From 9486b530dfda070dd6ec4d7739ed7c68a77f51d5 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Mon, 29 Dec 2025 15:13:48 +1100
Subject: [PATCH] Assert fp is not None

---
 src/PIL/JpegXlImagePlugin.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/PIL/JpegXlImagePlugin.py b/src/PIL/JpegXlImagePlugin.py
index c4c2adac9..f4dd6da1e 100644
--- a/src/PIL/JpegXlImagePlugin.py
+++ b/src/PIL/JpegXlImagePlugin.py
@@ -28,6 +28,7 @@ class JpegXlImageFile(ImageFile.ImageFile):
     __frame = 0
 
     def _open(self) -> None:
+        assert self.fp is not None
         self._decoder = _jpegxl.JpegXlDecoder(self.fp.read())
 
         (