Index: modules/simpletest/tests/form_test.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/form_test.module,v
retrieving revision 1.1
diff -u -r1.1 form_test.module
--- modules/simpletest/tests/form_test.module	28 Jan 2009 07:43:26 -0000	1.1
+++ modules/simpletest/tests/form_test.module	15 Mar 2009 21:53:36 -0000
@@ -180,3 +180,32 @@
 
   return _form_test_tableselect_form_builder($form_state, $options);
 }
+
+/**
+ * Dummy form used to test programmatic form submits.
+ */
+function _form_test_dummy_form($form_state) {
+  return array(
+    'dummyfield' => array(
+      '#title' => 'Dummyfield',
+      '#type' => 'textfield'
+    )
+  );
+}
+
+/**
+ * In order to test the validation handler, the dummy value 
+ * is explicitly required.
+ */
+function _form_test_dummy_form_validate($form, &$form_state) {
+  if (empty($form_state['values']['dummyfield'])) {
+    form_set_error('dummyfield', t('This field is required although dummy.'));
+  }
+}
+
+/**
+ * Process the submitted dummy value.
+ */
+function _form_test_dummy_form_submit($form, &$form_state) {
+  $form_state['dummy_submit'] = $form_state['values']['dummyfield'];
+}
Index: modules/simpletest/tests/form.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/simpletest/tests/form.test,v
retrieving revision 1.4
diff -u -r1.4 form.test
--- modules/simpletest/tests/form.test	14 Mar 2009 20:13:27 -0000	1.4
+++ modules/simpletest/tests/form.test	15 Mar 2009 21:53:36 -0000
@@ -315,3 +315,56 @@
 
 }
 
+/**
+ * Test the programmatic form submit behavior.
+ */
+class FormsProgrammaticSubmitFunctionalTest extends DrupalWebTestCase {
+
+  function getInfo() {
+    return array(
+      'name' => t('Programmatically submitted forms test'),
+      'description' => t('Test the programmatic form submit behavior.'),
+      'group' => t('Form API'),
+    );
+  }
+
+  function setUp() {
+    parent::setUp('form_test');
+  }
+  
+  /**
+   * Test multiple programmatic form submits (see http://drupal.org/node/260934).
+   */
+  function testMultipleSubmit() {
+    // Backup the current batch status and reset it to avoid conflicts
+    // while processing the dummy form submit handler.
+    $current_batch = $batch =& batch_get();
+    $batch = array();
+    
+    $this->submitDummyForm();
+    $this->submitDummyForm('test 1');
+    $this->submitDummyForm();
+    $this->submitDummyForm('test 2');
+    
+    // Restore the current batch status.
+    $batch = $current_batch;
+  }
+  
+  /**
+   * Helper function used to programmatically submit the dummy form
+   * defined in form_test.module with the given value.
+   *
+   * @param string $value
+   *   The dummyfield submitted value.
+   */
+  private function submitDummyForm($value = NULL) {
+    $form_state = array('values' => array('dummyfield' => $value));
+    drupal_execute('_form_test_dummy_form', $form_state);
+    $errors = form_get_errors();
+    $valid_form = empty($errors);
+    $result = empty($value) ? !$valid_form : $valid_form;
+    $args = array('%value' => $value, '%errors' => $valid_form ? '' : implode(' ', $errors));
+    $this->assertTrue($result, t('Dummyfield value: %value<br/>Error: %errors', $args));
+    $this->assertTrue(!$valid_form || $form_state['dummy_submit'] == $value, t('Form executed'));
+  }
+}
Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.324
diff -u -r1.324 form.inc
--- includes/form.inc	14 Mar 2009 20:13:26 -0000	1.324
+++ includes/form.inc	15 Mar 2009 21:53:36 -0000
@@ -377,9 +377,12 @@
   $form = drupal_retrieve_form($form_id, $form_state);
   $form_state['input'] = $form_state['values'];
   $form_state['programmed'] = TRUE;
+  $form_state['must_validate'] = TRUE;
   // Merge in default values.
   $form_state += form_state_defaults();
 
+  _form_set_current($form);
+
   drupal_prepare_form($form_id, $form, $form_state);
   drupal_process_form($form_id, $form, $form_state);
 }
@@ -669,7 +672,6 @@
       form_set_error('form_token', t('Validation error, please try again. If this error persists, please contact the site administrator.'));
     }
   }
-
   _form_validate($form, $form_state, $form_id);
   $validated_forms[$form_id] = TRUE;
 }
@@ -892,13 +894,14 @@
   if ($reset) {
     $form = array();
   }
-  if (isset($name) && !isset($form[$name])) {
-    $form[$name] = $message;
+  $build_id = _form_set_current();
+  if (isset($name) && !isset($form[$build_id][$name])) {
+    $form[$build_id][$name] = $message;
     if ($message) {
       drupal_set_message($message, 'error');
     }
   }
-  return $form;
+  return isset($form[$build_id]) ? $form[$build_id] : array();
 }
 
 /**
@@ -1443,6 +1446,17 @@
   }
 }
 
+/**
+ * Stores the current form build id, generating it if missing.
+ */
+function _form_set_current(&$form = NULL) {
+  static $current = 'form-current';
+  if (isset($form)) {
+    $current = isset($form['#build_id']) ? $form['#build_id'] : 'form-'. md5(uniqid(mt_rand(), TRUE));
+  }
+  return $current;
+}
+
 function form_options_flatten($array, $reset = TRUE) {
   static $return;