MergePhysBoneで特定の操作をすると、ビルド時にエラーが発生する

[akanevrc]

私のプロジェクトのアバターに以下の操作を行なった結果、ビルド時にエラーが発生しましたのでご報告します。

• AvatarOptimizer v0.3.1
• アバターはPrefab Variant
• アバター以下のオブジェクトAにMergePhysBoneを追加し、PhysBoneを2つほどセットする
• アバター以下のオブジェクトB（Aとは別の親をもつ）にMergePhysBoneをCopy & Paste as Newする
• BのMergePhysBoneのPhysBoneを2つとも削除
• 改めてBにBの兄弟のPhysBoneをセット
• ビルドすると画像のエラーが出る

追記：エラーメッセージ

System.ArgumentException: Object at index 0 is null
  at (wrapper managed-to-native) UnityEditor.SerializedObject.InternalCreate(UnityEngine.Object[],UnityEngine.Object)
  at UnityEditor.SerializedObject..ctor (UnityEngine.Object obj) [0x00008] in <a259d3c004024353a2c217da97495055>:0 
  at Anatawa12.AvatarOptimizer.MergePhysBoneEditorModificationUtils..ctor (UnityEditor.SerializedObject serializedObject) [0x00014] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\MergePhysBoneEditor.cs:88 
  at Anatawa12.AvatarOptimizer.Processors.MergePhysBoneProcessor+MergePhysBoneMerger..ctor (UnityEditor.SerializedObject serializedObject) [0x00000] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\Processors\MergePhysBoneProcessor.cs:108 
  at Anatawa12.AvatarOptimizer.Processors.MergePhysBoneProcessor.DoMerge (Anatawa12.AvatarOptimizer.MergePhysBone merge, Anatawa12.AvatarOptimizer.OptimizerSession session) [0x001d1] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\Processors\MergePhysBoneProcessor.cs:74 
  at Anatawa12.AvatarOptimizer.Processors.MergePhysBoneProcessor.Process (Anatawa12.AvatarOptimizer.OptimizerSession session) [0x00018] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\Processors\MergePhysBoneProcessor.cs:18 
  at Anatawa12.AvatarOptimizer.OptimizerProcessor.DoProcessObject (Anatawa12.AvatarOptimizer.OptimizerSession session) [0x0000d] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\OptimizerProcessor.cs:108 
  at Anatawa12.AvatarOptimizer.OptimizerProcessor.ProcessObject (Anatawa12.AvatarOptimizer.OptimizerSession session) [0x0001e] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\OptimizerProcessor.cs:90 
  at Anatawa12.AvatarOptimizer.OptimizerProcessor.OnPreprocessAvatar (UnityEngine.GameObject avatarGameObject) [0x00002] in D:\MyDocuments\VRChatProjects\VRCAkaneAvatars\Packages\com.anatawa12.avatar-optimizer\Editor\OptimizerProcessor.cs:65 
UnityEngine.Debug:LogError (object)
Anatawa12.AvatarOptimizer.OptimizerProcessor:OnPreprocessAvatar (UnityEngine.GameObject) (at Packages/com.anatawa12.avatar-optimizer/Editor/OptimizerProcessor.cs:70)
VRC.SDKBase.Editor.BuildPipeline.VRCBuildPipelineCallbacks:OnPreprocessAvatar (UnityEngine.GameObject)
VRC.SDK3.Builder.VRCAvatarBuilder:ExportCurrentAvatarResource (UnityEngine.Object,bool)
VRC.SDK3.Builder.VRCAvatarBuilder:ExportAndUploadAvatarBlueprint (UnityEngine.GameObject)
VRC.SDKBase.Editor.VRC_SdkBuilder:ExportAndUploadAvatarBlueprint (UnityEngine.GameObject)
VRC.SDK3.Editor.VRCSdkControlPanelAvatarBuilder3A:OnGUIAvatar (VRC.SDKBase.VRC_AvatarDescriptor) (at Packages/com.vrchat.avatars/Editor/VRCSDK/SDK3A/VRCSdkControlPanelAvatarBuilder3A.cs:592)
VRC.SDKBase.Editor.VRCSdkControlPanelAvatarBuilder:ShowBuilder () (at Packages/com.vrchat.base/Editor/VRCSDK/Dependencies/VRChat/ControlPanel/VRCSdkControlPanelAvatarBuilder.cs:160)
VRCSdkControlPanel:ShowBuilders () (at Packages/com.vrchat.base/Editor/VRCSDK/Dependencies/VRChat/ControlPanel/VRCSdkControlPanelBuilder.cs:355)
VRCSdkControlPanel:OnGUI () (at Packages/com.vrchat.base/Editor/VRCSDK/Dependencies/VRChat/ControlPanel/VRCSdkControlPanel.cs:215)
UnityEngine.GUIUtility:ProcessEvent (int,intptr)

The VRCSDK build was aborted because the VRCSDKPreprocessAvatarCallback 'OptimizerProcessor' reported a failure.
UnityEngine.Debug:LogError (object)
VRC.SDKBase.Editor.BuildPipeline.VRCBuildPipelineCallbacks:OnPreprocessAvatar (UnityEngine.GameObject)
VRC.SDK3.Builder.VRCAvatarBuilder:ExportCurrentAvatarResource (UnityEngine.Object,bool)
VRC.SDK3.Builder.VRCAvatarBuilder:ExportAndUploadAvatarBlueprint (UnityEngine.GameObject)
VRC.SDKBase.Editor.VRC_SdkBuilder:ExportAndUploadAvatarBlueprint (UnityEngine.GameObject)
VRC.SDK3.Editor.VRCSdkControlPanelAvatarBuilder3A:OnGUIAvatar (VRC.SDKBase.VRC_AvatarDescriptor) (at Packages/com.vrchat.avatars/Editor/VRCSDK/SDK3A/VRCSdkControlPanelAvatarBuilder3A.cs:592)
VRC.SDKBase.Editor.VRCSdkControlPanelAvatarBuilder:ShowBuilder () (at Packages/com.vrchat.base/Editor/VRCSDK/Dependencies/VRChat/ControlPanel/VRCSdkControlPanelAvatarBuilder.cs:160)
VRCSdkControlPanel:ShowBuilders () (at Packages/com.vrchat.base/Editor/VRCSDK/Dependencies/VRChat/ControlPanel/VRCSdkControlPanelBuilder.cs:355)
VRCSdkControlPanel:OnGUI () (at Packages/com.vrchat.base/Editor/VRCSDK/Dependencies/VRChat/ControlPanel/VRCSdkControlPanel.cs:215)
UnityEngine.GUIUtility:ProcessEvent (int,intptr)

[anatawa12]

Copy Componentを想定していませんでした。修正します