⏫ Forwardport of #11462 to 2.3-develop branch

Applied pull request patch https://github.com/magento/magento2/pull/11462.patch (created by @avstudnitz) based on commit(s):
  1. 11e38f6
  2. 7800e5d
  3. 252529f
  4. 519b805
  5. eb79b38
  6. fce3afe
  7. 3e38118

Fixed GitHub Issues in 2.3-develop branch:
  - #7241: No option to start with blank option for prefix and suffix in checkout. (reported by @spyrule)

app/code/Magento/Config/Model/Config/Source/Nooptreq.php

@@ -11,15 +11,19 @@
  */
 class Nooptreq implements \Magento\Framework\Option\ArrayInterface
 {
+    const VALUE_NO = '';
+    const VALUE_OPTIONAL = 'opt';
+    const VALUE_REQUIRED = 'req';
+
     /**
      * @return array
      */
     public function toOptionArray()
     {
         return [
-            ['value' => '', 'label' => __('No')],
-            ['value' => 'opt', 'label' => __('Optional')],
-            ['value' => 'req', 'label' => __('Required')]
+            ['value' => self::VALUE_NO, 'label' => __('No')],
+            ['value' => self::VALUE_OPTIONAL, 'label' => __('Optional')],
+            ['value' => self::VALUE_REQUIRED, 'label' => __('Required')]
         ];
     }
 }

app/code/Magento/Customer/Block/Widget/Name.php

@@ -106,8 +106,11 @@ public function getPrefixOptions()
         $prefixOptions = $this->options->getNamePrefixOptions();
 
         if ($this->getObject() && !empty($prefixOptions)) {
-            $oldPrefix = $this->escapeHtml(trim($this->getObject()->getPrefix()));
-            $prefixOptions[$oldPrefix] = $oldPrefix;
+            $prefixOption = $this->getObject()->getPrefix();
+            $oldPrefix = $this->escapeHtml(trim($prefixOption));
+            if ($prefixOption !== null && !isset($prefixOptions[$oldPrefix]) && !isset($prefixOptions[$prefixOption])) {
+                $prefixOptions[$oldPrefix] = $oldPrefix;
+            }
         }
         return $prefixOptions;
     }
@@ -161,8 +164,11 @@ public function getSuffixOptions()
     {
         $suffixOptions = $this->options->getNameSuffixOptions();
         if ($this->getObject() && !empty($suffixOptions)) {
-            $oldSuffix = $this->escapeHtml(trim($this->getObject()->getSuffix()));
-            $suffixOptions[$oldSuffix] = $oldSuffix;
+            $suffixOption = $this->getObject()->getSuffix();
+            $oldSuffix = $this->escapeHtml(trim($suffixOption));
+            if ($suffixOption !== null && !isset($suffixOptions[$oldSuffix]) && !isset($suffixOptions[$suffixOption])) {
+                $suffixOptions[$oldSuffix] = $oldSuffix;
+            }
         }
         return $suffixOptions;
     }

app/code/Magento/Customer/Model/Options.php

@@ -5,6 +5,7 @@
  */
 namespace Magento\Customer\Model;
 
+use Magento\Config\Model\Config\Source\Nooptreq as NooptreqSource;
 use Magento\Customer\Helper\Address as AddressHelper;
 use Magento\Framework\Escaper;
 
@@ -42,7 +43,10 @@ public function __construct(
      */
     public function getNamePrefixOptions($store = null)
     {
-        return $this->_prepareNamePrefixSuffixOptions($this->addressHelper->getConfig('prefix_options', $store));
+        return $this->prepareNamePrefixSuffixOptions(
+            $this->addressHelper->getConfig('prefix_options', $store),
+            $this->addressHelper->getConfig('prefix_show', $store) == NooptreqSource::VALUE_OPTIONAL
+        );
     }
 
     /**
@@ -53,16 +57,34 @@ public function getNamePrefixOptions($store = null)
      */
     public function getNameSuffixOptions($store = null)
     {
-        return $this->_prepareNamePrefixSuffixOptions($this->addressHelper->getConfig('suffix_options', $store));
+        return $this->prepareNamePrefixSuffixOptions(
+            $this->addressHelper->getConfig('suffix_options', $store),
+            $this->addressHelper->getConfig('suffix_show', $store) == NooptreqSource::VALUE_OPTIONAL
+        );
+    }
+
+    /**
+     * @param $options
+     * @param bool $isOptional
+     * @return array|bool
+     *
+     * @deprecated
+     * @see prepareNamePrefixSuffixOptions()
+     */
+    protected function _prepareNamePrefixSuffixOptions($options, $isOptional = false)
+    {
+        return $this->prepareNamePrefixSuffixOptions($options, $isOptional);
     }
 
     /**
      * Unserialize and clear name prefix or suffix options
+     * If field is optional, add an empty first option.
      *
      * @param string $options
+     * @param bool $isOptional
      * @return array|bool
      */
-    protected function _prepareNamePrefixSuffixOptions($options)
+    private function prepareNamePrefixSuffixOptions($options, $isOptional = false)
     {
         $options = trim($options);
         if (empty($options)) {
@@ -74,6 +96,10 @@ protected function _prepareNamePrefixSuffixOptions($options)
             $value = $this->escaper->escapeHtml(trim($value));
             $result[$value] = $value;
         }
+        if ($isOptional && trim(current($options))) {
+            $result = array_merge([' ' => ' '], $result);
+        }
+
         return $result;
     }
 }

app/code/Magento/Customer/etc/adminhtml/system.xml

@@ -209,7 +209,7 @@
                 <field id="prefix_options" translate="label comment" sortOrder="30" showInDefault="1" showInWebsite="1" showInStore="0">
                     <label>Prefix Dropdown Options</label>
                     <comment>
-                        <![CDATA[Semicolon (;) separated values.<br/>Put semicolon in the beginning for empty first option.<br/>Leave empty for open text field.]]>
+                        <![CDATA[Semicolon (;) separated values.<br/>Leave empty for open text field.]]>
                     </comment>
                 </field>
                 <field id="middlename_show" translate="label comment" type="select" sortOrder="40" showInDefault="1" showInWebsite="1" showInStore="0">
@@ -227,7 +227,7 @@
                 <field id="suffix_options" translate="label comment" sortOrder="60" showInDefault="1" showInWebsite="1" showInStore="0">
                     <label>Suffix Dropdown Options</label>
                     <comment>
-                        <![CDATA[Semicolon (;) separated values.<br/>Put semicolon in the beginning for empty first option.<br/>Leave empty for open text field.]]>
+                        <![CDATA[Semicolon (;) separated values.<br/>Leave empty for open text field.]]>
                     </comment>
                 </field>
                 <field id="dob_show" translate="label" type="select" sortOrder="70" showInDefault="1" showInWebsite="1" showInStore="0">

app/code/Magento/Customer/i18n/en_US.csv

@@ -479,9 +479,9 @@ Strong,Strong
 "The title that goes before name (Mr., Mrs., etc.)","The title that goes before name (Mr., Mrs., etc.)"
 "Prefix Dropdown Options","Prefix Dropdown Options"
 "
-                        Semicolon (;) separated values.<br/>Put semicolon in the beginning for empty first option.<br/>Leave empty for open text field.
+                        Semicolon (;) separated values.<br/>Leave empty for open text field.
                     ","
-                        Semicolon (;) separated values.<br/>Put semicolon in the beginning for empty first option.<br/>Leave empty for open text field.
+                        Semicolon (;) separated values.<br/>Leave empty for open text field.
                     "
 "Show Middle Name (initial)","Show Middle Name (initial)"
 "Always optional.","Always optional."