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Unity Engine

AutoStaticsCleanupAttribute

Resets static variables automatically on entering or exiting Play mode with domain reload disabled.
Read time 5 minutesLast updated 6 days ago

Definition

[AttributeUsage(AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Property|AttributeTargets.Field|AttributeTargets.Event, AllowMultiple = true)]public sealed class AutoStaticsCleanupAttribute : Attribute

Remarks

This attribute can be applied to classes, structs, fields, properties, and events. Applying it to a class or struct ensures all static members of the class or struct are automatically reset. Any class or struct that has this attribute, or that has a member with this attribute, must be declared 
partial
, along with all its containing types, to allow the source generator to inject clean-up code. Otherwise the analyzer reports 
UAL0012
and the source generator generates no clean-up code for that type. If the analyzer is disabled, the compiler reports 
CS0260
instead.
[AutoStaticsCleanup]
resets state as follows:
  • Static fields are restored by reapplying their field initializer. If no initializer is present, the field is reset to its C# default value. For example, 
    static int myInt = 5;
    resets to 
    5
    .
  • For reference-type fields initialized with 
    new
    , the initializer is evaluated again, so a new instance is created. For example, 
    static MyObj obj = null;
    resets to 
    null
    and 
    static MyObj obj = new();
    creates a fresh 
    MyObj
    when Play mode starts.
  • readonly
    static collection fields (such as 
    List<T>
    , 
    Dictionary<TKey,TValue>
    , 
    HashSet<T>
    , and any type with a parameterless 
    Clear
    method) are a special case: instead of replacing the instance, the existing collection is preserved and 
    Clear
    is called. Non-readonly static collections are reset normally by reapplying their initializer. For 
    readonly
    fields, the initializer must either be omitted, use 
    new()
    , or use the exact declared type — for example, 
    = new List<string>()
    .
  • Fields whose type has an accessible parameterless 
    Dispose
    method are disposed before they're reset. The generator calls 
    Dispose
    on the current value, then applies the reset described previously. Only non-
    readonly
    fields are disposed, because 
    readonly
    collection fields use 
    Clear
    instead. A 
    Dispose
    method counts as accessible when the class that declares the field can call it, so a 
    private
    Dispose
    on that same class is used, and so is a 
    protected
    Dispose
    inherited from a base class. A 
    private
    or 
    protected
    Dispose
    on an unrelated type is ignored, and the field is only reset. A struct field is disposed even when it still holds its default value, so write its 
    Dispose
    method to be safe to call on a default instance.
For more information, refer to Enter Play mode with domain reload disabled in the manual.

Examples

using Unity.Scripting.LifecycleManagement;using UnityEngine;public partial class MyCounterClass : MonoBehaviour{    [AutoStaticsCleanup]    public static int cleanedUpCounter = 0;    void Start()    {        Debug.Log(cleanedUpCounter); // Counter value is reset each time entering Play Mode        cleanedUpCounter++;    }}

Inheritance

Inherited Members