From e1d580cb922e7a764d977732264e3a00671c116b Mon Sep 17 00:00:00 2001
From: Torben Dannhauer <torben@dannhauer.de>
Date: Thu, 25 Jun 2026 08:53:20 +0200
Subject: [PATCH] fix(nag): add missing Nag::isTaskViewFilter() helper

Task::process() calls Nag::isTaskViewFilter() when building the
complete-link return URL, but the method was never implemented.
Add a validator for Nag::VIEW_* filter values so smart-search
tab names are not mistaken for VIEW_INCOMPLETE.
---
 lib/Nag.php | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/lib/Nag.php b/lib/Nag.php
index b696f46..9e1c446 100644
--- a/lib/Nag.php
+++ b/lib/Nag.php
@@ -109,6 +109,24 @@ class Nag
      */
     public const VIEW_FUTURE_INCOMPLETE = 4;
 
+    /**
+     * Returns whether a value is a Nag::VIEW_* task list filter.
+     *
+     * @param mixed $filter  Tab name or show_completed value.
+     *
+     * @return bool
+     */
+    public static function isTaskViewFilter($filter): bool
+    {
+        if (!is_int($filter) && !(is_string($filter) && $filter !== '' && ctype_digit($filter))) {
+            return false;
+        }
+
+        $filter = (int) $filter;
+
+        return $filter >= self::VIEW_INCOMPLETE && $filter <= self::VIEW_FUTURE_INCOMPLETE;
+    }
+
     /**
      * WebDAV task list.
      */