[FEATURE] Limit elements in Page module with default language and language mode

If the language mode is chosen in the page module and the default
language is selected, only the elements of the default language must be
chosen.

Resolves: #92460
Releases: master
Change-Id: Ieb472967e37d85095d0cdd7c1608c5f48adcfc49
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/65970

Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benni Mack <benni@typo3.org>

typo3/sysext/backend/Classes/Controller/PageLayoutController.php

@@ -264,6 +264,13 @@ class PageLayoutController
             if (isset($this->availableLanguages[0])) {
                 $this->MOD_MENU['language'][0] = $this->availableLanguages[0]->getTitle();
             }
+            // We need to add -1 (all) here so a possible -1 value in &SET['language'] will be respected
+            // by BackendUtility::getModuleData. Actually, this is only relevant if we are dealing with the
+            // "languages" mode, which however can only be determined, after the MOD_SETTINGS have been calculated
+            // by BackendUtility::getModuleData => chicken and egg problem. We therefore remove the -1 item from
+            // the menu again, as soon as we are able to determine the requested mode.
+            // @todo Replace the whole "mode" handling with some more robust solution
+            $this->MOD_MENU['language'][-1] = $this->getLanguageService()->sL('LLL:EXT:core/Resources/Private/Language/locallang_mod_web_list.xlf:multipleLanguages');
         }
         // Initialize the available actions
         $actions = $this->initActions();
@@ -276,6 +283,10 @@ class PageLayoutController
         ) {
             $this->MOD_SETTINGS['tt_content_showHidden'] = 1;
         }
+        if ((int)$this->MOD_SETTINGS['function'] !== 2) {
+            // Remove -1 (all) from the module menu if not "languages" mode
+            unset($this->MOD_MENU['language'][-1]);
+        }
         // Make action menu from available actions
         $this->makeActionMenu($actions);
     }

typo3/sysext/backend/Classes/View/PageLayoutContext.php

@@ -202,6 +202,9 @@ class PageLayoutContext
     public function getLanguagesToShow(): iterable
     {
         $selectedLanguageId = $this->drawingConfiguration->getSelectedLanguageId();
+        if ($selectedLanguageId === -1) {
+            return $this->getSiteLanguages();
+        }
         if ($selectedLanguageId > 0) {
             // A specific language is selected; compose a list of default language plus selected language
             return [
@@ -209,7 +212,7 @@ class PageLayoutContext
                 $this->site->getLanguageById($selectedLanguageId)
             ];
         }
-        return $this->getSiteLanguages();
+        return [$this->site->getDefaultLanguage()];
     }
 
     public function getSiteLanguage(?int $languageId = null): SiteLanguage

typo3/sysext/core/Documentation/Changelog/master/Feature-92460-SplitDefaultFromAllLanguagesInPageModule.rst

+.. include:: ../../Includes.txt
+
+=================================================================
+Feature: #92460 - Split default from all languages in page module
+=================================================================
+
+See :issue:`92460`
+
+Description
+===========
+
+The view "Languages" in the page module allowes to render content elements of
+the default language next to the ones of the selected language.
+
+If the default language is chosen, instead of rendering all content elements
+of all languages, now only the content elements of the default language are
+rendered.
+
+If an editor requires to see all content elements of all languages, the
+option "All languages" can be selected.
+
+
+Impact
+======
+
+Having many languages and many content elements can be a performance issue
+in the page module which is now fixed.
+
+Additionally the language view is now consistent with the column view.
+
+.. index:: Backend, ext:backend