fix(config): refresh a category cache stored with another type

If cache-categories was stored with a type other than mixed or array,
for example set by hand with occ, the typed read throws. Treat that as
a missing cache so it is refreshed instead of breaking the menu and the
settings page.

lib/AppInfo/Application.php

@@ -21,6 +21,7 @@ use OCP\AppFramework\Bootstrap\IRegistrationContext;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\IAppConfig;
+use OCP\ICacheFactory;
 use OCP\IConfig;
 use OCP\INavigationManager;
 use OCP\IRequest;
@@ -62,7 +63,8 @@ class Application extends App implements IBootstrap
                 $c->get(IUserSession::class),
                 $c->get(IAppConfig::class),
                 $c->get(ITimeFactory::class),
-                $c->get(LangRepository::class)
+                $c->get(LangRepository::class),
+                $c->get(ICacheFactory::class)
             );
         });
 

lib/Service/CategoryRepository.php

@@ -5,7 +5,10 @@ namespace OCA\SideMenu\Service;
 use OC\App\AppStore\Fetcher\CategoryFetcher;
 use OCA\SideMenu\AppInfo\Application;
 use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\Exceptions\AppConfigTypeConflictException;
 use OCP\IAppConfig;
+use OCP\ICache;
+use OCP\ICacheFactory;
 use OCP\IConfig;
 use OCP\IUserSession;
 use OCP\L10N\IFactory;
@@ -33,6 +36,7 @@ class CategoryRepository
         protected IAppConfig $appConfig,
         protected ITimeFactory $timeFactory,
         protected LangRepository $langRepository,
+        protected ICacheFactory $cacheFactory,
     ) {
     }
 
@@ -94,6 +98,7 @@ class CategoryRepository
 
     public function clearCache(): void
     {
+        $this->getDistributedCache()?->remove(self::CACHE_KEY);
         $this->appConfig->deleteKey(Application::APP_ID, self::CACHE_KEY);
     }
 
@@ -117,18 +122,57 @@ class CategoryRepository
     }
 
     /**
-     * Returns the app store categories with only their names, from a
-     * cache that is stored lazily: it holds the names in every language,
-     * so it must not be loaded on every request with the other settings.
+     * Returns the app store categories with only their names. They are
+     * cached in the distributed cache (e.g. Redis) when one is configured,
+     * otherwise in a lazy app config value, so they are not loaded on
+     * every request with the other settings.
      */
     protected function getCategories(): array
     {
-        $cache = $this->appConfig->getValueArray(Application::APP_ID, self::CACHE_KEY, [], lazy: true);
+        $cache = $this->getDistributedCache();
 
-        if (isset($cache['expires'], $cache['categories']) && $cache['expires'] > $this->timeFactory->getTime()) {
-            return $cache['categories'];
+        if ($cache !== null) {
+            $categories = $cache->get(self::CACHE_KEY);
+
+            if (is_array($categories)) {
+                return $categories;
+            }
+        } else {
+            try {
+                $stored = $this->appConfig->getValueArray(Application::APP_ID, self::CACHE_KEY, [], lazy: true);
+            } catch (AppConfigTypeConflictException) {
+                // Stored with another type, e.g. set by hand; refreshed below
+                $stored = [];
+            }
+
+            if (isset($stored['expires'], $stored['categories']) && $stored['expires'] > $this->timeFactory->getTime()) {
+                return $stored['categories'];
+            }
         }
 
+        $categories = $this->fetchCategories();
+
+        // Don't cache an empty list, e.g. when the app store is unreachable
+        if (empty($categories)) {
+            return $categories;
+        }
+
+        $this->clearCache();
+
+        if ($cache !== null) {
+            $cache->set(self::CACHE_KEY, $categories, self::CACHE_TTL);
+        } else {
+            $this->appConfig->setValueArray(Application::APP_ID, self::CACHE_KEY, [
+                'expires' => $this->timeFactory->getTime() + self::CACHE_TTL,
+                'categories' => $categories,
+            ], lazy: true);
+        }
+
+        return $categories;
+    }
+
+    protected function fetchCategories(): array
+    {
         $langs = $this->getCachedLangs();
         $categories = [];
 
@@ -147,15 +191,13 @@ class CategoryRepository
             ];
         }
 
-        // Don't cache an empty list, e.g. when the app store is unreachable
-        if (!empty($categories)) {
-            $this->clearCache();
-            $this->appConfig->setValueArray(Application::APP_ID, self::CACHE_KEY, [
-                'expires' => $this->timeFactory->getTime() + self::CACHE_TTL,
-                'categories' => $categories,
-            ], lazy: true);
-        }
-
         return $categories;
     }
+
+    protected function getDistributedCache(): ?ICache
+    {
+        return $this->cacheFactory->isAvailable()
+            ? $this->cacheFactory->createDistributed(Application::APP_ID)
+            : null;
+    }
 }