unity runtime_error ai_generated true

NullReferenceException: Physics.OverlapSphereNonAlloc returned null results array

ID: unity/physics-overlap-sphere-null

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95%Fix Rate
88%Confidence
1Evidence
2023-09-18First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
2020.3.48f1 active — — —
2021.3.30f1 active — — —
2022.3.10f1 active — — —

Root Cause

The results array passed to OverlapSphereNonAlloc is null or not initialized before calling the method.

generic

中文

传递给 OverlapSphereNonAlloc 的结果数组在调用方法之前为 null 或未初始化。

Official Documentation

https://docs.unity3d.com/ScriptReference/Physics.OverlapSphereNonAlloc.html

Workarounds

  1. 98% success Initialize the results array before the call: `Collider[] results = new Collider[10]; int count = Physics.OverlapSphereNonAlloc(center, radius, results);` 
    Initialize the results array before the call: `Collider[] results = new Collider[10]; int count = Physics.OverlapSphereNonAlloc(center, radius, results);`
  2. 95% success Check if results is null before passing: `if (results == null) results = new Collider[10]; int count = Physics.OverlapSphereNonAlloc(center, radius, results);` 
    Check if results is null before passing: `if (results == null) results = new Collider[10]; int count = Physics.OverlapSphereNonAlloc(center, radius, results);`

中文步骤

  1. Initialize the results array before the call: `Collider[] results = new Collider[10]; int count = Physics.OverlapSphereNonAlloc(center, radius, results);`
  2. Check if results is null before passing: `if (results == null) results = new Collider[10]; int count = Physics.OverlapSphereNonAlloc(center, radius, results);`

Dead Ends

Common approaches that don't work:

  1. 95% fail

    The null check doesn't prevent the NullReferenceException from being thrown when accessing the uninitialized array in the method call itself.

  2. 99% fail

    The error is about the array being null, not its size; size is irrelevant if the array reference is null.

  3. 30% fail

    OverlapSphere allocates a new array each call, which may fix the immediate null issue but introduces GC pressure and doesn't solve the root cause of uninitialized array.