FIX: InputSystem warnings displayed with Unity editor 6000.6 version by josepmariapujol-unity · Pull Request #2381 · Unity-Technologies/InputSystem

josepmariapujol-unity · 2026-03-12T16:12:29Z

Description

InputSystem warnings displayed with Unity editor 6000.6 version.

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs(22,58): warning UAC1010: Field 'm_State' has [SerializeField] but its type 'UnityEngine.InputSystem.Editor.InputActionsEditorState' is not [Serializable]; Unity will ignore this field. Consider replacing [SerializeField] with [System.NonSerialized] or make the type [Serializable] if serialization is desired.

Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs(22,58): warning UAC1010: Field 'm_State' has [SerializeField] but its type 'UnityEngine.InputSystem.Editor.InputActionsEditorState' is not [Serializable]; Unity will ignore this field. Consider replacing [SerializeField] with [System.NonSerialized] or make the type [Serializable] if serialization is desired.

Packages/com.unity.inputsystem/InputSystem/Devices/Remote/InputRemoting.cs(383,37): warning UAC1001: Field 'layouts' is a candidate for serialization but Unity will skip it because its type 'UnityEngine.InputSystem.Utilities.InternedString' lacks [Serializable] attribute. To fix this, either: make the field private (if serialization is not desired), add [System.NonSerialized] (to explicitly mark it as non-serialized), or add [Serializable] to type 'UnityEngine.InputSystem.Utilities.InternedString' (if serialization is desired).

Packages/com.unity.inputsystem/InputSystem/Editor/Internal/InputStateWindow.cs(403,43): warning UAC1009: Field 'm_StateBuffers' uses 'byte[][]' which is not supported by Unity serialization (multidimensional arrays, jagged arrays, dictionaries, and other unsupported collections are not serialized); consider adding [System.NonSerialized] to suppress this warning

Packages/com.unity.inputsystem/InputSystem/InputManager.cs(4332,38): warning UAC1001: Field 'buffers' is a candidate for serialization but Unity will skip it because its type 'UnityEngine.InputSystem.LowLevel.InputStateBuffers' lacks [Serializable] attribute. To fix this, either: make the field private (if serialization is not desired), add [System.NonSerialized] (to explicitly mark it as non-serialized), or add [Serializable] to type 'UnityEngine.InputSystem.LowLevel.InputStateBuffers' (if serialization is desired).

Packages/com.unity.inputsystem/InputSystem/Events/InputEventTrace.cs(1567,46): warning UAC1010: Field 'm_StateFormat' has [SerializeField] but its type 'UnityEngine.InputSystem.Utilities.FourCC' is not [Serializable]; Unity will ignore this field. Consider replacing [SerializeField] with [System.NonSerialized] or make the type [Serializable] if serialization is desired.

Assets/Tests/InputSystem.Editor/InputActionReferenceEditorTests.cs(101,59): warning CS0618: 'Object.FindFirstObjectByType<T>()' is obsolete: 'FindFirstObjectByType has been deprecated because it relies on instance ID ordering. Use FindAnyObjectByType instead, which does not depend on ordering.'

Assets/QA/Tests/Xbox Controller Basic/Scripts/GamepadButtonState.cs(9,26): warning UAC1001: Field 'buttonToTrack' is a candidate for serialization but Unity will skip it because its type 'UnityEngine.InputSystem.Controls.ButtonControl' lacks [Serializable] attribute. To fix this, either: make the field private (if serialization is not desired), add [System.NonSerialized] (to explicitly mark it as non-serialized), or add [Serializable] to type 'UnityEngine.InputSystem.Controls.ButtonControl' (if serialization is desired).

Assets/Tests/InputSystem/Plugins/UITests.cs(4626,28): warning UAC1001: Field 'events' is a candidate for serialization but Unity will skip it because its type 'UITests.UICallbackReceiver.Event' lacks [Serializable] attribute. To fix this, either: make the field private (if serialization is not desired), add [System.NonSerialized] (to explicitly mark it as non-serialized), or add [Serializable] to type 'UITests.UICallbackReceiver.Event' (if serialization is desired).

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Testing status & QA

Please describe the testing already done by you and what testing you request/recommend QA to execute. If you used or created any testing project please link them here too for QA.

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Checklist

Before review:

Changelog entry added.
- Explains the change in Changed, Fixed, Added sections.
- For API change contains an example snippet and/or migration example.
- JIRA ticket linked, example (case %%). If it is a private issue, just add the case ID without a link.
- Jira port for the next release set as "Resolved".
Tests added/changed, if applicable.
- Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
- Performance tests.
- Integration tests.
Docs for new/changed API's.
- Xmldoc cross references are set correctly.
- Added explanation how the API works.
- Usage code examples added.
- The manual is updated, if needed.

During merge:

Commit message for squash-merge is prefixed with one of the list:
- NEW: ___.
- FIX: ___.
- DOCS: ___.
- CHANGE: ___.
- RELEASE: 1.1.0-preview.3.

josepmariapujol-unity · 2026-03-12T16:13:43Z

/crc

josepmariapujol-unity · 2026-03-12T16:17:17Z

/review

u-pr

The review identified critical serialization issues. Marking types with readonly fields or unmanaged pointers as [Serializable] will likely result in data loss or memory access violations. Additionally, there are concerns about serialization graph bloat for core controls.

_{🤖 Helpful? 👍/👎}

Packages/com.unity.inputsystem/InputSystem/Utilities/InternedString.cs

Packages/com.unity.inputsystem/InputSystem/State/InputStateBuffers.cs

Assets/Tests/InputSystem/Plugins/UITests.cs

Packages/com.unity.inputsystem/InputSystem/Controls/AxisControl.cs

u-pr

This review identified a few new points regarding the recent serialization changes:

Functional Issue (High): FourCC will lose its data during serialization because its private field is not marked with [SerializeField].
Verification Needed (Low): Ensure base classes of AxisControl are serializable to prevent data loss after deserialization.
Best Practice (Low): Marking m_StateBuffers in InputStateWindow as [NonSerialized] is a good practice as Unity does not support jagged array serialization.

Several other points (regarding InternedString, InputStateBuffers, and UITests) were excluded as they were already covered by existing comments.

_{🤖 Helpful? 👍/👎}

Packages/com.unity.inputsystem/InputSystem/Utilities/FourCC.cs

Packages/com.unity.inputsystem/InputSystem/Controls/AxisControl.cs

Packages/com.unity.inputsystem/InputSystem/Editor/Internal/InputStateWindow.cs

josepmariapujol-unity · 2026-03-12T16:44:14Z

/review

josepmariapujol-unity · 2026-03-12T16:45:05Z

/crc

u-pr

This review identified a critical architectural issue regarding the serialization of core input classes. While the PR aims to improve serializability for various components, marking the base InputControl class as [Serializable] introduces significant risks related to unmanaged memory and object initialization that could lead to runtime crashes.

_{🤖 Helpful? 👍/👎}

Packages/com.unity.inputsystem/InputSystem/Controls/InputControl.cs

u-pr · 2026-03-12T16:50:18Z

PR Reviewer Guide 🔍

(Review updated until commit `bed62b2`)

Here are some key observations to aid the review process:

⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪ The diff is small and mostly consists of attribute additions and a couple of editor/test adjustments, but it warrants a quick verification pass for behavioral side-effects.
🏅 Score: 90 The changes are straightforward and likely fix the reported warnings, with a few spots that should be validated for determinism and persistence behavior.
🧪 PR contains tests
🔒 No security concerns identified
⚡ Recommended focus areas for review Test Determinism `Object.FindAnyObjectByType<T>()` can return a non-deterministic instance when multiple objects of the same type exist; confirm the test scene/setup guarantees a single `InputActionBehaviour` instance (or consider a deterministic selection strategy if not). private static InputActionBehaviour GetBehaviour() => Object.FindAnyObjectByType<InputActionBehaviour>(); private static InputActionAsset GetAsset() => AssetDatabase.LoadAssetAtPath<InputActionAsset>(assetPath); State Persistence Changing `m_StateBuffers` from serialized to non-serialized means it won’t survive domain reloads/serialization cycles; ensure the window correctly rebuilds buffers on enable/selection changes and handles `null` safely. [NonSerialized] private byte[][] m_StateBuffers; [SerializeField] private int m_SelectedStateBuffer; [SerializeField] private bool m_CompareStateBuffers; [SerializeField] private bool m_ShowDifferentOnly; Serialization Impact Adding `[Serializable]` to foundational types (e.g., `InputControl` and `InputControl<TValue>`) can affect Unity/editor serialization and reflection behavior; validate this doesn’t cause unintended serialization attempts, inspector exposure, or compatibility issues in user projects. [Serializable] [DebuggerDisplay("{DebuggerDisplay(),nq}")] public abstract class InputControl {
Update review

🤖 Helpful? Please react with 👍/👎 | Questions❓Please reach out in Slack #ask-u-pr

u-pr · 2026-03-12T16:53:23Z

Persistent review updated to latest commit bed62b2

codecov-github-com · 2026-03-12T16:57:35Z

Codecov Report

All modified and coverable lines are covered by tests ✅

@@             Coverage Diff             @@
##           develop    #2381      +/-   ##
===========================================
- Coverage    77.90%   77.89%   -0.02%     
===========================================
  Files          476      481       +5     
  Lines        97613    97691      +78     
===========================================
+ Hits         76048    76098      +50     
- Misses       21565    21593      +28

Flag	Coverage Δ
inputsystem_MacOS_2022.3	`5.50% <ø> (-0.03%)`	⬇️
inputsystem_MacOS_2022.3_project	`75.41% <100.00%> (+0.01%)`	⬆️
inputsystem_MacOS_6000.0	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_MacOS_6000.0_project	`77.31% <100.00%> (+0.01%)`	⬆️
inputsystem_MacOS_6000.3	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_MacOS_6000.3_project	`77.31% <100.00%> (+0.01%)`	⬆️
inputsystem_MacOS_6000.4	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_MacOS_6000.4_project	`77.32% <100.00%> (+0.01%)`	⬆️
inputsystem_MacOS_6000.5	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_MacOS_6000.5_project	`77.31% <100.00%> (+0.01%)`	⬆️
inputsystem_MacOS_6000.6	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_MacOS_6000.6_project	`77.31% <100.00%> (+0.01%)`	⬆️
inputsystem_Ubuntu_2022.3_project	`75.20% <100.00%> (+0.01%)`	⬆️
inputsystem_Ubuntu_6000.0	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Ubuntu_6000.0_project	`77.11% <100.00%> (+0.01%)`	⬆️
inputsystem_Ubuntu_6000.3	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Ubuntu_6000.3_project	`77.11% <100.00%> (+0.01%)`	⬆️
inputsystem_Ubuntu_6000.4	`5.29% <ø> (-0.03%)`	⬇️
inputsystem_Ubuntu_6000.4_project	`77.12% <100.00%> (+0.01%)`	⬆️
inputsystem_Ubuntu_6000.5	`5.29% <ø> (-0.03%)`	⬇️
inputsystem_Ubuntu_6000.5_project	`77.12% <100.00%> (+<0.01%)`	⬆️
inputsystem_Ubuntu_6000.6	`5.29% <ø> (-0.03%)`	⬇️
inputsystem_Ubuntu_6000.6_project	`77.12% <100.00%> (+0.01%)`	⬆️
inputsystem_Windows_2022.3	`5.50% <ø> (-0.03%)`	⬇️
inputsystem_Windows_2022.3_project	`75.53% <100.00%> (+<0.01%)`	⬆️
inputsystem_Windows_6000.0	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Windows_6000.0_project	`77.43% <100.00%> (+0.01%)`	⬆️
inputsystem_Windows_6000.3	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Windows_6000.3_project	`77.43% <100.00%> (+0.01%)`	⬆️
inputsystem_Windows_6000.4	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Windows_6000.4_project	`77.44% <100.00%> (+0.01%)`	⬆️
inputsystem_Windows_6000.5	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Windows_6000.5_project	`77.44% <100.00%> (+0.01%)`	⬆️
inputsystem_Windows_6000.6	`5.28% <ø> (-0.03%)`	⬇️
inputsystem_Windows_6000.6_project	`77.44% <100.00%> (+0.01%)`	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...utSystem.Editor/InputActionReferenceEditorTests.cs	`97.61% <100.00%> (ø)`
Assets/Tests/InputSystem/Plugins/UITests.cs	`94.67% <ø> (ø)`
...ty.inputsystem/InputSystem/Controls/AxisControl.cs	`93.97% <ø> (ø)`
....inputsystem/InputSystem/Controls/ButtonControl.cs	`88.23% <ø> (ø)`
...y.inputsystem/InputSystem/Controls/InputControl.cs	`83.40% <ø> (ø)`
...em/InputSystem/Editor/Internal/InputStateWindow.cs	`0.00% <ø> (ø)`
.../Editor/UITKAssetEditor/InputActionsEditorState.cs	`53.36% <ø> (ø)`
...inputsystem/InputSystem/State/InputStateBuffers.cs	`96.11% <ø> (ø)`
....unity.inputsystem/InputSystem/Utilities/FourCC.cs	`68.62% <ø> (ø)`

... and 7 files with indirect coverage changes

josepmariapujol-unity · 2026-03-12T17:07:51Z

@jfreire-unity

Pauliusd01 · 2026-03-13T07:17:04Z

There seems to be one more warning left over:

Packages\com.unity.inputsystem\InputSystem\Devices\Remote\InputRemoting.cs(383,37): warning UAC1001: Field 'layouts' is a candidate for serialization but Unity will skip it because its type 'UnityEngine.InputSystem.Utilities.InternedString' lacks [Serializable] attribute. To fix this, either: make the field private (if serialization is not desired), add [System.NonSerialized] (to explicitly mark it as non-serialized), or add [Serializable] to type 'UnityEngine.InputSystem.Utilities.InternedString' (if serialization is desired).

josepmariapujol-unity · 2026-03-13T10:23:37Z

There seems to be one more warning left over:

Packages\com.unity.inputsystem\InputSystem\Devices\Remote\InputRemoting.cs(383,37): warning UAC1001: Field 'layouts' is a candidate for serialization but Unity will skip it because its type 'UnityEngine.InputSystem.Utilities.InternedString' lacks [Serializable] attribute. To fix this, either: make the field private (if serialization is not desired), add [System.NonSerialized] (to explicitly mark it as non-serialized), or add [Serializable] to type 'UnityEngine.InputSystem.Utilities.InternedString' (if serialization is desired).

Yes! I am not sure how to fix that. AI reviews are confusing me a lot.

ekcoh

Thanks for addressing these @josepmariapujol-unity!

josepmariapujol-unity added 4 commits March 12, 2026 16:15

fix

ac0ac4d

fix

34dd12e

Update InputActionsEditorState.cs

92f13b4

Update AxisControl.cs

cc62946

josepmariapujol-unity marked this pull request as ready for review March 12, 2026 16:12

josepmariapujol-unity self-assigned this Mar 12, 2026

josepmariapujol-unity requested review from Pauliusd01 and jfreire-unity March 12, 2026 16:15

u-pr bot reviewed Mar 12, 2026

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Packages/com.unity.inputsystem/InputSystem/Utilities/FourCC.cs Show resolved Hide resolved

Packages/com.unity.inputsystem/InputSystem/Controls/AxisControl.cs Show resolved Hide resolved

Packages/com.unity.inputsystem/InputSystem/Editor/Internal/InputStateWindow.cs Show resolved Hide resolved

josepmariapujol-unity and others added 3 commits March 12, 2026 17:29

Formatting

37ca867

Update InputControl.cs

c4c88d0

Remove Serializable attribute from InternedString

bed62b2

u-pr bot reviewed Mar 12, 2026

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Packages/com.unity.inputsystem/InputSystem/Controls/InputControl.cs Show resolved Hide resolved

josepmariapujol-unity requested a review from jfreire-unity March 12, 2026 17:14

josepmariapujol-unity requested a review from ekcoh March 13, 2026 10:23

ekcoh approved these changes Mar 13, 2026

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Pauliusd01 approved these changes Mar 13, 2026

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josepmariapujol-unity merged commit e1a0db7 into develop Mar 13, 2026
129 checks passed

josepmariapujol-unity deleted the input/warnings-6000.6a branch March 13, 2026 12:06

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