Change record status: 
Project: 
Introduced in branch: 
8.x
Description: 

#autocomplete_path is removed and replaced with #autocomplete_route_name and #autocomplete_parameters

D7

<?php
  $form
['name'] = array(
   
'#type' => 'textfield',
   
'#autocomplete_path' => 'user/autocomplete',
  );
?>

D8

<?php
  $form
['name'] = array(
   
'#type' => 'textfield',
   
'#autocomplete_route_name' => 'user_autocomplete',
  );
?>

If values need to be appended to the end of the path, like the taxonomy term autocomplete, there is an #autocomplete_route_parameters property that takes an associative array of parameters. The keys must match the method parameters of the autocomplete controller.

D7

<?php
  $form
['term'] = array(
   
'#type' => 'textfield',
   
'#autocomplete_path' => 'taxonomy/autocomplete/' . $field_name,
  );
?>

D8

<?php
  $form
['term'] = array(
   
'#type' => 'textfield',
   
'#autocomplete_route_name' => 'taxonomy_autocomplete',
   
'#autocomplete_route_parameters' => array('field_name' => $field_name),
  );
?>
Impacts: 
Module developers
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done