diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 6b185ec1d912dc184973203d3068f5b60f3bed8b..9b22307443f5fb0eff1a61fc62398f74e38adacb 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -11,12 +11,13 @@ Features:
 - #505278 Panels 3 and multiple node type fields.
 - #495582 Reviewed Panels 3 integration (prep work for combo / multigroups).
   Implementation of fieldgroup_view_group() that can be used to render field groups.
+- #417122 by quicksketch: allow drupal_alter on field and widget settings.
 
 Bugfixes:
 - #482774 Update breaks when CCK is disabled.
 - #479994 by quicksketch: fix "add more' button with devel.module's query logging (multigroup).
 - #499696 by DeFr - Noderefernce / Userreference: fix Views mode when the view has exposed filters.
-- #498924 - #multiple FAPI attribute is used for a radios and checkboxes in content export forms.
+- #498924 #multiple FAPI attribute is used for a radios and checkboxes in content export forms.
 - #409144 Review extra elements for node edit form provided by core modules.
 - #361473 CCK fieldgroup panels doesn't respect CCK field privacy settings.
 - #515984 Multiple field delta ORDER BY incorrect.
diff --git a/content.install b/content.install
index 863e0e64f4dd43dd4d88552a36343b3422282864..9faaac4558006fefb57a18c9c80dc2db241aaa5a 100644
--- a/content.install
+++ b/content.install
@@ -69,7 +69,7 @@ function content_types_install() {
     if (!empty($field['module']) && !empty($field['widget_module'])) {
       $field['widget_settings'] = unserialize($field['widget_settings']);
       $field['display_settings'] = unserialize($field['display_settings']);
-      $field['columns'] = module_invoke($field['module'], 'field_settings', 'database columns', $field);
+      $field['columns'] = (array) module_invoke($field['module'], 'field_settings', 'database columns', $field);
       $field = content_field_instance_expand($field);
       $fields[$field['type_name']][$field['field_name']] = $field;
     }
diff --git a/content.module b/content.module
index 4d3428eeeeb5807524e3be3c81dc496ac106d806..7ae3adccd2dfb848b21060596a4d73082f42ed24 100644
--- a/content.module
+++ b/content.module
@@ -631,7 +631,7 @@ function content_associate_fields($module) {
   foreach ($types as $type_name => $fields) {
     foreach ($fields as $field) {
       if ($field['module'] == $module && !in_array($field['field_name'], $fields_set)) {
-        $columns = module_invoke($field['module'], 'field_settings', 'database columns', $field);
+        $columns = (array) module_invoke($field['module'], 'field_settings', 'database columns', $field);
         db_query("UPDATE {". content_field_tablename() ."} SET db_columns = '%s' WHERE field_name = '%s'", serialize($columns), $field['field_name']);
         $fields_set[] = $field['field_name'];
       }
diff --git a/includes/content.admin.inc b/includes/content.admin.inc
index 280bf464a12ad6536cd9698e2049ce9bb43ff584..93ef4cd13d1b07306408b57b4be4535a7c7c6504 100644
--- a/includes/content.admin.inc
+++ b/includes/content.admin.inc
@@ -1029,10 +1029,11 @@ function content_field_edit_form(&$form_state, $type_name, $field_name) {
     '#type' => 'hidden',
     '#default_value' => $field['widget']['weight'],
   );
-  $additions = module_invoke($widget_type['module'], 'widget_settings', 'form', $field['widget']);
-  if (is_array($additions)) {
-    $form['widget'] = array_merge($form['widget'], $additions);
-  }
+
+  $additions = (array) module_invoke($widget_type['module'], 'widget_settings', 'form', $field['widget']);
+  drupal_alter('widget_settings', $additions, 'form', $field['widget']);
+  $form['widget'] = array_merge($form['widget'], $additions);
+
   $form['widget']['description'] = array(
     '#type' => 'textarea',
     '#title' => t('Help text'),
@@ -1148,10 +1149,9 @@ function content_field_edit_form(&$form_state, $type_name, $field_name) {
     '#value' => serialize($field),
   );
 
-  $additions = module_invoke($field_type['module'], 'field_settings', 'form', $field);
-  if (is_array($additions)) {
-    $form['field'] = array_merge($form['field'], $additions);
-  }
+  $additions = (array) module_invoke($field_type['module'], 'field_settings', 'form', $field);
+  drupal_alter('field_settings', $additions, 'form', $field);
+  $form['field'] = array_merge($form['field'], $additions);
 
   $form['submit'] = array(
     '#type' => 'submit',
diff --git a/includes/content.crud.inc b/includes/content.crud.inc
index 63b18ec877723de6f5ae2452f13555594dc6b15b..2942940eaf6628d6f5dee33baa0e6d9bb4959257 100644
--- a/includes/content.crud.inc
+++ b/includes/content.crud.inc
@@ -42,9 +42,9 @@ function content_field_default_values($field_type) {
     $field['active'] = 1;
   }
 
-  $field['columns'] = module_invoke($module, 'field_settings', 'database columns', $field);
+  $field['columns'] = (array) module_invoke($module, 'field_settings', 'database columns', $field);
   // Ensure columns always default to NULL values.
-  foreach ((array) $field['columns'] as $column_name => $column) {
+  foreach ($field['columns'] as $column_name => $column) {
     $field['columns'][$column_name]['not null'] = FALSE;
   }
 
@@ -53,11 +53,10 @@ function content_field_default_values($field_type) {
   $field['db_storage'] = CONTENT_DB_STORAGE_PER_CONTENT_TYPE;
 
   // Make sure field settings all have an index in the array.
-  $setting_names = module_invoke($module, 'field_settings', 'save', $field);
-  if (is_array($setting_names)) {
-    foreach ($setting_names as $setting) {
-      $field[$setting] = NULL;
-    }
+  $setting_names = (array) module_invoke($module, 'field_settings', 'save', $field);
+  drupal_alter('field_settings', $setting_names, 'save', $field);
+  foreach ($setting_names as $setting) {
+    $field[$setting] = NULL;
   }
   return $field;
 }
@@ -93,9 +92,10 @@ function content_instance_default_values($field_name, $type_name, $widget_type)
   }
 
   // Make sure widget settings all have an index in the array.
-  $settings_names = module_invoke($module, 'widget_settings', 'save', $widget);
+  $settings_names = (array) module_invoke($module, 'widget_settings', 'save', $widget);
+  drupal_alter('widget_settings', $settings_names, 'save', $widget);
   $widget['widget_settings'] = array();
-  foreach ((array) $settings_names as $name) {
+  foreach ($settings_names as $name) {
     $widget['widget_settings'][$name] = NULL;
   }
   return $widget;
@@ -399,14 +399,14 @@ function content_field_instance_update($field, $rebuild = TRUE) {
 function _content_field_write($field, $op = 'update') {
   // Rearrange the data to create the global_settings array.
   $field['global_settings'] = array();
-  $setting_names = module_invoke($field['module'], 'field_settings', 'save', $field);
-  if (is_array($setting_names)) {
-    foreach ($setting_names as $setting) {
-      // Unlike _content_field_instance_write() and 'widget_settings', 'global_settings'
-      // is never preexisting, so we take no particular precautions here.
-      $field['global_settings'][$setting] = isset($field[$setting]) ? $field[$setting] : '';
-      unset($field[$setting]);
-    }
+  $setting_names = (array) module_invoke($field['module'], 'field_settings', 'save', $field);
+  drupal_alter('field_settings', $setting_names, 'save', $field);
+
+  foreach ($setting_names as $setting) {
+    // Unlike _content_field_instance_write() and 'widget_settings', 'global_settings'
+    // is never preexisting, so we take no particular precautions here.
+    $field['global_settings'][$setting] = isset($field[$setting]) ? $field[$setting] : '';
+    unset($field[$setting]);
   }
   // 'columns' is a reserved word in MySQL4, so our column is named 'db_columns'.
   $field['db_columns'] = $field['columns'];
@@ -435,16 +435,15 @@ function _content_field_instance_write($field, $op = 'update') {
   $field = content_field_instance_collapse($field);
 
   // Rearrange the data to create the widget_settings array.
-  $setting_names = module_invoke($field['widget_module'], 'widget_settings', 'save', $field);
-  if (is_array($setting_names)) {
-    foreach ($setting_names as $setting) {
-      // In some cases (when the updated $field was originally read from
-      // the db, as opposed to gathered from the values of a form), the values
-      // are already in the right place, we take care to not wipe them.
-      if (isset($field[$setting])) {
-        $field['widget_settings'][$setting] = $field[$setting];
-        unset($field[$setting]);
-      }
+  $setting_names = (array) module_invoke($field['widget_module'], 'widget_settings', 'save', $field);
+  drupal_alter('widget_settings', $setting_names, 'save', $field);
+  foreach ($setting_names as $setting) {
+    // In some cases (when the updated $field was originally read from
+    // the db, as opposed to gathered from the values of a form), the values
+    // are already in the right place, we take care to not wipe them.
+    if (isset($field[$setting])) {
+      $field['widget_settings'][$setting] = $field[$setting];
+      unset($field[$setting]);
     }
   }
 
diff --git a/includes/views/content.views.inc b/includes/views/content.views.inc
index eecea7b893cf07545c323a6e20980941dcb966c4..684d1b6ac34410118d3c2750b19b9f8da11a5a37 100644
--- a/includes/views/content.views.inc
+++ b/includes/views/content.views.inc
@@ -140,7 +140,8 @@ function content_views_data() {
   $data = array();
   foreach (content_fields() as $field) {
     $module = $field['module'];
-    $result = module_invoke($module, 'field_settings', 'views data', $field);
+    $result = (array) module_invoke($module, 'field_settings', 'views data', $field);
+    drupal_alter('field_settings', $result, 'views data', $field);
     if (empty($result)) {
       $result = content_views_field_views_data($field);
     }
diff --git a/includes/views/content.views_convert.inc b/includes/views/content.views_convert.inc
index b83119d093881101e0723385b149bdd01173c494..aaa94f90c11b24e4e4d460d52832db54f45714e3 100644
--- a/includes/views/content.views_convert.inc
+++ b/includes/views/content.views_convert.inc
@@ -22,7 +22,8 @@ function content_views_convert($display, $type, &$view, $views_field) {
     foreach ($types as $ctype) {
       foreach ($ctype['fields'] as $field) {
         $module = $field['module'];
-        $result = module_invoke($module, 'field_settings', 'views data', $field);
+        $result = (array) module_invoke($module, 'field_settings', 'views data', $field);
+        drupal_alter('field_settings', $result, 'views data', $field);
         if (empty($result)) {
           // The views field name had the column name appended,
           // like field_name_value or field_username_uid.