自動生成などでsubParametersがnullのメニューアセットを指定した場合にエラるのを回避 (#263)

* 自動生成などでsubParametersがnullのメニューアセットを指定した場合にエラるのを回避

* chore: add test for null subparameter field issue

---------

Co-authored-by: bd_ <bd_@nadena.dev>

Assets/_ModularAvatar/EditModeTests/NullSubparameterTest.cs

@@ -0,0 +1,24 @@
+using nadena.dev.modular_avatar.core.editor;
+using NUnit.Framework;
+using UnityEngine;
+using VRC.SDK3.Avatars.Components;
+using VRC.SDK3.Avatars.ScriptableObjects;
+
+namespace modular_avatar_tests
+{
+    public class NullSubparameterTest : TestBase
+    {
+        [Test]
+        public void TestNullSubparametersField()
+        {
+            VRCExpressionsMenu menu = ScriptableObject.CreateInstance<VRCExpressionsMenu>();
+            var root = CreateRoot("root");
+
+            var avatar = root.GetComponent<VRCAvatarDescriptor>();
+            avatar.expressionsMenu = menu;
+
+            // This should not throw an exception
+            ParameterPolicy.ProbeParameters(root);
+        }
+    }
+}

Assets/_ModularAvatar/EditModeTests/NullSubparameterTest.cs.meta

@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: af0baf421bd9450d974871db9d25c2c4
+timeCreated: 1681041544

Packages/nadena.dev.modular-avatar/Editor/ParameterPolicy.cs

@@ -171,11 +171,14 @@ namespace nadena.dev.modular_avatar.core.editor
                     AddParam(control.parameter.name);
                 }
 
-                foreach (var subParam in control.subParameters)
+                if (control.subParameters != null)
                 {
-                    if (!string.IsNullOrWhiteSpace(subParam.name))
+                    foreach (var subParam in control.subParameters)
                     {
-                        AddParam(subParam.name);
+                        if (!string.IsNullOrWhiteSpace(subParam.name))
+                        {
+                            AddParam(subParam.name);
+                        }
                     }
                 }
 
@@ -314,4 +317,4 @@ namespace nadena.dev.modular_avatar.core.editor
             parameters = newParams;
         }
     }
-}
+}