From aa6f853584182980c1c7d12891b689317e458b8b Mon Sep 17 00:00:00 2001
From: Matthias Schmidt <gravatronics@live.com>
Date: Sun, 13 Jan 2019 10:54:16 +0100
Subject: [PATCH] Move form field immutability to separate interface

And add immutability support for some additional fields.

See #2509
---
 com.woltlab.wcf/templates/__iconFormField.tpl | 44 ++++++++++---------
 .../__multipleSelectionFormField.tpl          | 10 ++++-
 .../templates/__singleSelectionFormField.tpl  | 15 ++++++-
 .../files/acp/templates/__iconFormField.tpl   | 44 ++++++++++---------
 .../__multipleSelectionFormField.tpl          | 10 ++++-
 .../templates/__singleSelectionFormField.tpl  | 15 ++++++-
 .../builder/field/AbstractFormField.class.php | 22 ----------
 .../field/AbstractNumericFormField.class.php  |  3 +-
 .../builder/field/BooleanFormField.class.php  |  4 +-
 .../builder/field/DateFormField.class.php     |  4 +-
 .../form/builder/field/IFormField.class.php   | 16 -------
 .../field/IImmutableFormField.class.php       | 29 ++++++++++++
 .../builder/field/IconFormField.class.php     |  4 +-
 .../builder/field/ItemListFormField.class.php |  4 +-
 .../MultipleSelectionFormField.class.php      |  3 +-
 .../field/RadioButtonFormField.class.php      |  3 +-
 .../field/SingleSelectionFormField.class.php  |  3 +-
 .../field/TImmutableFormField.class.php       | 41 +++++++++++++++++
 .../builder/field/TextFormField.class.php     |  3 +-
 .../field/user/UserFormField.class.php        |  5 ++-
 .../field/user/UsernameFormField.class.php    |  5 ++-
 21 files changed, 190 insertions(+), 97 deletions(-)
 create mode 100644 wcfsetup/install/files/lib/system/form/builder/field/IImmutableFormField.class.php
 create mode 100644 wcfsetup/install/files/lib/system/form/builder/field/TImmutableFormField.class.php

diff --git a/com.woltlab.wcf/templates/__iconFormField.tpl b/com.woltlab.wcf/templates/__iconFormField.tpl
index 033ea6b609..fe3cecf0a4 100644
--- a/com.woltlab.wcf/templates/__iconFormField.tpl
+++ b/com.woltlab.wcf/templates/__iconFormField.tpl
@@ -1,28 +1,32 @@
 {include file='__formFieldHeader'}
 
 <span{if $field->getValue()} class="icon icon64 fa-{$field->getValue()}"{/if} id="{@$field->getPrefixedId()}_icon"></span>
-<a href="#" class="button small" id="{@$field->getPrefixedId()}_openIconDialog">{lang}wcf.global.button.edit{/lang}</a>
-<input type="hidden" id="{@$field->getPrefixedId()}" name="{@$field->getPrefixedId()}" value="{$field->getValue()}">
-
-{if $__iconFormFieldIncludeJavaScript}
-	{include file='fontAwesomeJavaScript'}
+{if !$field->isImmutable()}
+	<a href="#" class="button small" id="{@$field->getPrefixedId()}_openIconDialog">{lang}wcf.global.button.edit{/lang}</a>
 {/if}
+<input type="hidden" id="{@$field->getPrefixedId()}" name="{@$field->getPrefixedId()}" value="{$field->getValue()}">
 
-<script data-relocate="true">
-	require(['WoltLabSuite/Core/Ui/Style/FontAwesome'], function(UiStyleFontAwesome) {
-		var button = elById('{@$field->getPrefixedId()}_openIconDialog');
-		var icon = elById('{@$field->getPrefixedId()}_icon');
-		var input = elById('{@$field->getPrefixedId()}');
-		
-		var callback = function(iconName) {
-			icon.className = 'icon icon64 fa-' + iconName;
-			input.value = iconName;
-		};
-		
-		button.addEventListener('click', function() {
-			UiStyleFontAwesome.open(callback);
+{if !$field->isImmutable()}
+	{if $__iconFormFieldIncludeJavaScript}
+		{include file='fontAwesomeJavaScript'}
+	{/if}
+	
+	<script data-relocate="true">
+		require(['WoltLabSuite/Core/Ui/Style/FontAwesome'], function(UiStyleFontAwesome) {
+			var button = elById('{@$field->getPrefixedId()}_openIconDialog');
+			var icon = elById('{@$field->getPrefixedId()}_icon');
+			var input = elById('{@$field->getPrefixedId()}');
+			
+			var callback = function(iconName) {
+				icon.className = 'icon icon64 fa-' + iconName;
+				input.value = iconName;
+			};
+			
+			button.addEventListener('click', function() {
+				UiStyleFontAwesome.open(callback);
+			});
 		});
-	});
-</script>
+	</script>
+{/if}
 
 {include file='__formFieldFooter'}
diff --git a/com.woltlab.wcf/templates/__multipleSelectionFormField.tpl b/com.woltlab.wcf/templates/__multipleSelectionFormField.tpl
index 5f531d6940..8920cbb2e3 100644
--- a/com.woltlab.wcf/templates/__multipleSelectionFormField.tpl
+++ b/com.woltlab.wcf/templates/__multipleSelectionFormField.tpl
@@ -20,12 +20,18 @@
 	<ul class="scrollableCheckboxList" id="{@$field->getPrefixedId()}_list">
 		{foreach from=$field->getNestedOptions() item=__fieldNestedOption}
 			<li{if $__fieldNestedOption[depth] > 0} style="padding-left: {$__fieldNestedOption[depth]*20}px"{/if}>
-				<label><input type="checkbox" name="{@$field->getPrefixedId()}[]" value="{$__fieldNestedOption[value]}"{if $field->getValue() !== null && $__fieldNestedOption[value]|in_array:$field->getValue()} checked{/if}> {@$__fieldNestedOption[label]}</label>
+				<label><input {*
+						*}type="checkbox" {*
+						*}name="{@$field->getPrefixedId()}[]" {*
+						*}value="{$__fieldNestedOption[value]}"{*
+						*}{if $field->getValue() !== null && $__fieldNestedOption[value]|in_array:$field->getValue()} checked{/if}{*
+						*}{if $field->isImmutable()} disabled{/if}{*
+					*}> {@$__fieldNestedOption[label]}</label>
 			</li>
 		{/foreach}
 	</ul>
 {else}
-	{htmlCheckboxes options=$field->getOptions() name=$field->getPrefixedId() selected=$field->getValue() disableEncoding=true}
+	{htmlCheckboxes options=$field->getOptions() name=$field->getPrefixedId() selected=$field->getValue() disabled=$field->isImmutable() disableEncoding=true}
 {/if}
 
 {include file='__formFieldFooter'}
diff --git a/com.woltlab.wcf/templates/__singleSelectionFormField.tpl b/com.woltlab.wcf/templates/__singleSelectionFormField.tpl
index e54da20a28..f772ab7b03 100644
--- a/com.woltlab.wcf/templates/__singleSelectionFormField.tpl
+++ b/com.woltlab.wcf/templates/__singleSelectionFormField.tpl
@@ -20,14 +20,25 @@
 	<ul class="scrollableCheckboxList" id="{@$field->getPrefixedId()}_list">
 		{foreach from=$field->getNestedOptions() item=__fieldNestedOption}
 			<li{if $__fieldNestedOption[depth] > 0} style="padding-left: {$__fieldNestedOption[depth]*20}px"{/if}>
-				<label><input type="radio" name="{@$field->getPrefixedId()}" value="{$__fieldNestedOption[value]}"{if $field->getValue() == $__fieldNestedOption[value]} checked{/if}> {@$__fieldNestedOption[label]}</label>
+				<label><input {*
+						*}type="radio" {*
+						*}name="{@$field->getPrefixedId()}" {*
+						*}value="{$__fieldNestedOption[value]}"{*
+						*}{if $field->getValue() == $__fieldNestedOption[value]} checked{/if}{*
+						*}{if $field->isImmutable()} disabled{/if}{*
+					*}> {@$__fieldNestedOption[label]}</label>
 			</li>
 		{/foreach}
 	</ul>
 {else}
 	<select id="{@$field->getPrefixedId()}" name="{@$field->getPrefixedId()}">
 		{foreach from=$field->getNestedOptions() item=__fieldNestedOption}
-			<option name="{@$field->getPrefixedId()}" value="{$__fieldNestedOption[value]}"{if $field->getValue() == $__fieldNestedOption[value]} selected{/if}>{@'&nbsp;'|str_repeat:$__fieldNestedOption[depth] * 4}{@$__fieldNestedOption[label]}</option>
+			<option {*
+				*}name="{@$field->getPrefixedId()}" {*
+				*}value="{$__fieldNestedOption[value]}"{*
+				*}{if $field->getValue() == $__fieldNestedOption[value]} selected{/if}{*
+				*}{if $field->isImmutable()} disabled{/if}{*
+			*}>{@'&nbsp;'|str_repeat:$__fieldNestedOption[depth] * 4}{@$__fieldNestedOption[label]}</option>
 		{/foreach}
 	</select>
 {/if}
diff --git a/wcfsetup/install/files/acp/templates/__iconFormField.tpl b/wcfsetup/install/files/acp/templates/__iconFormField.tpl
index 033ea6b609..fe3cecf0a4 100644
--- a/wcfsetup/install/files/acp/templates/__iconFormField.tpl
+++ b/wcfsetup/install/files/acp/templates/__iconFormField.tpl
@@ -1,28 +1,32 @@
 {include file='__formFieldHeader'}
 
 <span{if $field->getValue()} class="icon icon64 fa-{$field->getValue()}"{/if} id="{@$field->getPrefixedId()}_icon"></span>
-<a href="#" class="button small" id="{@$field->getPrefixedId()}_openIconDialog">{lang}wcf.global.button.edit{/lang}</a>
-<input type="hidden" id="{@$field->getPrefixedId()}" name="{@$field->getPrefixedId()}" value="{$field->getValue()}">
-
-{if $__iconFormFieldIncludeJavaScript}
-	{include file='fontAwesomeJavaScript'}
+{if !$field->isImmutable()}
+	<a href="#" class="button small" id="{@$field->getPrefixedId()}_openIconDialog">{lang}wcf.global.button.edit{/lang}</a>
 {/if}
+<input type="hidden" id="{@$field->getPrefixedId()}" name="{@$field->getPrefixedId()}" value="{$field->getValue()}">
 
-<script data-relocate="true">
-	require(['WoltLabSuite/Core/Ui/Style/FontAwesome'], function(UiStyleFontAwesome) {
-		var button = elById('{@$field->getPrefixedId()}_openIconDialog');
-		var icon = elById('{@$field->getPrefixedId()}_icon');
-		var input = elById('{@$field->getPrefixedId()}');
-		
-		var callback = function(iconName) {
-			icon.className = 'icon icon64 fa-' + iconName;
-			input.value = iconName;
-		};
-		
-		button.addEventListener('click', function() {
-			UiStyleFontAwesome.open(callback);
+{if !$field->isImmutable()}
+	{if $__iconFormFieldIncludeJavaScript}
+		{include file='fontAwesomeJavaScript'}
+	{/if}
+	
+	<script data-relocate="true">
+		require(['WoltLabSuite/Core/Ui/Style/FontAwesome'], function(UiStyleFontAwesome) {
+			var button = elById('{@$field->getPrefixedId()}_openIconDialog');
+			var icon = elById('{@$field->getPrefixedId()}_icon');
+			var input = elById('{@$field->getPrefixedId()}');
+			
+			var callback = function(iconName) {
+				icon.className = 'icon icon64 fa-' + iconName;
+				input.value = iconName;
+			};
+			
+			button.addEventListener('click', function() {
+				UiStyleFontAwesome.open(callback);
+			});
 		});
-	});
-</script>
+	</script>
+{/if}
 
 {include file='__formFieldFooter'}
diff --git a/wcfsetup/install/files/acp/templates/__multipleSelectionFormField.tpl b/wcfsetup/install/files/acp/templates/__multipleSelectionFormField.tpl
index 5f531d6940..8920cbb2e3 100644
--- a/wcfsetup/install/files/acp/templates/__multipleSelectionFormField.tpl
+++ b/wcfsetup/install/files/acp/templates/__multipleSelectionFormField.tpl
@@ -20,12 +20,18 @@
 	<ul class="scrollableCheckboxList" id="{@$field->getPrefixedId()}_list">
 		{foreach from=$field->getNestedOptions() item=__fieldNestedOption}
 			<li{if $__fieldNestedOption[depth] > 0} style="padding-left: {$__fieldNestedOption[depth]*20}px"{/if}>
-				<label><input type="checkbox" name="{@$field->getPrefixedId()}[]" value="{$__fieldNestedOption[value]}"{if $field->getValue() !== null && $__fieldNestedOption[value]|in_array:$field->getValue()} checked{/if}> {@$__fieldNestedOption[label]}</label>
+				<label><input {*
+						*}type="checkbox" {*
+						*}name="{@$field->getPrefixedId()}[]" {*
+						*}value="{$__fieldNestedOption[value]}"{*
+						*}{if $field->getValue() !== null && $__fieldNestedOption[value]|in_array:$field->getValue()} checked{/if}{*
+						*}{if $field->isImmutable()} disabled{/if}{*
+					*}> {@$__fieldNestedOption[label]}</label>
 			</li>
 		{/foreach}
 	</ul>
 {else}
-	{htmlCheckboxes options=$field->getOptions() name=$field->getPrefixedId() selected=$field->getValue() disableEncoding=true}
+	{htmlCheckboxes options=$field->getOptions() name=$field->getPrefixedId() selected=$field->getValue() disabled=$field->isImmutable() disableEncoding=true}
 {/if}
 
 {include file='__formFieldFooter'}
diff --git a/wcfsetup/install/files/acp/templates/__singleSelectionFormField.tpl b/wcfsetup/install/files/acp/templates/__singleSelectionFormField.tpl
index e54da20a28..f772ab7b03 100644
--- a/wcfsetup/install/files/acp/templates/__singleSelectionFormField.tpl
+++ b/wcfsetup/install/files/acp/templates/__singleSelectionFormField.tpl
@@ -20,14 +20,25 @@
 	<ul class="scrollableCheckboxList" id="{@$field->getPrefixedId()}_list">
 		{foreach from=$field->getNestedOptions() item=__fieldNestedOption}
 			<li{if $__fieldNestedOption[depth] > 0} style="padding-left: {$__fieldNestedOption[depth]*20}px"{/if}>
-				<label><input type="radio" name="{@$field->getPrefixedId()}" value="{$__fieldNestedOption[value]}"{if $field->getValue() == $__fieldNestedOption[value]} checked{/if}> {@$__fieldNestedOption[label]}</label>
+				<label><input {*
+						*}type="radio" {*
+						*}name="{@$field->getPrefixedId()}" {*
+						*}value="{$__fieldNestedOption[value]}"{*
+						*}{if $field->getValue() == $__fieldNestedOption[value]} checked{/if}{*
+						*}{if $field->isImmutable()} disabled{/if}{*
+					*}> {@$__fieldNestedOption[label]}</label>
 			</li>
 		{/foreach}
 	</ul>
 {else}
 	<select id="{@$field->getPrefixedId()}" name="{@$field->getPrefixedId()}">
 		{foreach from=$field->getNestedOptions() item=__fieldNestedOption}
-			<option name="{@$field->getPrefixedId()}" value="{$__fieldNestedOption[value]}"{if $field->getValue() == $__fieldNestedOption[value]} selected{/if}>{@'&nbsp;'|str_repeat:$__fieldNestedOption[depth] * 4}{@$__fieldNestedOption[label]}</option>
+			<option {*
+				*}name="{@$field->getPrefixedId()}" {*
+				*}value="{$__fieldNestedOption[value]}"{*
+				*}{if $field->getValue() == $__fieldNestedOption[value]} selected{/if}{*
+				*}{if $field->isImmutable()} disabled{/if}{*
+			*}>{@'&nbsp;'|str_repeat:$__fieldNestedOption[depth] * 4}{@$__fieldNestedOption[label]}</option>
 		{/foreach}
 	</select>
 {/if}
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
index 0bbae157e4..5583b02038 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractFormField.class.php
@@ -27,12 +27,6 @@ abstract class AbstractFormField implements IFormField {
 	 */
 	protected $__autoFocus = false;
 	
-	/**
-	 * `true` if the value of this field is immutable and `false` otherwise
-	 * @var	bool
-	 */
-	protected $__immutable = false;
-	
 	/**
 	 * name of the object property this field represents
 	 * @var	null|string
@@ -179,15 +173,6 @@ abstract class AbstractFormField implements IFormField {
 		return true;
 	}
 	
-	/**
-	 * @inheritDoc
-	 */
-	public function immutable($immutable = true) {
-		$this->__immutable = $immutable;
-		
-		return $this;
-	}
-	
 	/**
 	 * @inheritDoc
 	 */
@@ -195,13 +180,6 @@ abstract class AbstractFormField implements IFormField {
 		return $this->__autoFocus;
 	}
 	
-	/**
-	 * @inheritDoc
-	 */
-	public function isImmutable() {
-		return $this->__immutable;
-	}
-	
 	/**
 	 * @inheritDoc
 	 */
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/AbstractNumericFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/AbstractNumericFormField.class.php
index d0ac5b883f..8e4837f44b 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/AbstractNumericFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/AbstractNumericFormField.class.php
@@ -11,7 +11,8 @@ use wcf\system\form\builder\field\validation\FormFieldValidationError;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-abstract class AbstractNumericFormField extends AbstractFormField implements IMaximumFormField, IMinimumFormField, INullableFormField, IPlaceholderFormField, ISuffixedFormField {
+abstract class AbstractNumericFormField extends AbstractFormField implements IImmutableFormField, IMaximumFormField, IMinimumFormField, INullableFormField, IPlaceholderFormField, ISuffixedFormField {
+	use TImmutableFormField;
 	use TMaximumFormField;
 	use TMinimumFormField;
 	use TNullableFormField;
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/BooleanFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/BooleanFormField.class.php
index df3095f55c..b277eea8fd 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/BooleanFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/BooleanFormField.class.php
@@ -11,7 +11,9 @@ use wcf\system\form\builder\field\validation\FormFieldValidationError;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class BooleanFormField extends AbstractFormField {
+class BooleanFormField extends AbstractFormField implements IImmutableFormField {
+	use TImmutableFormField;
+	
 	/**
 	 * @inheritDoc
 	 */
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/DateFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/DateFormField.class.php
index c8e599a11c..bee9fb5cf0 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/DateFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/DateFormField.class.php
@@ -11,7 +11,9 @@ use wcf\system\form\builder\field\validation\FormFieldValidationError;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class DateFormField extends AbstractFormField {
+class DateFormField extends AbstractFormField implements IImmutableFormField {
+	use TImmutableFormField;
+	
 	/**
 	 * date time format of the save value
 	 * @var	string
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
index 0273d144d4..be0f98a303 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IFormField.class.php
@@ -107,14 +107,6 @@ interface IFormField extends IFormChildNode, IFormElement {
 	 */
 	public function hasSaveValue();
 	
-	/**
-	 * Sets whether the value of this field is immutable and returns this field.
-	 * 
-	 * @param	bool		$immutable	determines if field value is immutable
-	 * @return	static				this field
-	 */
-	public function immutable($immutable = true);
-	
 	/**
 	 * Returns `true` if this field is auto-focused and returns `false` otherwise.
 	 * By default, fields are not auto-focused.
@@ -123,14 +115,6 @@ interface IFormField extends IFormChildNode, IFormElement {
 	 */
 	public function isAutoFocused();
 	
-	/**
-	 * Returns `true` if the value of this field is immutable and returns `false`
-	 * otherwise. By default, fields are mutable.
-	 * 
-	 * @return	bool
-	 */
-	public function isImmutable();
-	
 	/**
 	 * Returns `true` if this field has to be filled out and returns `false` otherwise.
 	 * By default, fields do not have to be filled out.
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IImmutableFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IImmutableFormField.class.php
new file mode 100644
index 0000000000..211283cc02
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IImmutableFormField.class.php
@@ -0,0 +1,29 @@
+<?php
+namespace wcf\system\form\builder\field;
+
+/**
+ * Represents a form field that can be set as immutable.
+ * 
+ * @author	Matthias Schmidt
+ * @copyright	2001-2018 WoltLab GmbH
+ * @license	GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package	WoltLabSuite\Core\System\Form\Builder\Field
+ * @since	5.2
+ */
+interface IImmutableFormField {
+	/**
+	 * Sets whether the value of this field is immutable and returns this field.
+	 * 
+	 * @param	bool		$immutable	determines if field value is immutable
+	 * @return	static				this field
+	 */
+	public function immutable($immutable = true);
+	
+	/**
+	 * Returns `true` if the value of this field is immutable and returns `false`
+	 * otherwise. By default, fields are mutable.
+	 * 
+	 * @return	bool
+	 */
+	public function isImmutable();
+}
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/IconFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/IconFormField.class.php
index ceea8cbf99..88d178885b 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/IconFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/IconFormField.class.php
@@ -12,7 +12,9 @@ use wcf\system\style\StyleHandler;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class IconFormField extends AbstractFormField {
+class IconFormField extends AbstractFormField implements IImmutableFormField {
+	use TImmutableFormField;
+	
 	/**
 	 * @inheritDoc
 	 */
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/ItemListFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/ItemListFormField.class.php
index 8792186158..978e2aa8bb 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/ItemListFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/ItemListFormField.class.php
@@ -14,7 +14,9 @@ use wcf\util\ArrayUtil;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class ItemListFormField extends AbstractFormField {
+class ItemListFormField extends AbstractFormField implements IImmutableFormField {
+	use TImmutableFormField;
+	
 	/**
 	 * type of the returned save value (see `SAVE_VALUE_TYPE_*` constants)
 	 * @var	string
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/MultipleSelectionFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/MultipleSelectionFormField.class.php
index abc58ae2fb..06aa215e9d 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/MultipleSelectionFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/MultipleSelectionFormField.class.php
@@ -11,8 +11,9 @@ use wcf\system\form\builder\field\validation\FormFieldValidationError;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class MultipleSelectionFormField extends AbstractFormField implements IFilterableSelectionFormField, INullableFormField {
+class MultipleSelectionFormField extends AbstractFormField implements IFilterableSelectionFormField, IImmutableFormField, INullableFormField {
 	use TFilterableSelectionFormField;
+	use TImmutableFormField;
 	use TNullableFormField;
 	
 	/**
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/RadioButtonFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/RadioButtonFormField.class.php
index 2a982b4e68..ca211a5fdd 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/RadioButtonFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/RadioButtonFormField.class.php
@@ -11,7 +11,8 @@ use wcf\system\form\builder\field\validation\FormFieldValidationError;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class RadioButtonFormField extends AbstractFormField implements ISelectionFormField {
+class RadioButtonFormField extends AbstractFormField implements IImmutableFormField, ISelectionFormField {
+	use TImmutableFormField;
 	use TSelectionFormField;
 	
 	/**
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/SingleSelectionFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/SingleSelectionFormField.class.php
index 5e5e5be7f1..82c73ac70d 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/SingleSelectionFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/SingleSelectionFormField.class.php
@@ -11,7 +11,8 @@ use wcf\system\form\builder\field\validation\FormFieldValidationError;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class SingleSelectionFormField extends AbstractFormField implements IFilterableSelectionFormField, INullableFormField {
+class SingleSelectionFormField extends AbstractFormField implements IImmutableFormField, IFilterableSelectionFormField, INullableFormField {
+	use TImmutableFormField;
 	use TFilterableSelectionFormField;
 	use TNullableFormField;
 	
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/TImmutableFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/TImmutableFormField.class.php
new file mode 100644
index 0000000000..e93c5d279c
--- /dev/null
+++ b/wcfsetup/install/files/lib/system/form/builder/field/TImmutableFormField.class.php
@@ -0,0 +1,41 @@
+<?php
+namespace wcf\system\form\builder\field;
+
+/**
+ * Provides default implementations of `IImmutableFormField` methods.
+ * 
+ * @author	Matthias Schmidt
+ * @copyright	2001-2018 WoltLab GmbH
+ * @license	GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
+ * @package	WoltLabSuite\Core\System\Form\Builder\Field
+ * @since	5.2
+ */
+trait TImmutableFormField {
+	/**
+	 * `true` if the value of this field is immutable and `false` otherwise
+	 * @var	bool
+	 */
+	protected $__immutable = false;
+
+	/**
+	 * Sets whether the value of this field is immutable and returns this field.
+	 * 
+	 * @param	bool		$immutable	determines if field value is immutable
+	 * @return	static				this field
+	 */
+	public function immutable($immutable = true) {
+		$this->__immutable = $immutable;
+		
+		return $this;
+	}
+	
+	/**
+	 * Returns `true` if the value of this field is immutable and returns `false`
+	 * otherwise. By default, fields are mutable.
+	 * 
+	 * @return	bool
+	 */
+	public function isImmutable() {
+		return $this->__immutable;
+	}
+}
\ No newline at end of file
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/TextFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/TextFormField.class.php
index db99e85110..ab303eb3cb 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/TextFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/TextFormField.class.php
@@ -13,7 +13,8 @@ use wcf\system\language\LanguageFactory;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field
  * @since	5.2
  */
-class TextFormField extends AbstractFormField implements II18nFormField, IMaximumLengthFormField, IMinimumLengthFormField, IPlaceholderFormField {
+class TextFormField extends AbstractFormField implements II18nFormField, IImmutableFormField, IMaximumLengthFormField, IMinimumLengthFormField, IPlaceholderFormField {
+	use TImmutableFormField;
 	use TI18nFormField {
 		validate as protected i18nValidate;
 	}
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php
index 12b1b0d46a..18f67e8f55 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/user/UserFormField.class.php
@@ -2,8 +2,10 @@
 namespace wcf\system\form\builder\field\user;
 use wcf\data\user\UserProfile;
 use wcf\system\form\builder\field\AbstractFormField;
+use wcf\system\form\builder\field\IImmutableFormField;
 use wcf\system\form\builder\field\IMultipleFormField;
 use wcf\system\form\builder\field\INullableFormField;
+use wcf\system\form\builder\field\TImmutableFormField;
 use wcf\system\form\builder\field\TMultipleFormField;
 use wcf\system\form\builder\field\TNullableFormField;
 use wcf\system\form\builder\field\validation\FormFieldValidationError;
@@ -19,7 +21,8 @@ use wcf\util\StringUtil;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field\User
  * @since	5.2
  */
-class UserFormField extends AbstractFormField implements IMultipleFormField, INullableFormField {
+class UserFormField extends AbstractFormField implements IImmutableFormField, IMultipleFormField, INullableFormField {
+	use TImmutableFormField;
 	use TMultipleFormField;
 	use TNullableFormField;
 	
diff --git a/wcfsetup/install/files/lib/system/form/builder/field/user/UsernameFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/user/UsernameFormField.class.php
index 8a55626555..8e2b298a82 100644
--- a/wcfsetup/install/files/lib/system/form/builder/field/user/UsernameFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/user/UsernameFormField.class.php
@@ -1,10 +1,12 @@
 <?php
 namespace wcf\system\form\builder\field\user;
 use wcf\system\form\builder\field\AbstractFormField;
+use wcf\system\form\builder\field\IImmutableFormField;
 use wcf\system\form\builder\field\IMaximumLengthFormField;
 use wcf\system\form\builder\field\IMinimumLengthFormField;
 use wcf\system\form\builder\field\INullableFormField;
 use wcf\system\form\builder\field\IPlaceholderFormField;
+use wcf\system\form\builder\field\TImmutableFormField;
 use wcf\system\form\builder\field\TMaximumLengthFormField;
 use wcf\system\form\builder\field\TMinimumLengthFormField;
 use wcf\system\form\builder\field\TNullableFormField;
@@ -23,7 +25,8 @@ use wcf\util\UserUtil;
  * @package	WoltLabSuite\Core\System\Form\Builder\Field\User
  * @since	5.2
  */
-class UsernameFormField extends AbstractFormField implements IMaximumLengthFormField, IMinimumLengthFormField, INullableFormField, IPlaceholderFormField {
+class UsernameFormField extends AbstractFormField implements IImmutableFormField, IMaximumLengthFormField, IMinimumLengthFormField, INullableFormField, IPlaceholderFormField {
+	use TImmutableFormField;
 	use TMaximumLengthFormField;
 	use TMinimumLengthFormField;
 	use TNullableFormField;
-- 
2.20.1