Fix Action delegate's nullability#77
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XuuXiaolan merged 1 commit intoTeamXiaolan:mainfrom Feb 5, 2026
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In AchievementUIGetCanvas destructor removes a delegate from
DuskAchievementHandler.OnAchievementUnlocked, which triggers a warning
about possible null assignment.
protected override void OnDestroy()
{
DuskAchievementHandler.OnAchievementUnlocked -= QueuePopup;
}
Turns out, delgates implicitly implement `-=` operator in a way that "If
removal results in an empty list, the result is `null`."[1] So from static
typing POV, it doesn't matter that `OnAchievementUnlocked` action is
initialized with an empty `delegate { }` — it still sees the code as
nullable.
The fix is to consistently treat such action delegate as nullable.
That also means that a dummy `delegate { }` initialization is redundant.
[1]: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/subtraction-operator#delegate-removal
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In AchievementUIGetCanvas destructor removes a delegate from DuskAchievementHandler.OnAchievementUnlocked, which triggers a warning about possible null assignment.
Turns out, delgates implicitly implement
-=operator in a way that "If removal results in an empty list, the result isnull."1 So from static typing POV, it doesn't matter thatOnAchievementUnlockedaction is initialized with an emptydelegate { }— it still sees the code as nullable.The fix is to consistently treat such action delegate as nullable. That also means that a dummy
delegate { }initialization is redundant.