Replace BinaryFormatter with DataContractSerializer

[MiroBrodlovaUnityGit]

Overview

This PR replaces all instances of BinaryFormatter with System.Runtime.Serialization.DataContractSerializer in this repo, and is part of Epic SCP-1555.

Previous Behavior

The package used deprecated BinaryFormatter which is deprecated in future .NET versions and may prevent assemblies from unloading or return incorrect results.

New & Expected Behavior

The package now uses DataContractSerializer for serialization/deserialization with [DataContract] and [DataMember] attributes added to all serialized classes.

Changes

• KdTree.cs: Replaced BinaryFormatter with DataContractSerializer in SaveToFile and LoadFromFile methods
• KdTreeNode.cs: Added [DataContract] and [DataMember] attributes to enable serialization
• Added [DataContract] and [DataMember] attributes to all serialized classes to ensure proper serialization

Further Context

• BinaryFormatter is deprecated in future .NET versions
• Epic SCP-1555 tracks this migration work
• DataContractSerializer was chosen as it does not require referencing additional assemblies

JIRA-ticket

• SCP-1555

Testing

Running the default job-suite. Please share if there are additional steps needed!

[unity-cla-assistant]

All committers have signed the CLA.

[codecov-github-com]

Codecov Report

All modified and coverable lines are covered by tests ✅

@@           Coverage Diff           @@
##           master     #641   +/-   ##
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  Coverage   35.57%   35.57%           
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  Files         277      277           
  Lines       34897    34897           
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  Hits        12416    12416           
  Misses      22481    22481           

Flag	Coverage Δ
mac_trunk	35.33% <ø> (-0.01%)	⬇️
win_trunk	35.23% <ø> (-0.01%)	⬇️

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[MiroBrodlovaUnityGit]

Marking this ready for review just for the purpose of triggering the automatic PR CI jobs (to get a gauge for how these changes fare)! Hope that's OK :)

[u-pr-agent]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis 🔶 SCP-1555 - Partially compliant Compliant requirements: Replace/avoid CoreCLR-incompatible (“forbidden”) APIs in packages (notably AppDomain-related and other analyzer-flagged APIs). Non-compliant requirements: Ensure no packages remain that have analyzer warnings/errors for forbidden API usage (Definition of Done). Requires further human verification: Verify changes via an appropriate test plan / CI as needed. Provide/attach a technical design document if required by the epic, or state why not needed. Ensure no packages remain that have analyzer warnings/errors for forbidden API usage (Definition of Done).

⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪ The diff is moderate-sized but changes serialization semantics and may require validation across multiple type combinations and runtime targets.

🏅 Score: 72 The migration removes `BinaryFormatter`, but the current `DataContractSerializer` usage on generic/internal types is likely to break without additional configuration and tests.

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Serialization Breakage DataContractSerializer for KdTree<TKey, TValue> may fail at runtime because generic parameters and member types (e.g., ITypeMath<TKey>, TKey[], TValue) are not guaranteed to be known/serializable; consider providing known types, a resolver, or redesigning persistence to serialize only the data needed (points/values) rather than runtime helpers like typeMath. [DataMember] private int dimensions; [DataMember] private ITypeMath<TKey> typeMath = null; [DataMember] private KdTreeNode<TKey, TValue> root = null; [DataMember] public AddDuplicateBehavior AddDuplicateBehavior { get; private set; } public bool Add(TKey[] point, TValue value) { var nodeToAdd = new KdTreeNode<TKey, TValue>(point, value); if (root == null) DataContract Visibility Data contract serialization typically requires members/types to be serializable and often expects public accessibility or explicit attributes; the internal child links and generic node type may need [DataMember] settings (e.g., IsRequired, EmitDefaultValue) and/or making the type/public members compatible, otherwise save/load may throw. [DataContract] class KdTreeNode<TKey, TValue> { public KdTreeNode() { } public KdTreeNode(TKey[] point, TValue value) { Point = point; Value = value; } [DataMember] public TKey[] Point; [DataMember] public TValue Value = default(TValue); [DataMember] public List<TValue> Duplicates = null; [DataMember] internal KdTreeNode<TKey, TValue> LeftChild = null; [DataMember] internal KdTreeNode<TKey, TValue> RightChild = null; Contract Consistency Adding [DataMember] to Count and AddDuplicateBehavior risks persisting derived/transient state; validate that Count matches the reconstructed tree and that AddDuplicateBehavior setter-only behavior is correctly restored on deserialize. [DataMember] public int Count { get; private set; }

Update review

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[u-pr-agent]

PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Impact
Possible issue	Prevent non-serializable strategy serialization Avoid serializing typeMath because it is typically an interface-backed strategy object and often not round-trippable with DataContractSerializer. Mark it as non-serialized and rehydrate it after load (e.g., via constructor/factory) to prevent runtime serialization failures. External/KdTree/KdTreeLib/KdTree.cs [47-48] -[DataMember] +[IgnoreDataMember] private ITypeMath<TKey> typeMath = null; Suggestion importance[1-10]: 8 __ Why: Serializing typeMath (an ITypeMath<TKey> interface strategy) is likely to fail with DataContractSerializer and also makes deserialized trees unusable without rehydrating the strategy; marking it with [IgnoreDataMember] is an important correctness fix.	Medium
More suggestions

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