From 41088ef0cb7baabc8dd19dc3de90f57d5608f2e7 Mon Sep 17 00:00:00 2001
From: FabianLars <github@fabianlars.de>
Date: Sun, 23 Feb 2025 17:43:55 +0100
Subject: [PATCH] fix(single-instance): Check if pointer is null

fixes #2405
---
 .changes/single-instance-nullpointer-deref.md        | 6 ++++++
 plugins/process/permissions/schemas/schema.json      | 2 +-
 plugins/single-instance/src/platform_impl/windows.rs | 5 +++++
 3 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 .changes/single-instance-nullpointer-deref.md

diff --git a/.changes/single-instance-nullpointer-deref.md b/.changes/single-instance-nullpointer-deref.md
new file mode 100644
index 00000000..13e212b2
--- /dev/null
+++ b/.changes/single-instance-nullpointer-deref.md
@@ -0,0 +1,6 @@
+---
+single-instance: patch
+single-instance-js: patch
+---
+
+Fixed an issue that caused `null pointer dereference occurred` errors on rust nightly.
diff --git a/plugins/process/permissions/schemas/schema.json b/plugins/process/permissions/schemas/schema.json
index 1243c7d3..95f67149 100644
--- a/plugins/process/permissions/schemas/schema.json
+++ b/plugins/process/permissions/schemas/schema.json
@@ -322,4 +322,4 @@
       ]
     }
   }
-}
+}
\ No newline at end of file
diff --git a/plugins/single-instance/src/platform_impl/windows.rs b/plugins/single-instance/src/platform_impl/windows.rs
index e99f405d..2f6992ee 100644
--- a/plugins/single-instance/src/platform_impl/windows.rs
+++ b/plugins/single-instance/src/platform_impl/windows.rs
@@ -118,6 +118,11 @@ unsafe extern "system" fn single_instance_window_proc<R: Runtime>(
 ) -> LRESULT {
     let data_ptr = GetWindowLongPtrW(hwnd, GWL_USERDATA)
         as *mut (AppHandle<R>, Box<SingleInstanceCallback<R>>);
+
+    if data_ptr.is_null() {
+        return DefWindowProcW(hwnd, msg, wparam, lparam);
+    }
+
     let (app_handle, callback) = &mut *data_ptr;
 
     match msg {