fix: make user search case-insensitive across all supported databases

MySQL/MariaDB already handles this via collation (LIKE), PostgreSQL now
uses ILIKE, and SQLite uses LOWER(username) LIKE since its LIKE is only
ASCII case-insensitive. Applies to both FulltextFilter (API/user directory
search) and UserRepository::getIdsForUsername (mention autocomplete etc).

Author: imorland

framework/core/src/User/Search/FulltextFilter.php

@@ -26,23 +26,38 @@ public function __construct(
     ) {
     }
 
+    public function search(SearchState $state, string $value): void
+    {
+        $state->getQuery()
+            ->whereIn(
+                'id',
+                match ($state->getQuery()->getConnection()->getDriverName()) {
+                    'pgsql' => $this->getUserSearchSubQuery($value, 'ilike'),
+                    'sqlite' => $this->getUserSearchSubQueryLower($value),
+                    default => $this->getUserSearchSubQuery($value, 'like'),
+                }
+            );
+    }
+
     /**
      * @return Builder<User>
      */
-    private function getUserSearchSubQuery(string $searchValue): Builder
+    private function getUserSearchSubQuery(string $searchValue, string $operator): Builder
     {
         return $this->users
             ->query()
             ->select('id')
-            ->where('username', 'like', "$searchValue%");
+            ->where('username', $operator, "$searchValue%");
     }
 
-    public function search(SearchState $state, string $value): void
+    /**
+     * @return Builder<User>
+     */
+    private function getUserSearchSubQueryLower(string $searchValue): Builder
     {
-        $state->getQuery()
-            ->whereIn(
-                'id',
-                $this->getUserSearchSubQuery($value)
-            );
+        return $this->users
+            ->query()
+            ->select('id')
+            ->whereRaw('LOWER(username) LIKE ?', [strtolower($searchValue).'%']);
     }
 }

framework/core/src/User/UserRepository.php

@@ -97,9 +97,22 @@ public function getIdsForUsername(string $string, ?User $actor = null): array
     {
         $string = $this->escapeLikeString($string);
 
-        $query = $this->query()->where('username', 'like', '%'.$string.'%')
-            ->orderByRaw('username = ? desc', [$string])
-            ->orderByRaw('username like ? desc', [$string.'%']);
+        $query = $this->query();
+
+        match ($query->getConnection()->getDriverName()) {
+            'pgsql' => $query
+                ->where('username', 'ilike', '%'.$string.'%')
+                ->orderByRaw('username = ? desc', [$string])
+                ->orderByRaw('username ilike ? desc', [$string.'%']),
+            'sqlite' => $query
+                ->whereRaw('LOWER(username) LIKE ?', ['%'.strtolower($string).'%'])
+                ->orderByRaw('LOWER(username) = ? desc', [strtolower($string)])
+                ->orderByRaw('LOWER(username) LIKE ? desc', [strtolower($string).'%']),
+            default => $query
+                ->where('username', 'like', '%'.$string.'%')
+                ->orderByRaw('username = ? desc', [$string])
+                ->orderByRaw('username like ? desc', [$string.'%']),
+        };
 
         return $this->scopeVisibleTo($query, $actor)->pluck('id')->all();
     }