Add trim filter to first, middle and lastname.

The additional trim form field data filter was created and added as
input filter to the firstname, lastname and middlename fields
of the customer_address and customer entities.

Tickets: magento#10415

app/code/Magento/Customer/Setup/UpgradeData.php

@@ -159,6 +159,10 @@ public function upgrade(ModuleDataSetupInterface $setup, ModuleContextInterface
             $this->upgradeVersionTwoZeroTwelve($customerSetup);
         }
 
+        if (version_compare($context->getVersion(), '2.0.13', '<')) {
+            $this->upgradeVersionTwoZeroThirteen($customerSetup);
+        }
+
         $indexer = $this->indexerRegistry->get(Customer::CUSTOMER_GRID_INDEXER_ID);
         $indexer->reindexAll();
         $this->eavConfig->clear();
@@ -663,4 +667,36 @@ private function upgradeCustomerPasswordResetlinkExpirationPeriodConfig($setup)
             ['path = ?' => \Magento\Customer\Model\Customer::XML_PATH_CUSTOMER_RESET_PASSWORD_LINK_EXPIRATION_PERIOD]
         );
     }
+
+    /**
+     * @param CustomerSetup $customerSetup
+     */
+    private function upgradeVersionTwoZeroThirteen(CustomerSetup $customerSetup)
+    {
+        $entityAttributes = [
+            'customer_address' => [
+                'firstname' => [
+                    'input_filter' => 'trim'
+                ],
+                'lastname' => [
+                    'input_filter' => 'trim'
+                ],
+                'middlename' => [
+                    'input_filter' => 'trim'
+                ],
+            ],
+            'customer' => [
+                'firstname' => [
+                    'input_filter' => 'trim'
+                ],
+                'lastname' => [
+                    'input_filter' => 'trim'
+                ],
+                'middlename' => [
+                    'input_filter' => 'trim'
+                ],
+            ],
+        ];
+        $this->upgradeAttributes($entityAttributes, $customerSetup);
+    }
 }

app/code/Magento/Customer/etc/module.xml

@@ -6,7 +6,7 @@
  */
 -->
 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
-    <module name="Magento_Customer" setup_version="2.0.12">
+    <module name="Magento_Customer" setup_version="2.0.13">
         <sequence>
             <module name="Magento_Eav"/>
             <module name="Magento_Directory"/>

lib/internal/Magento/Framework/Data/Form/Filter/Trim.php

@@ -0,0 +1,37 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+/**
+ * Form Input/Output Trim Filter
+ *
+ * @author      Magento Core Team <core@magentocommerce.com>
+ */
+namespace Magento\Framework\Data\Form\Filter;
+
+class Trim implements \Magento\Framework\Data\Form\Filter\FilterInterface
+{
+    /**
+     * Returns the result of filtering $value
+     *
+     * @param string $value
+     * @return string
+     */
+    public function inputFilter($value)
+    {
+        return trim($value, ' ');
+    }
+
+    /**
+     * Returns the result of filtering $value
+     *
+     * @param string $value
+     * @return string
+     */
+    public function outputFilter($value)
+    {
+        return $value;
+    }
+}