From 0edd963f21bcbfe3f5628d76ff94a281501a9a96 Mon Sep 17 00:00:00 2001
From: Jan-Hendrik Willms <tleilax+studip@gmail.com>
Date: Wed, 11 Feb 2026 13:58:37 +0100
Subject: delete theme asset upon theme deletion, allow activation regardless
 of other themes state and some small touchups, fixes #6244

---
 lib/classes/JsonApi/Routes/Themes/ThemesUpdate.php | 14 +++++++++-----
 lib/classes/PageLayout.php                         |  2 +-
 lib/models/Theme.php                               | 18 +++++++++++++++---
 public/assets.php                                  |  2 +-
 4 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/lib/classes/JsonApi/Routes/Themes/ThemesUpdate.php b/lib/classes/JsonApi/Routes/Themes/ThemesUpdate.php
index 751b0d0..c1fcc6b 100644
--- a/lib/classes/JsonApi/Routes/Themes/ThemesUpdate.php
+++ b/lib/classes/JsonApi/Routes/Themes/ThemesUpdate.php
@@ -35,13 +35,17 @@ class ThemesUpdate extends JsonApiController
         if (self::arrayGet($json, 'data.attributes.active') === true) {
             $activeThemes = \Theme::getActiveThemes();
             foreach ($activeThemes as $theme) {
-                if ($theme->id !== $resource->id && $theme->type === $resource->type) {
+                if (
+                    $theme->id !== $resource->id
+                    && $theme->type === $resource->type
+                ) {
                     $theme->active = false;
                     $theme->store();
-                    $resource->active = true;
-                    $resource->store();
                 }
             }
+
+            $resource->active = true;
+            $resource->store();
         }
 
         return $this->getContentResponse($resource);
@@ -77,10 +81,10 @@ class ThemesUpdate extends JsonApiController
                 $resource->$sormKey = $val;
             }
         }
-        
+
         $resource->store();
 
         return $resource;
     }
 
-}
\ No newline at end of file
+}
diff --git a/lib/classes/PageLayout.php b/lib/classes/PageLayout.php
index c529fa6..17ddf76 100644
--- a/lib/classes/PageLayout.php
+++ b/lib/classes/PageLayout.php
@@ -147,7 +147,7 @@ class PageLayout
             $old_base = URLHelper::setBaseURL($GLOBALS['ABSOLUTE_URI_STUDIP']);
             self::addHeadElement('link', [
                 'rel' => 'stylesheet',
-                'href' => Theme::getDownloadURL(),
+                'href' => URLHelper::getLink(Theme::getDownloadURL(), [], true),
             ]);
             URLHelper::setBaseURL($old_base);
         } catch (Exception) {
diff --git a/lib/models/Theme.php b/lib/models/Theme.php
index 824d8cd..852dc42 100644
--- a/lib/models/Theme.php
+++ b/lib/models/Theme.php
@@ -67,8 +67,13 @@
                     && $theme->isFieldDirty('values')
                 )
             ) {
-                self::loadActiveThemes(true);
-                self::getThemeAsset()->writeContent(self::getActiveCSS());
+                self::regenerateCSS();
+            }
+        };
+
+        $config['registered_callbacks']['after_delete'][] = function (Theme $theme): void {
+            if ($theme->active) {
+                self::regenerateCSS();
             }
         };
 
@@ -105,12 +110,19 @@
     public static function getDownloadURL(): string
     {
         $asset = self::getThemeAsset();
-        return URLHelper::getLink(
+        return URLHelper::getURL(
             "assets.php/css/{$asset->id}#{$asset->filename}",
             ['v' => $asset->chdate],
             true
         );
+    }
+
+    private static function regenerateCSS(): void
+    {
+        self::getThemeAsset()->delete();
 
+        self::loadActiveThemes(true);
+        self::getThemeAsset()->writeContent(self::getActiveCSS());
     }
 
     public static function getActiveCSS(): string
diff --git a/public/assets.php b/public/assets.php
index 886886b..d10b6ad 100644
--- a/public/assets.php
+++ b/public/assets.php
@@ -45,7 +45,7 @@ $app->get('/{type:js|css}/{id}', function (ServerRequestInterface $request, Resp
         $response->getBody()->write($asset->getContent());
 
         $response = $response->withHeader('Content-Type', $args['type'] === 'css' ? 'text/css' : 'application/javascript');
-        $response = $response->withHeader('Content-Length', $model->size);
+        $response = $response->withHeader('Content-Length', $model->size ?? 0);
 
         // Store cache information
         if (Studip\ENV !== 'development') {
-- 
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