items in block'),
+    '#required' => FALSE,
     '#default_value' => 5,
-    '#options' => drupal_map_assoc(array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)),
+    '#empty_value' => 0,
+    '#options' => drupal_map_assoc(array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)),
     '#description' => t("Drupal can make a block with the most recent news items of a feed. You can <a href=\"@block-admin\">configure blocks</a> to be displayed in the sidebar of your page. This setting lets you configure the number of news items to show in a feed's block. If you choose '0' these feeds' blocks will be disabled.", array('@block-admin' => url('admin/structure/block'))),
   );
 
Index: modules/aggregator/aggregator.processor.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/aggregator/aggregator.processor.inc,v
retrieving revision 1.12
diff -u -p -r1.12 aggregator.processor.inc
--- modules/aggregator/aggregator.processor.inc	4 Dec 2009 16:49:45 -0000	1.12
+++ modules/aggregator/aggregator.processor.inc	18 Sep 2010 03:47:44 -0000
@@ -70,7 +70,7 @@ function aggregator_aggregator_remove($f
 function aggregator_form_aggregator_admin_form_alter(&$form, $form_state) {
   if (in_array('aggregator', variable_get('aggregator_processors', array('aggregator')))) {
     $info = module_invoke('aggregator', 'aggregator_process', 'info');
-    $items = array(0 => t('none')) + drupal_map_assoc(array(3, 5, 10, 15, 20, 25), '_aggregator_items');
+    $items = drupal_map_assoc(array(3, 5, 10, 15, 20, 25), '_aggregator_items');
     $period = drupal_map_assoc(array(3600, 10800, 21600, 32400, 43200, 86400, 172800, 259200, 604800, 1209600, 2419200, 4838400, 9676800), 'format_interval');
     $period[AGGREGATOR_CLEAR_NEVER] = t('Never');
 
@@ -90,8 +90,10 @@ function aggregator_form_aggregator_admi
 
     $form['modules']['aggregator']['aggregator_summary_items'] = array(
       '#type' => 'select',
-      '#title' => t('Number of items shown in listing pages') ,
+      '#title' => t('Number of items shown in listing pages'),
+      '#required' => FALSE,
       '#default_value' => variable_get('aggregator_summary_items', 3),
+      '#empty_value' => 0,
       '#options' => $items,
     );
 
Index: modules/block/block.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/block/block.admin.inc,v
retrieving revision 1.87
diff -u -p -r1.87 block.admin.inc
--- modules/block/block.admin.inc	17 Sep 2010 13:32:56 -0000	1.87
+++ modules/block/block.admin.inc	18 Sep 2010 03:29:19 -0000
@@ -85,9 +85,6 @@ function block_admin_display_form($form,
     $block_regions = system_region_list($theme, REGIONS_VISIBLE);
   }
 
-  // We always add a region for disabled blocks.
-  $block_regions += array(BLOCK_REGION_NONE => '<' . t('none') . '>');
-
   // Weights range from -delta to +delta, so delta should be at least half
   // of the amount of blocks present. This makes sure all blocks in the same
   // region get an unique weight.
@@ -100,7 +97,8 @@ function block_admin_display_form($form,
   );
   $form['block_regions'] = array(
     '#type' => 'value',
-    '#value' => $block_regions,
+    // Add a last region for disabled blocks.
+    '#value' => $block_regions + array(BLOCK_REGION_NONE => BLOCK_REGION_NONE),
   );
   $form['blocks'] = array();
   $form['#tree'] = TRUE;
@@ -127,13 +125,15 @@ function block_admin_display_form($form,
       '#default_value' => $block['weight'],
       '#delta' => $weight_delta,
       '#title_display' => 'invisible',
-      '#title' => t('Weight for @block block', array('%block' => $block['info'])),
+      '#title' => t('Weight for @block block', array('@block' => $block['info'])),
     );
     $form['blocks'][$key]['region'] = array(
       '#type' => 'select',
-      '#default_value' => $block['region'],
+      '#required' => FALSE,
+      '#default_value' => $block['region'] != BLOCK_REGION_NONE ? $block['region'] : NULL,
+      '#empty_value' => BLOCK_REGION_NONE,
       '#title_display' => 'invisible',
-      '#title' => t('Region for @block block', array('%block' => $block['info'])),
+      '#title' => t('Region for @block block', array('@block' => $block['info'])),
       '#options' => $block_regions,
     );
     $form['blocks'][$key]['configure'] = array(
@@ -150,7 +150,7 @@ function block_admin_display_form($form,
     }
   }
   // Do not allow disabling the main system content block.
-  unset($form['blocks']['system_main']['region']['#options'][BLOCK_REGION_NONE]);
+  $form['blocks']['system_main']['region']['#required'] = TRUE;
 
   $form['actions'] = array(
     '#tree' => FALSE,
@@ -302,9 +302,10 @@ function block_admin_configure($form, &$
       $form['regions'][$key] = array(
         '#type' => 'select',
         '#title' => $theme->info['name'],
-        '#default_value' => (!empty($region) ? $region : BLOCK_REGION_NONE),
-        '#options' => array(BLOCK_REGION_NONE => t('<none>')) + system_region_list($key, REGIONS_VISIBLE),
-        '#expandable' => ($key !== $theme_default),
+        '#required' => FALSE,
+        '#default_value' => !empty($region) && $region != -1 ? $region : NULL,
+        '#empty_value' => BLOCK_REGION_NONE,
+        '#options' => system_region_list($key, REGIONS_VISIBLE),
         '#weight' => ($key == $theme_default ? 9 : 10),
       );
     }
@@ -657,7 +658,12 @@ function template_preprocess_block_admin
     $block = &$variables['form']['blocks'][$i];
 
     // Fetch the region for the current block.
-    $region = $block['region']['#default_value'];
+    if (isset($block['region']['#default_value'])) {
+      $region = $block['region']['#default_value'];
+    }
+    else {
+      $region = BLOCK_REGION_NONE;
+    }
 
     // Set special classes needed for table drag and drop.
     $block['region']['#attributes']['class'] = array('block-region-select', 'block-region-' . $region);
Index: modules/image/image.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/image/image.admin.inc,v
retrieving revision 1.21
diff -u -p -r1.21 image.admin.inc
--- modules/image/image.admin.inc	30 Jul 2010 02:47:28 -0000	1.21
+++ modules/image/image.admin.inc	18 Sep 2010 03:59:28 -0000
@@ -116,7 +116,7 @@ function image_style_form($form, &$form_
   }
 
   // Build the new image effect addition form and add it to the effect list.
-  $new_effect_options = array('' => t('Select a new effect'));
+  $new_effect_options = array();
   foreach (image_effect_definitions() as $effect => $definition) {
     $new_effect_options[$effect] = check_plain($definition['label']);
   }
@@ -291,11 +291,12 @@ function image_style_delete_form($form, 
   $form_state['image_style'] = $style;
 
   $replacement_styles = array_diff_key(image_style_options(), array($style['name'] => ''));
-  $replacement_styles[''] = t('No replacement, just delete');
   $form['replacement'] = array(
     '#title' => t('Replacement style'),
     '#type' => 'select',
+    '#required' => FALSE,
     '#options' => $replacement_styles,
+    '#empty_option' => t('No replacement, just delete'),
   );
 
   return confirm_form(
Index: modules/image/image.field.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/image/image.field.inc,v
retrieving revision 1.27
diff -u -p -r1.27 image.field.inc
--- modules/image/image.field.inc	9 Sep 2010 23:28:16 -0000	1.27
+++ modules/image/image.field.inc	18 Sep 2010 04:05:40 -0000
@@ -269,8 +269,10 @@ function image_field_widget_settings_for
   $form['preview_image_style'] = array(
     '#title' => t('Preview image style'),
     '#type' => 'select',
-    '#options' => array('' => '<' . t('no preview') . '>') + image_style_options(FALSE),
+    '#required' => FALSE,
+    '#options' => image_style_options(FALSE),
     '#default_value' => $settings['preview_image_style'],
+    '#empty_option' => t('- No preview -'),
     '#description' => t('The preview image will be shown while editing the content.'),
     '#weight' => 15,
   );
@@ -418,22 +420,24 @@ function image_field_formatter_settings_
   $display = $instance['display'][$view_mode];
   $settings = $display['settings'];
 
-  $image_styles = array('' => t('None (original image)')) + image_style_options(FALSE);
+  $image_styles = image_style_options(FALSE);
   $form['image_style'] = array(
     '#title' => t('Image style'),
     '#type' => 'select',
+    '#required' => FALSE,
     '#default_value' => $settings['image_style'],
+    '#empty_option' => t('None (original image)'),
     '#options' => $image_styles,
   );
 
   $link_types = array(
-    '' => t('<none>'),
     'content' => t('Content'),
     'file' => t('File'),
   );
   $form['image_link'] = array(
     '#title' => t('Link image to'),
     '#type' => 'select',
+    '#required' => FALSE,
     '#default_value' => $settings['image_link'],
     '#options' => $link_types,
   );
Index: modules/locale/locale.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/locale/locale.admin.inc,v
retrieving revision 1.17
diff -u -p -r1.17 locale.admin.inc
--- modules/locale/locale.admin.inc	30 Jul 2010 02:47:28 -0000	1.17
+++ modules/locale/locale.admin.inc	18 Sep 2010 04:32:56 -0000
@@ -854,7 +854,8 @@ function locale_translation_filter_form(
       $form['filters']['status'][$key] = array(
         '#title' => $filter['title'],
         '#type' => 'select',
-        '#multiple' => FALSE,
+        '#required' => FALSE,
+        '#default_value' => key($filter['options']),
         '#size' => 0,
         '#options' => $filter['options'],
       );
Index: modules/menu/menu.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/menu/menu.admin.inc,v
retrieving revision 1.84
diff -u -p -r1.84 menu.admin.inc
--- modules/menu/menu.admin.inc	7 Sep 2010 22:12:05 -0000	1.84
+++ modules/menu/menu.admin.inc	18 Sep 2010 04:11:00 -0000
@@ -680,22 +680,22 @@ function menu_configure() {
   $menu_options = menu_get_menus();
 
   $main = variable_get('menu_main_links_source', 'main-menu');
-  $main_options = array_merge($menu_options, array('' => t('No Main links')));
   $form['menu_main_links_source'] = array(
     '#type' => 'select',
     '#title' => t('Source for the Main links'),
+    '#required' => FALSE,
     '#default_value' => variable_get('menu_main_links_source', 'main-menu'),
-    '#options' => $main_options,
+    '#options' => $menu_options,
     '#tree' => FALSE,
     '#description' => t('Select what should be displayed as the Main links (typically at the top of the page).'),
   );
 
-  $secondary_options = array_merge($menu_options, array('' => t('No Secondary links')));
   $form['menu_secondary_links_source'] = array(
     '#type' => 'select',
     '#title' => t('Source for the Secondary links'),
+    '#required' => FALSE,
     '#default_value' => variable_get('menu_secondary_links_source', 'user-menu'),
-    '#options' => $secondary_options,
+    '#options' => $menu_options,
     '#tree' => FALSE,
     '#description' => t("Select the source for the Secondary links. An advanced option allows you to use the same source for both Main links (currently %main) and Secondary links: if your source menu has two levels of hierarchy, the top level menu links will appear in the Main links, and the children of the active link will appear in the Secondary links." , array('%main' => $main_options[$main])),
   );
Index: modules/simpletest/tests/ajax_forms_test.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/ajax_forms_test.module,v
retrieving revision 1.7
diff -u -p -r1.7 ajax_forms_test.module
--- modules/simpletest/tests/ajax_forms_test.module	6 May 2010 05:59:31 -0000	1.7
+++ modules/simpletest/tests/ajax_forms_test.module	18 Sep 2010 01:55:45 -0000
@@ -38,7 +38,6 @@ function ajax_forms_test_menu() {
  * A basic form used to test form_state['values'] during callback.
  */
 function ajax_forms_test_simple_form($form, &$form_state) {
-  $form = array();
   $form['select'] = array(
     '#type' => 'select',
     '#options' => array(
Index: modules/system/system.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.module,v
retrieving revision 1.961
diff -u -p -r1.961 system.module
--- modules/system/system.module	17 Sep 2010 14:53:21 -0000	1.961
+++ modules/system/system.module	18 Sep 2010 01:55:45 -0000
@@ -401,7 +401,7 @@ function system_element_info() {
     '#input' => TRUE,
     '#size' => 0,
     '#multiple' => FALSE,
-    '#process' => array('ajax_process_form'),
+    '#process' => array('form_process_select', 'ajax_process_form'),
     '#theme' => 'select',
     '#theme_wrappers' => array('form_element'),
   );