Issue #2131851 by tim.plunkett: Form errors must be specific to a form and not a global.

core/includes/authorize.inc

@@ -210,7 +210,7 @@ function authorize_filetransfer_form_validate($form, &$form_state) {
     catch (Exception $e) {
       // The format of this error message is similar to that used on the
       // database connection form in the installer.
-      form_set_error('connection_settings', t('Failed to connect to the server. The server reports the following message: !message For more help installing or updating code on your server, see the <a href="@handbook_url">handbook</a>.', array(
+      form_set_error('connection_settings', $form_state, t('Failed to connect to the server. The server reports the following message: !message For more help installing or updating code on your server, see the <a href="@handbook_url">handbook</a>.', array(
         '!message' => '<p class="error">' . $e->getMessage()  . '</p>',
         '@handbook_url' => 'http://drupal.org/documentation/install/modules-themes',
       )));

core/includes/form.inc

@@ -274,8 +274,8 @@ function form_execute_handlers($type, &$form, &$form_state) {
  *
  * @deprecated as of Drupal 8.0. Use \Drupal::formBuilder()->setErrorByName()
  */
-function form_set_error($name = NULL, $message = '', $limit_validation_errors = NULL) {
-  return \Drupal::formBuilder()->setErrorByName($name, $message, $limit_validation_errors);
+function form_set_error($name, array &$form_state, $message = '') {
+  \Drupal::formBuilder()->setErrorByName($name, $form_state, $message);
 }
 
 /**
@@ -283,8 +283,8 @@ function form_set_error($name = NULL, $message = '', $limit_validation_errors =
  *
  * @deprecated as of Drupal 8.0. Use \Drupal::formBuilder()->clearErrors()
  */
-function form_clear_error() {
-  \Drupal::formBuilder()->clearErrors();
+function form_clear_error(array &$form_state) {
+  \Drupal::formBuilder()->clearErrors($form_state);
 }
 
 /**
@@ -292,8 +292,8 @@ function form_clear_error() {
  *
  * @deprecated as of Drupal 8.0. Use \Drupal::formBuilder()->getErrors()
  */
-function form_get_errors() {
-  return \Drupal::formBuilder()->getErrors();
+function form_get_errors(array &$form_state) {
+  return \Drupal::formBuilder()->getErrors($form_state);
 }
 
 /**
@@ -301,8 +301,8 @@ function form_get_errors() {
  *
  * @deprecated as of Drupal 8.0. Use \Drupal::formBuilder()->getError()
  */
-function form_get_error($element) {
-  return \Drupal::formBuilder()->getError($element);
+function form_get_error($element, array &$form_state) {
+  return \Drupal::formBuilder()->getError($element, $form_state);
 }
 
 /**
@@ -310,8 +310,8 @@ function form_get_error($element) {
  *
  * @deprecated as of Drupal 8.0. Use \Drupal::formBuilder()->setError()
  */
-function form_error(&$element, $message = '') {
-  \Drupal::formBuilder()->setError($element, $message);
+function form_error(&$element, array &$form_state, $message = '') {
+  \Drupal::formBuilder()->setError($element, $form_state, $message);
 }
 
 /**
@@ -1108,11 +1108,11 @@ function password_confirm_validate($element, &$element_state) {
   $pass2 = trim($element['pass2']['#value']);
   if (!empty($pass1) || !empty($pass2)) {
     if (strcmp($pass1, $pass2)) {
-      form_error($element, t('The specified passwords do not match.'));
+      form_error($element, $element_state, t('The specified passwords do not match.'));
     }
   }
   elseif ($element['#required'] && !empty($element_state['input'])) {
-    form_error($element, t('Password field is required.'));
+    form_error($element, $element_state, t('Password field is required.'));
   }
 
   // Password field must be converted from a two-element array into a single
@@ -1457,7 +1457,7 @@ function form_validate_pattern($element, &$form_state) {
     $pattern = '{^(?:' . $element['#pattern'] . ')$}';
 
     if (!preg_match($pattern, $element['#value'])) {
-      form_error($element, t('%name field is not in the right format.', array('%name' => $element['#title'])));
+      form_error($element, $form_state, t('%name field is not in the right format.', array('%name' => $element['#title'])));
     }
   }
 }
@@ -1767,11 +1767,11 @@ function form_validate_table($element, &$form_state) {
   }
   if ($element['#multiple']) {
     if (!is_array($element['#value']) || !count(array_filter($element['#value']))) {
-      form_error($element, t('No items selected.'));
+      form_error($element, $form_state, t('No items selected.'));
     }
   }
   elseif (!isset($element['#value']) || $element['#value'] === '') {
-    form_error($element, t('No item selected.'));
+    form_error($element, $form_state, t('No item selected.'));
   }
 }
 
@@ -1894,7 +1894,7 @@ function form_process_machine_name($element, &$form_state) {
 function form_validate_machine_name(&$element, &$form_state) {
   // Verify that the machine name not only consists of replacement tokens.
   if (preg_match('@^' . $element['#machine_name']['replace'] . '+$@', $element['#value'])) {
-    form_error($element, t('The machine-readable name must contain unique characters.'));
+    form_error($element, $form_state, t('The machine-readable name must contain unique characters.'));
   }
 
   // Verify that the machine name contains no disallowed characters.
@@ -1903,15 +1903,15 @@ function form_validate_machine_name(&$element, &$form_state) {
       // Since a hyphen is the most common alternative replacement character,
       // a corresponding validation error message is supported here.
       if ($element['#machine_name']['replace'] == '-') {
-        form_error($element, t('The machine-readable name must contain only lowercase letters, numbers, and hyphens.'));
+        form_error($element, $form_state, t('The machine-readable name must contain only lowercase letters, numbers, and hyphens.'));
       }
       // Otherwise, we assume the default (underscore).
       else {
-        form_error($element, t('The machine-readable name must contain only lowercase letters, numbers, and underscores.'));
+        form_error($element, $form_state, t('The machine-readable name must contain only lowercase letters, numbers, and underscores.'));
       }
     }
     else {
-      form_error($element, $element['#machine_name']['error']);
+      form_error($element, $form_state, $element['#machine_name']['error']);
     }
   }
 
@@ -1919,7 +1919,7 @@ function form_validate_machine_name(&$element, &$form_state) {
   if ($element['#default_value'] !== $element['#value']) {
     $function = $element['#machine_name']['exists'];
     if (call_user_func($function, $element['#value'], $element, $form_state)) {
-      form_error($element, t('The machine-readable name is already in use. It must be unique.'));
+      form_error($element, $form_state, t('The machine-readable name is already in use. It must be unique.'));
     }
   }
 }
@@ -2339,7 +2339,7 @@ function form_validate_email(&$element, &$form_state) {
   form_set_value($element, $value, $form_state);
 
   if ($value !== '' && !valid_email_address($value)) {
-    form_error($element, t('The e-mail address %mail is not valid.', array('%mail' => $value)));
+    form_error($element, $form_state, t('The e-mail address %mail is not valid.', array('%mail' => $value)));
   }
 }
 
@@ -2415,18 +2415,18 @@ function form_validate_number(&$element, &$form_state) {
 
   // Ensure the input is numeric.
   if (!is_numeric($value)) {
-    form_error($element, t('%name must be a number.', array('%name' => $name)));
+    form_error($element, $form_state, t('%name must be a number.', array('%name' => $name)));
     return;
   }
 
   // Ensure that the input is greater than the #min property, if set.
   if (isset($element['#min']) && $value < $element['#min']) {
-    form_error($element, t('%name must be higher than or equal to %min.', array('%name' => $name, '%min' => $element['#min'])));
+    form_error($element, $form_state, t('%name must be higher than or equal to %min.', array('%name' => $name, '%min' => $element['#min'])));
   }
 
   // Ensure that the input is less than the #max property, if set.
   if (isset($element['#max']) && $value > $element['#max']) {
-    form_error($element, t('%name must be lower than or equal to %max.', array('%name' => $name, '%max' => $element['#max'])));
+    form_error($element, $form_state, t('%name must be lower than or equal to %max.', array('%name' => $name, '%max' => $element['#max'])));
   }
 
   if (isset($element['#step']) && strtolower($element['#step']) != 'any') {
@@ -2435,7 +2435,7 @@ function form_validate_number(&$element, &$form_state) {
     $offset = isset($element['#min']) ? $element['#min'] : 0.0;
 
     if (!Number::validStep($value, $element['#step'], $offset)) {
-      form_error($element, t('%name is not a valid number.', array('%name' => $name)));
+      form_error($element, $form_state, t('%name is not a valid number.', array('%name' => $name)));
     }
   }
 }
@@ -2518,7 +2518,7 @@ function form_validate_url(&$element, &$form_state) {
   form_set_value($element, $value, $form_state);
 
   if ($value !== '' && !valid_url($value, TRUE)) {
-    form_error($element, t('The URL %url is not valid.', array('%url' => $value)));
+    form_error($element, $form_state, t('The URL %url is not valid.', array('%url' => $value)));
   }
 }
 
@@ -2539,7 +2539,7 @@ function form_validate_color(&$element, &$form_state) {
       form_set_value($element, Color::rgbToHex(Color::hexToRgb($value)), $form_state);
     }
     catch (InvalidArgumentException $e) {
-      form_error($element, t('%name must be a valid color.', array('%name' => empty($element['#title']) ? $element['#parents'][0] : $element['#title'])));
+      form_error($element, $form_state, t('%name must be a valid color.', array('%name' => empty($element['#title']) ? $element['#parents'][0] : $element['#title'])));
     }
   }
 }
@@ -2908,7 +2908,7 @@ function _form_set_attributes(&$element, $class = array()) {
     $element['#attributes']['required'] = 'required';
     $element['#attributes']['aria-required'] = 'true';
   }
-  if (isset($element['#parents']) && form_get_error($element) !== NULL && !empty($element['#validated'])) {
+  if (isset($element['#parents']) && isset($element['#errors']) && !empty($element['#validated'])) {
     $element['#attributes']['class'][] = 'error';
     $element['#attributes']['aria-invalid'] = 'true';
   }

core/includes/install.core.inc

@@ -653,7 +653,7 @@ function install_run_task($task, &$install_state) {
         'build_info' => array('args' => array(&$install_state)),
       );
       drupal_form_submit($function, $form_state);
-      $errors = form_get_errors();
+      $errors = form_get_errors($form_state);
       if (!empty($errors)) {
         throw new Exception(implode("\n", $errors));
       }
@@ -1192,7 +1192,7 @@ function install_settings_form_validate($form, &$form_state) {
   $form_state['storage']['database'] = $database;
   $errors = install_database_errors($database, $form_state['values']['settings_file']);
   foreach ($errors as $name => $message) {
-    form_set_error($name, $message);
+    form_set_error($name, $form_state, $message);
   }
 }
 
@@ -2699,7 +2699,7 @@ function _install_configure_form($form, &$form_state, &$install_state) {
  */
 function install_configure_form_validate($form, &$form_state) {
   if ($error = user_validate_name($form_state['values']['account']['name'])) {
-    form_error($form['admin_account']['account']['name'], $error);
+    form_error($form['admin_account']['account']['name'], $form_state, $error);
   }
 }
 

core/lib/Drupal/Core/Field/WidgetBase.php

@@ -359,7 +359,7 @@ public function flagErrors(FieldItemListInterface $items, array $form, array &$f
             // @todo: Pass $violation->arrayPropertyPath as property path.
             $error_element = $this->errorElement($delta_element, $violation, $form, $form_state);
             if ($error_element !== FALSE) {
-              form_error($error_element, $violation->getMessage());
+              form_error($error_element, $form_state, $violation->getMessage());
             }
           }
         }

core/lib/Drupal/Core/Form/FormBuilder.php

@@ -103,20 +103,6 @@ class FormBuilder implements FormBuilderInterface {
    */
   protected $forms;
 
-  /**
-   * An array of form errors.
-   *
-   * @var array
-   */
-  protected $errors = array();
-
-  /**
-   * @todo.
-   *
-   * @var array
-   */
-  protected $errorSections;
-
   /**
    * An array of validated forms.
    *
@@ -317,6 +303,8 @@ public function getFormStateDefaults() {
       'method' => 'post',
       'groups' => array(),
       'buttons' => array(),
+      'errors' => array(),
+      'limit_validation_errors' => NULL,
     );
   }
 
@@ -441,6 +429,8 @@ protected function getUncacheableKeys() {
       'executed',
       'validate_handlers',
       'values',
+      'errors',
+      'limit_validation_errors',
     );
   }
 
@@ -472,7 +462,7 @@ public function submitForm($form_arg, &$form_state) {
 
     // Reset form validation.
     $form_state['must_validate'] = TRUE;
-    $this->clearErrors();
+    $this->clearErrors($form_state);
 
     $this->prepareForm($form_id, $form, $form_state);
     $this->processForm($form_id, $form, $form_state);
@@ -608,12 +598,12 @@ public function processForm($form_id, &$form, &$form_state) {
       // form is processed, so scenarios that result in the form being built
       // behind the scenes and again for the browser don't increment all the
       // element IDs needlessly.
-      if (!$this->getErrors()) {
+      if (!$this->getAnyErrors()) {
         // In case of errors, do not break HTML IDs of other forms.
         $this->drupalStaticReset('drupal_html_id');
       }
 
-      if ($form_state['submitted'] && !$this->getErrors() && !$form_state['rebuild']) {
+      if ($form_state['submitted'] && !$this->getAnyErrors() && !$form_state['rebuild']) {
         // Execute form submit handlers.
         $this->executeHandlers('submit', $form, $form_state);
 
@@ -678,7 +668,7 @@ public function processForm($form_id, &$form, &$form_state) {
       //   along with element-level #submit properties, it makes no sense to
       //   have divergent form execution based on whether the triggering element
       //   has #executes_submit_callback set to TRUE.
-      if (($form_state['rebuild'] || !$form_state['executed']) && !$this->getErrors()) {
+      if (($form_state['rebuild'] || !$form_state['executed']) && !$this->getAnyErrors()) {
         // Form building functions (e.g., self::handleInputElement()) may use
         // $form_state['rebuild'] to determine if they are running in the
         // context of a rebuild, so ensure it is set.
@@ -852,11 +842,15 @@ public function validateForm($form_id, &$form, &$form_state) {
         $url = $this->urlGenerator->generateFromPath($path, array('query' => $query));
 
         // Setting this error will cause the form to fail validation.
-        $this->setErrorByName('form_token', $this->t('The form has become outdated. Copy any unsaved work in the form below and then <a href="@link">reload this page</a>.', array('@link' => $url)));
+        $this->setErrorByName('form_token', $form_state, $this->t('The form has become outdated. Copy any unsaved work in the form below and then <a href="@link">reload this page</a>.', array('@link' => $url)));
       }
     }
 
+    // Recursively validate each form element.
     $this->doValidateForm($form, $form_state, $form_id);
+    // After validation, loop through and assign each element its errors.
+    $this->setElementErrorsFromFormState($form, $form_state);
+    // Mark this form as validated.
     $this->validatedForms[$form_id] = TRUE;
 
     // If validation errors are limited then remove any non validated form values,
@@ -1010,7 +1004,7 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
       if (isset($elements['#needs_validation'])) {
         // Verify that the value is not longer than #maxlength.
         if (isset($elements['#maxlength']) && Unicode::strlen($elements['#value']) > $elements['#maxlength']) {
-          $this->setError($elements, $this->t('!name cannot be longer than %max characters but is currently %length characters long.', array('!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title'], '%max' => $elements['#maxlength'], '%length' => Unicode::strlen($elements['#value']))));
+          $this->setError($elements, $form_state, $this->t('!name cannot be longer than %max characters but is currently %length characters long.', array('!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title'], '%max' => $elements['#maxlength'], '%length' => Unicode::strlen($elements['#value']))));
         }
 
         if (isset($elements['#options']) && isset($elements['#value'])) {
@@ -1024,7 +1018,7 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
             $value = in_array($elements['#type'], array('checkboxes', 'tableselect')) ? array_keys($elements['#value']) : $elements['#value'];
             foreach ($value as $v) {
               if (!isset($options[$v])) {
-                $this->setError($elements, $this->t('An illegal choice has been detected. Please contact the site administrator.'));
+                $this->setError($elements, $form_state, $this->t('An illegal choice has been detected. Please contact the site administrator.'));
                 $this->watchdog('form', 'Illegal choice %choice in !name element.', array('%choice' => $v, '!name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
               }
             }
@@ -1043,7 +1037,7 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
             $this->setValue($elements, NULL, $form_state);
           }
           elseif (!isset($options[$elements['#value']])) {
-            $this->setError($elements, $this->t('An illegal choice has been detected. Please contact the site administrator.'));
+            $this->setError($elements, $form_state, $this->t('An illegal choice has been detected. Please contact the site administrator.'));
             $this->watchdog('form', 'Illegal choice %choice in %name element.', array('%choice' => $elements['#value'], '%name' => empty($elements['#title']) ? $elements['#parents'][0] : $elements['#title']), WATCHDOG_ERROR);
           }
         }
@@ -1061,7 +1055,7 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
       // too large a security risk to have any invalid user input when executing
       // form-level submit handlers.
       if (isset($form_state['triggering_element']['#limit_validation_errors']) && ($form_state['triggering_element']['#limit_validation_errors'] !== FALSE) && !($form_state['submitted'] && !isset($form_state['triggering_element']['#submit']))) {
-        $this->setErrorByName(NULL, '', $form_state['triggering_element']['#limit_validation_errors']);
+        $form_state['limit_validation_errors'] = $form_state['triggering_element']['#limit_validation_errors'];
       }
       // If submit handlers won't run (due to the submission having been
       // triggered by an element whose #executes_submit_callback property isn't
@@ -1073,14 +1067,14 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
       // system_element_info()), so that full validation is their default
       // behavior.
       elseif (isset($form_state['triggering_element']) && !isset($form_state['triggering_element']['#limit_validation_errors']) && !$form_state['submitted']) {
-        $this->setErrorByName(NULL, '', array());
+        $form_state['limit_validation_errors'] = array();
       }
       // As an extra security measure, explicitly turn off error suppression if
       // one of the above conditions wasn't met. Since this is also done at the
       // end of this function, doing it here is only to handle the rare edge
       // case where a validate handler invokes form processing of another form.
       else {
-        $this->errorSections = NULL;
+        $form_state['limit_validation_errors'] = NULL;
       }
 
       // Make sure a value is passed when the field is required.
@@ -1120,17 +1114,17 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
       // variables are also known to be defined and we can test them again.
       if (isset($is_empty_value) && ($is_empty_multiple || $is_empty_string || $is_empty_value)) {
         if (isset($elements['#required_error'])) {
-          $this->setError($elements, $elements['#required_error']);
+          $this->setError($elements, $form_state, $elements['#required_error']);
         }
         // A #title is not mandatory for form elements, but without it we cannot
         // set a form error message. So when a visible title is undesirable,
         // form constructors are encouraged to set #title anyway, and then set
         // #title_display to 'invisible'. This improves accessibility.
         elseif (isset($elements['#title'])) {
-          $this->setError($elements, $this->t('!name field is required.', array('!name' => $elements['#title'])));
+          $this->setError($elements, $form_state, $this->t('!name field is required.', array('!name' => $elements['#title'])));
         }
         else {
-          $this->setError($elements);
+          $this->setError($elements, $form_state);
         }
       }
 
@@ -1140,7 +1134,30 @@ protected function doValidateForm(&$elements, &$form_state, $form_id = NULL) {
     // Done validating this element, so turn off error suppression.
     // self::doValidateForm() turns it on again when starting on the next
     // element, if it's still appropriate to do so.
-    $this->errorSections = NULL;
+    $form_state['limit_validation_errors'] = NULL;
+  }
+
+  /**
+   * Stores the errors of each element directly on the element.
+   *
+   * Because self::getError() and self::getErrors() require the $form_state,
+   * we must provide a way for non-form functions to check the errors for a
+   * specific element. The most common usage of this is a #pre_render callback.
+   *
+   * @param array $elements
+   *   An associative array containing the structure of a form element.
+   * @param array $form_state
+   *   An associative array containing the current state of the form.
+   */
+  protected function setElementErrorsFromFormState(array &$elements, array &$form_state) {
+    // Recurse through all children.
+    foreach ($this->elementChildren($elements) as $key) {
+      if (isset($elements[$key]) && $elements[$key]) {
+        $this->setElementErrorsFromFormState($elements[$key], $form_state);
+      }
+    }
+    // Store the errors for this element on the element directly.
+    $elements['#errors'] = $this->getError($elements, $form_state);
   }
 
   /**
@@ -1179,14 +1196,10 @@ public function executeHandlers($type, &$form, &$form_state) {
   /**
    * {@inheritdoc}
    */
-  public function setErrorByName($name = NULL, $message = '', $limit_validation_errors = NULL) {
-    if (isset($limit_validation_errors)) {
-      $this->errorSections = $limit_validation_errors;
-    }
-
-    if (isset($name) && !isset($this->errors[$name])) {
+  public function setErrorByName($name, array &$form_state, $message = '') {
+    if (!isset($form_state['errors'][$name])) {
       $record = TRUE;
-      if (isset($this->errorSections)) {
+      if (isset($form_state['limit_validation_errors'])) {
         // #limit_validation_errors is an array of "sections" within which user
         // input must be valid. If the element is within one of these sections,
         // the error must be recorded. Otherwise, it can be suppressed.
@@ -1195,7 +1208,7 @@ public function setErrorByName($name = NULL, $message = '', $limit_validation_er
         // its submit action to be triggered even if none of the submitted
         // values are valid.
         $record = FALSE;
-        foreach ($this->errorSections as $section) {
+        foreach ($form_state['limit_validation_errors'] as $section) {
           // Exploding by '][' reconstructs the element's #parents. If the
           // reconstructed #parents begin with the same keys as the specified
           // section, then the element's values are within the part of
@@ -1210,44 +1223,51 @@ public function setErrorByName($name = NULL, $message = '', $limit_validation_er
         }
       }
       if ($record) {
-        $this->errors[$name] = $message;
+        $form_state['errors'][$name] = $message;
+        $this->request->attributes->set('_form_errors', TRUE);
         if ($message) {
           $this->drupalSetMessage($message, 'error');
         }
       }
     }
 
-    return $this->errors;
+    return $form_state['errors'];
   }
 
   /**
    * {@inheritdoc}
    */
-  public function clearErrors() {
-    $this->errors = array();
+  public function clearErrors(array &$form_state) {
+    $form_state['errors'] = array();
+    $this->request->attributes->set('_form_errors', FALSE);
   }
 
   /**
    * {@inheritdoc}
    */
-  public function getErrors() {
-    $form = $this->setErrorByName();
-    if (!empty($form)) {
-      return $form;
-    }
+  public function getErrors(array $form_state) {
+    return $form_state['errors'];
   }
 
   /**
    * {@inheritdoc}
    */
-  public function getError($element) {
-    $form = $this->setErrorByName();
-    $parents = array();
-    foreach ($element['#parents'] as $parent) {
-      $parents[] = $parent;
-      $key = implode('][', $parents);
-      if (isset($form[$key])) {
-        return $form[$key];
+  public function getAnyErrors() {
+    return (bool) $this->request->attributes->get('_form_errors');
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getError($element, array &$form_state) {
+    if ($errors = $this->getErrors($form_state)) {
+      $parents = array();
+      foreach ($element['#parents'] as $parent) {
+        $parents[] = $parent;
+        $key = implode('][', $parents);
+        if (isset($errors[$key])) {
+          return $errors[$key];
+        }
       }
     }
   }
@@ -1255,8 +1275,8 @@ public function getError($element) {
   /**
    * {@inheritdoc}
    */
-  public function setError(&$element, $message = '') {
-    $this->setErrorByName(implode('][', $element['#parents']), $message);
+  public function setError(&$element, array &$form_state, $message = '') {
+    $this->setErrorByName(implode('][', $element['#parents']), $form_state, $message);
   }
 
   /**
@@ -1277,6 +1297,7 @@ public function doBuildForm($form_id, &$element, &$form_state) {
       '#required' => FALSE,
       '#attributes' => array(),
       '#title_display' => 'before',
+      '#errors' => NULL,
     );
 
     // Special handling if we're on the top level form element.

core/lib/Drupal/Core/Form/FormBuilderInterface.php

@@ -12,7 +12,7 @@
 /**
  * Provides an interface for form building and processing.
  */
-interface FormBuilderInterface {
+interface FormBuilderInterface extends FormErrorInterface {
 
   /**
    * Determines the form ID.
@@ -508,128 +508,6 @@ public function redirectForm($form_state);
    */
   public function executeHandlers($type, &$form, &$form_state);
 
-  /**
-   * Files an error against a form element.
-   *
-   * When a validation error is detected, the validator calls form_set_error()
-   * to indicate which element needs to be changed and provide an error message.
-   * This causes the Form API to not execute the form submit handlers, and
-   * instead to re-display the form to the user with the corresponding elements
-   * rendered with an 'error' CSS class (shown as red by default).
-   *
-   * The standard form_set_error() behavior can be changed if a button provides
-   * the #limit_validation_errors property. Multistep forms not wanting to
-   * validate the whole form can set #limit_validation_errors on buttons to
-   * limit validation errors to only certain elements. For example, pressing the
-   * "Previous" button in a multistep form should not fire validation errors
-   * just because the current step has invalid values. If
-   * #limit_validation_errors is set on a clicked button, the button must also
-   * define a #submit property (may be set to an empty array). Any #submit
-   * handlers will be executed even if there is invalid input, so extreme care
-   * should be taken with respect to any actions taken by them. This is
-   * typically not a problem with buttons like "Previous" or "Add more" that do
-   * not invoke persistent storage of the submitted form values. Do not use the
-   * #limit_validation_errors property on buttons that trigger saving of form
-   * values to the database.
-   *
-   * The #limit_validation_errors property is a list of "sections" within
-   * $form_state['values'] that must contain valid values. Each "section" is an
-   * array with the ordered set of keys needed to reach that part of
-   * $form_state['values'] (i.e., the #parents property of the element).
-   *
-   * Example 1: Allow the "Previous" button to function, regardless of whether
-   * any user input is valid.
-   *
-   * @code
-   *   $form['actions']['previous'] = array(
-   *     '#type' => 'submit',
-   *     '#value' => t('Previous'),
-   *     '#limit_validation_errors' => array(),       // No validation.
-   *     '#submit' => array('some_submit_function'),  // #submit required.
-   *   );
-   * @endcode
-   *
-   * Example 2: Require some, but not all, user input to be valid to process the
-   * submission of a "Previous" button.
-   *
-   * @code
-   *   $form['actions']['previous'] = array(
-   *     '#type' => 'submit',
-   *     '#value' => t('Previous'),