fix double free in kitty desktop notification parsing

src/terminal/kitty/desktop.zig

@@ -19,7 +19,7 @@ payload: ?[]const u8 = null,
 terminator: Terminator = .st,
 
 /// we use an arena to make cleaning up allocations simpler
-arena: std.heap.ArenaAllocator,
+arena: ?std.heap.ArenaAllocator = null,
 
 /// these are used internally by the parser to keep track of
 /// locations in the buffer, they should be ignored outside of
@@ -259,7 +259,8 @@ pub fn init(gpa_alloc: std.mem.Allocator, option_start: usize) KittyDesktopNotif
 }
 
 pub fn deinit(self: *KittyDesktopNotification) void {
-    self.arena.deinit();
+    if (self.arena) |arena| arena.deinit();
+    self.arena = null;
 }
 
 pub fn startOption(self: *KittyDesktopNotification, option_start: usize) void {
@@ -324,7 +325,11 @@ pub fn endOption(self: *KittyDesktopNotification, parser: *Parser, option_end: u
     self._internal.key_end = null;
     self._internal.value_start = null;
 
-    const alloc = self.arena.allocator();
+    const alloc = (self.arena orelse {
+        log.warn("no arena?", .{});
+        parser.state = .invalid;
+        return;
+    }).allocator();
 
     switch (key) {
         // action
@@ -539,7 +544,11 @@ pub fn end(self: *KittyDesktopNotification, parser: *Parser, option_end: usize)
         return;
     }
 
-    const alloc = self.arena.allocator();
+    const alloc = (self.arena orelse {
+        log.warn("no arena?", .{});
+        parser.state = .invalid;
+        return;
+    }).allocator();
 
     if (self.metadata.e) {
         const size = simd.base64.maxLen(value);