Update ProcessPageEdit to enable removal of system status when superuser in advanced mode (though I don't recommend using it unless you are trying to fix something that's broken), plus make a couple more status options available to superuser in advanced mode. Also some other unrelated and minor optimizations in this module.

wire/modules/Process/ProcessPageEdit/ProcessPageEdit.module

@@ -8,7 +8,7 @@
  * For more details about how Process modules work, please see: 
  * /wire/core/Process.php 
  * 
- * ProcessWire 3.x, Copyright 2018 by Ryan Cramer
+ * ProcessWire 3.x, Copyright 2021 by Ryan Cramer
  * https://processwire.com
  * 
  * @property string $noticeUnknown
@@ -54,7 +54,7 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		return array(
 			'title' => 'Page Edit',
 			'summary' => 'Edit a Page',
-			'version' => 109,
+			'version' => 110,
 			'permanent' => true,
 			'permission' => 'page-edit',
 			'icon' => 'edit',
@@ -345,8 +345,13 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		$this->set('viewAction', 'this');
 		return parent::__construct();
 	}
-	
+
+	/**
+	 * Wired to API
+	 * 
+	 */
 	public function wired() {
+		parent::wired();
 		if($this->wire('process') instanceof WirePageEditor) {
 			// keep existing process, which may be building on top of this one
 		} else {
@@ -437,7 +442,7 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		if($context) $this->requestContext = $this->sanitizer->name($context);
 	
 		// optional language GET var
-		$languages = $this->wire('languages');
+		$languages = $this->wire()->languages;
 		if($languages) {
 			$this->hasLanguagePageNames = $this->modules->isInstalled('LanguageSupportPageNames');
 			if($this->hasLanguagePageNames) {
@@ -476,40 +481,35 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 	protected function ___loadPage($id) {
 	
 		/** @var Page|NullPage $page */
-		$page = $this->wire('pages')->get((int) $id); 
+		$page = $this->wire()->pages->get((int) $id);
 		
 		if($page instanceof NullPage) {
 			throw new WireException($this->noticeUnknown); // page doesn't exist
 		}
 
 		$editable = $page->editable();
-	
-		/** @var User $user */
-		$user = $this->user;
-		
-		/** @var Config $config */
-		$config = $this->config;
-		
-		/** @var Config $config */
-		$input = $this->input; 
 		
 		if($page instanceof User) {
 			// special case when page is a User
+			$userAdmin = $this->user->hasPermission('user-admin');
 			
-			$userAdmin = $user->hasPermission('user-admin');
-			$field = $input->get('field') ? $this->wire('fields')->get($input->get->fieldName('field')) : null;
-			
-			if($userAdmin && $this->wire('process') != 'ProcessUser') {
+			if($userAdmin && $this->wire()->process != 'ProcessUser') {
 				// only allow user pages to be edited from the access section (at least for non-superusers)
-				$this->session->redirect($config->urls->admin . 'access/users/edit/?id=' . $page->id);
+				$this->session->redirect($this->config->urls->admin . 'access/users/edit/?id=' . $page->id);
+			}
 				
-			} else if(!$userAdmin && $page->id === $user->id && $field && $config->ajax) {
-				// user is editing themself and we're responding to an ajax request for a field
-				/** @var PagePermissions $pagePermissions */
-				$pagePermissions = $this->modules->get('PagePermissions');
-				$editable = $pagePermissions->userFieldEditable($field); 
-				// prevent a later potential redirect to user editor
-				if($editable) $this->setEditor = false;
+			if(!$userAdmin && $page->id === $this->user->id && $this->config->ajax) {
+				// user that lacks user-admin permission editing themself during ajax request
+				$fieldName = $this->input->get->fieldName('field');
+				$field = $fieldName ? $this->wire()->fields->get($fieldName) : null;
+				if($field instanceof Field) {
+					// respond to ajax request for field that is editable
+					/** @var PagePermissions $pagePermissions */
+					$pagePermissions = $this->modules->get('PagePermissions');
+					$editable = $pagePermissions->userFieldEditable($field);
+					// prevent a later potential redirect to user editor
+					if($editable) $this->setEditor = false;
+				}
 			}
 		}
 		
@@ -633,7 +633,8 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 			$out .= "</ul>";
 		}
 
-		$out .= "<scr" . "ipt>initPageEditForm();</script>"; // ends up being slightly faster than ready() (or at least appears that way)
+		$func = 'initPageEditForm();'; // to prevent IDE from flagging as unknown function
+		$out .= "<scr" . "ipt>$func</script>"; // ends up being slightly faster than ready() (or at least appears that way)
 		
 		return $out; 
 	}
@@ -665,6 +666,7 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		if($this->requestModal) return array();
 		
 		$viewable = $this->page->viewable();
+		$process = $this->wire()->process;
 		$actions = array();
 		
 		$actions['exit'] = array(
@@ -680,9 +682,8 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 			'label' => $this->_('%s + View'),
 			'class' => '',
 		);
-		
-		if($this->wire('process') == $this && $this->page->id > 1) {
-			
+	
+		if("$process" === "$this" && $this->page->id > 1) {
 			$parent = $this->page->parent();
 			if($parent->addable()) $actions['add'] = array(
 				'value' => 'add',
@@ -1459,14 +1460,10 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 	 */
 	protected function buildFormPrevPaths() {
 	
-		/** @var WireInput $input */
-		$input = $this->wire('input');
-		/** @var Modules $modules */
-		$modules = $this->wire('modules');
-		/** @var Sanitizer $sanitizer */
-		$sanitizer = $this->wire('sanitizer');
-		/** @var Languages|null $languages */
-		$languages = $this->wire('languages');
+		$input = $this->input;
+		$modules = $this->modules;
+		$sanitizer = $this->sanitizer;
+		$languages = $this->wire()->languages;
 		
 		if($this->isPost && $input->post('_prevpath_add') === null) return null;
 		if(!$modules->isInstalled('PagePathHistory')) return null;
@@ -1697,34 +1694,14 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 	protected function buildFormStatus() {
 		
 		$status = (int) $this->page->status;
-		$statuses = array(); 
 		$debug = $this->config->debug;
-		$advanced = $this->config->advanced;
+		$statuses = $this->getAllowedStatuses();
 		
 		/** @var InputfieldCheckboxes $field */
 		$field = $this->modules->get('InputfieldCheckboxes');
 		$field->attr('name', 'status');
 		$field->icon = 'sliders';
 
-		if(!$this->page->template->noUnpublish && $this->page->publishable()) {
-			$statuses[Page::statusUnpublished] = $this->_('Unpublished: Not visible on site'); // Settings: Unpublished status checkbox label
-		}
-		if($this->user->hasPermission('page-hide', $this->page)) {
-			$statuses[Page::statusHidden] = $this->_('Hidden: Excluded from lists and searches'); // Settings: Hidden status checkbox label
-		}
-		if($this->user->hasPermission('page-lock', $this->page)) {
-			$statuses[Page::statusLocked] = $this->_('Locked: Not editable'); // Settings: Locked status checkbox label
-		}
-			
-		if($this->user->isSuperuser()) {
-			$statuses[Page::statusUnique] = sprintf($this->_('Unique: Require page name “%s” to be globally unique'), $this->page->name) . 
-				($this->wire('languages') ?  ' ' . $this->_('(in default language only)') : '');
-			if($advanced) {
-				$statuses[Page::statusSystemID] = "System: Non-deleteable and locked ID (status not removeable via API)";
-				$statuses[Page::statusSystem] = "System: Non-deleteable and locked ID, name, template, parent (status not removeable via API)";
-			}
-		}
-
 		$value = array();
 		
 		foreach($statuses as $s => $label) {
@@ -1803,7 +1780,7 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 	
 		if(!$this->page->isTrash()) return false;
 		if(!$this->page->restorable()) return false;
-		$info = $this->wire('pages')->trasher()->getRestoreInfo($this->page);
+		$info = $this->wire()->pages->trasher()->getRestoreInfo($this->page);
 		if(!$info['restorable']) return false;
 		
 		/** @var InputfieldWrapper $wrapper */
@@ -2195,7 +2172,7 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 			$this->page->setQuietly('_forceAddStatus', 0);
 		}
 
-		$languages = $this->wire('languages'); 
+		$languages = $this->wire()->languages; 
 		$errorAction = (int) $this->page->template->errorAction;
 
 		foreach($form as $inputfield) {
@@ -2383,34 +2360,30 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 	 */
 	protected function processInputStatus(Inputfield $inputfield) {
 
-		$status = $inputfield->value; 
+		$inputStatusFlags = $inputfield->val(); 
+		if(!is_array($inputStatusFlags)) $inputStatusFlags = array();
+		foreach($inputStatusFlags as $k => $v) $inputStatusFlags[$k] = (int) $v;
+	
+		$allowedStatusFlags = array_keys($this->getAllowedStatuses());
+		$statusLabels = array_flip(Page::getStatuses());
 		$value = $this->page->status; 
 
-		if(!is_array($status)) $status = array();
-
-		$statusFlags = array();
-		if($this->user->hasPermission('page-hide', $this->page)) $statusFlags[] = Page::statusHidden; 
-		if($this->page->publishable()) $statusFlags[] = Page::statusUnpublished; 
-		if($this->user->hasPermission('page-lock', $this->page)) $statusFlags[] = Page::statusLocked;
-
-		if($this->user->isSuperuser()) {
-			$statusFlags[] = Page::statusUnique;
-			if($this->config->advanced) {
-				$statusFlags[] = Page::statusSystemID;
-				$statusFlags[] = Page::statusSystem;
-			}
-		}
-
-		foreach($statusFlags as $flag) {
-			if(in_array($flag, $status)) {
-				if(!($value & $flag)) $value = $value | $flag; 
-
+		foreach($allowedStatusFlags as $flag) {
+			if(in_array($flag, $inputStatusFlags, true)) {
+				if($value & $flag) {
+					// already has flag
+				} else {
+					$value = $value | $flag; // add status
+					$this->message(sprintf($this->_('Added status: %s'), $statusLabels[$flag]), Notice::debug);
+				}
 			} else if($value & $flag) {
-				$value = $value & ~$flag; 
+				$value = $value & ~$flag; // remove flag
+				$this->message(sprintf($this->_('Removed status: %s'), $statusLabels[$flag]), Notice::debug);
 			}
 		}
-
+		
 		$this->page->status = $value; 
+		
 		return true; 
 	}
 
@@ -2500,6 +2473,7 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		if(!$this->ajaxEditable($page)) throw new WirePermissionException($this->noticeNoAccess);
 		$this->session->CSRF->validate(); // throws exception when invalid
 
+		/** @var InputfieldWrapper $form */
 		$form = $this->wire(new InputfieldWrapper());
 		$form->useDependencies = false;
 		$keys = array();
@@ -2963,6 +2937,61 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		return $this->tabs; 
 	}
 
+	/**
+	 * Get allowed page statuses
+	 *
+	 * @return array Array of [ statusFlagInteger => 'Status flag label' ]
+	 * @since 3.0.181
+	 *
+	 */
+	public function getAllowedStatuses() {
+
+		$page = $this->page;
+		$config = $this->wire()->config;
+		$statuses = array();
+		$superuser = $this->user->isSuperuser();
+
+		if(!$this->page->template->noUnpublish && $this->page->publishable()) {
+			$statuses[Page::statusUnpublished] = $this->_('Unpublished: Not visible on site'); // Settings: Unpublished status checkbox label
+		}
+
+		if($this->user->hasPermission('page-hide', $this->page)) {
+			$statuses[Page::statusHidden] = $this->_('Hidden: Excluded from lists and searches'); // Settings: Hidden status checkbox label
+		}
+
+		if($this->user->hasPermission('page-lock', $this->page)) {
+			$statuses[Page::statusLocked] = $this->_('Locked: Not editable'); // Settings: Locked status checkbox label
+		}
+
+		if($superuser) {
+			$uniqueNote = ($this->wire('languages') ? ' ' . $this->_('(in default language only)') : '');
+			$statuses[Page::statusUnique] = sprintf($this->_('Unique: Require page name “%s” to be globally unique'), $this->page->name) . $uniqueNote;
+		}
+
+		if($superuser && $config->advanced) {
+			// additional statuses available to superuser in advanced mode
+			$hasSystem = $page->hasStatus(Page::statusSystem) || $page->hasStatus(Page::statusSystemID) || $page->hasStatus(Page::statusSystemOverride);
+			$statuses[Page::statusSystem] = "System: Non-deleteable and locked ID, name, template, parent (status not removeable without override)";
+			$statuses[Page::statusSystemID] = "System ID: Non-deleteable and locked ID (status not removeable without override)";
+			if($hasSystem) $statuses[Page::statusSystemOverride] = "System Override: Override (must be added temporarily in its own save before system status can be removed)";
+			$statuses[Page::statusDraft] = "Draft: Page has a separate draft version";
+			$statuses[Page::statusOn] = "On: Internal toggle when combined with other statuses (only for specific cases, otherwise ignored)";
+			/*
+			 * Additional statuses that are possible but shouldn't be editable (uncomment temporarily if needed)
+			 * 
+			 * $statuses[Page::statusTemp] = "Temp: Unpublished page more than 1 day old may be automatically deleted";
+			 * $statuses[Page::statusFlagged] = "Flagged: Page is flagged as incomplete, needing review, or having some issue";
+			 * $statuses[Page::statusTrash] = "Internal trash: Indicates that page is in the trash";
+			 * $statuses[Page::statusReserved] = "Internal-reserved: Status reserved for future use";
+			 * $statuses[Page::statusInternal] = "Internal-internal: Status for internal or future use";
+			 * 
+			 */
+		}
+
+		return $statuses;
+	}
+
+
 	/**
 	 * Get PageBookmarks array
 	 * 
@@ -3147,11 +3176,16 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 	 * 
 	 */
 	public function getModuleConfigInputfields(array $data) {
-		
+	
+		$config = $this->wire()->config;
+		$pages = $this->wire()->pages;
+		$modules = $this->wire()->modules;
 		$inputfields = new InputfieldWrapper();
-		$this->wire($inputfields); 
 		
-		$f = $this->wire('modules')->get('InputfieldRadios');
+		$this->wire($inputfields); 
+	
+		/** @var InputfieldRadios $f */
+		$f = $modules->get('InputfieldRadios');
 		$f->name = 'viewAction'; 
 		$f->label = $this->_('Default "view" location/action'); 
 		$f->description = $this->_('The default type of action used when the "view" tab is clicked on in the page editor.');
@@ -3161,7 +3195,8 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 			$f->addOption($name, $label);
 		}
 
-		$configData = $this->wire('config')->pageEdit;
+		/** @var array $configData */
+		$configData = $config->pageEdit;
 		if(isset($data['viewAction'])) {
 			$f->attr('value', $data['viewAction']);
 		} else if(is_array($configData) && !empty($configData['viewNew'])) {
@@ -3174,8 +3209,8 @@ class ProcessPageEdit extends Process implements WirePageEditor, ConfigurableMod
 		
 		$bookmarks = $this->getPageBookmarks();
 		$bookmarks->addConfigInputfields($inputfields);
-		$admin = $this->wire('pages')->get($this->wire('config')->adminRootPageID);
-		$page = $this->wire('pages')->get($admin->path . 'page/edit/');
+		$admin = $pages->get($config->adminRootPageID);
+		$page = $pages->get($admin->path . 'page/edit/');
 		$bookmarks->checkProcessPage($page);
 		
 		return $inputfields;