Undefined offset: 0 in views_handler_field_field

Confirmed.

I believe problem initiates in field_collection_field_formatter_links() which doesn't check $items and when its empty still adds data to the $element array but with index -1:

if (empty($element['#suffix'])) {
    $index = count(element_children($element)) - 1; // would be -1 if element_children() returns empty result
    $element[$index]['#attributes']['class'][] = 'field-collection-view-final';
}

So we having $elements array with the nice element:

-1	Array [1]	
	[0...0]	
		#attributes	Array [1]	
			[0...0]	
				class	Array [1]	
					...

Later in field.default.inc:232

  $addition[$field['field_name']] = array_merge($info, $elements);

merging produces empty element:

0	Array [1]	
	[0...0]	
		#attributes	Array [1]	
			[0...0]	
				class	Array [1]	
                                        ....

Finally in views/modules/field/views_handler_field_field.inc.views_handler_field_field->set_items(), $render_array is now containing this element which makes element_children($render_array) to return key as there were a proper element to render, while there's not.

    foreach (element_children($render_array) as $count) {
      $items[$count]['rendered'] = $render_array[$count];
      $items[$count]['raw'] = $render_array['#items'][$count]; // this line trigger's Notice
    }

Many words, but the patch is trivial. Attached.

Updated patch. Things go a bit tricky.

To get anything rendered in view fields, $render_array from
views/modules/field/views_handler_field_field.inc.views_handler_field_field->set_items()
should has both #items and corresponding renderable children.
In case when we have Add link but have no items, it will never be rendered, since it dones't produce good child.
So we can add fake child.
See the patch.

Oops, old school patch failed.
Giving a try to new style, created with diff -upr.

The code changes from #5 fixed the issue for me. Attached is a patch with the same changes from #5, but created with "git diff."

i can confirm this issue and the last solution #6 worked for me. thank you

I've also experienced this issue and the patch in #6 solved this error message for me.

The original patch doesn't apply anymore. Also I cannot reproduce the originally reported bug anymore. It seems that the patch had to wait too long in the issue queue and became stale.