Feat: define Redis governance serialization strategy (#33)

rian-be · rian-be · commit 603338a5e618 · 2026-06-26T00:57:00.000+02:00
diff --git a/Docs/Decision/Adr/ADR_031_Governance_Redis_Serialization_and_Document_Compatibility.md b/Docs/Decision/Adr/ADR_031_Governance_Redis_Serialization_and_Document_Compatibility.md
@@ -0,0 +1,78 @@
+# ADR-031: Governance Redis Serialization and Document Compatibility
+
+## Tag
+#adr_031
+
+## Status
+Accepted
+
+## Date
+2026-06-25
+
+## Scope
+ModularityKit.Mutator.Governance.Redis
+
+## Context
+
+The Redis provider persists governed mutation requests as serialized documents.
+
+That creates a compatibility boundary:
+
+- request data must round-trip without losing governance semantics
+- read models must tolerate heterogeneous metadata values
+- provider internals must avoid a Redis-specific domain model fork
+- future package versions should evolve the serialized shape deliberately, not accidentally
+
+The governance request model already contains nested structures such as:
+
+- mutation intent
+- request metadata
+- approval requirements
+- decision history
+- version resolution state
+
+Without an explicit serialization decision, the provider could drift into:
+
+- inconsistent JSON shapes across components
+- fragile metadata handling for object-valued entries
+- hidden coupling between runtime classes and Redis payload format
+
+## Decision
+
+The Redis provider serializes the existing governance request model directly as JSON documents and treats that JSON shape as the persisted document contract for the provider.
+
+The provider should:
+
+- serialize full `MutationRequest` documents rather than introduce a parallel storage DTO graph
+- keep provider serialization centralized in dedicated Redis serialization components
+- support heterogeneous metadata values through explicit converter handling
+- keep document materialization inside provider internals, not spread across query code paths
+- evolve document shape through deliberate package changes backed by ADRs when compatibility semantics change
+
+## Design Rationale
+
+- Reusing the governance model avoids translation layers that would duplicate request, approval, and decision semantics.
+- Centralized serialization keeps Redis persistence mechanics consistent across reads and writes.
+- Explicit converter support is necessary because governance metadata is intentionally flexible and may contain inferred object values.
+- A single persisted document contract makes provider behavior easier to reason about in tests, examples, and future migrations.
+
+## Consequences
+
+### Positive
+
+- Redis persistence stays aligned with governance runtime semantics.
+- Serialization behavior is easier to test because all provider paths use the same document contract.
+- Metadata and nested governance structures can round-trip without ad hoc per-query parsing.
+- Future compatibility changes now have an explicit decision boundary.
+
+### Negative
+
+- The provider is coupled to the serialized shape of the governance request model.
+- Backward-compatible evolution requires discipline when changing serialized request members.
+- JSON document size grows with request history and approval detail.
+
+## Related ADRs
+
+- ADR-022: Governance Request Decisions and Storage
+- ADR-029: Governance Redis Provider Package
+- ADR-030: Governance Redis Request Storage and Query Strategy
diff --git a/Docs/Decision/listadr.md b/Docs/Decision/listadr.md
@@ -44,5 +44,9 @@ These ADRs describe the `ModularityKit.Mutator.Governance` extension layer and i
 | ADR-026 | Governance Request Query API                         | [ADR-026](Adr/ADR_026_Governance_Request_Query_API.md)                         |
 | ADR-027 | Governed Execution Manager                           | [ADR-027](Adr/ADR_027_Governed_Execution_Manager.md)                           |
 | ADR-028 | Governance Approval Workflow Hardening               | [ADR-028](Adr/ADR_028_Governance_Approval_Workflow_Hardening.md)               |
+| ADR-029 | Governance Redis Provider Package                    | [ADR-029](Adr/ADR_029_Governance_Redis_Provider_Package.md)                    |
+| ADR-030 | Governance Redis Request Storage and Query Strategy  | [ADR-030](Adr/ADR_030_Governance_Redis_Request_Storage_and_Query_Strategy.md)  |
+| ADR-031 | Governance Redis Serialization and Document Compatibility | [ADR-031](Adr/ADR_031_Governance_Redis_Serialization_and_Document_Compatibility.md) |
+| ADR-032 | Governance Redis Concurrency and Index Maintenance Model | [ADR-032](Adr/ADR_032_Governance_Redis_Concurrency_and_Index_Maintenance_Model.md) |
 
 > See individual ADRs for detailed context, decision rationale, and consequences.
diff --git a/Tests/ModularityKit.Mutator.Governance.Redis.Tests/Serialization/Converters/RedisMutationRequestSerializerTests.cs b/Tests/ModularityKit.Mutator.Governance.Redis.Tests/Serialization/Converters/RedisMutationRequestSerializerTests.cs
@@ -0,0 +1,82 @@
+using ModularityKit.Mutator.Abstractions.Context;
+using ModularityKit.Mutator.Abstractions.Intent;
+using ModularityKit.Mutator.Abstractions.Policies;
+using ModularityKit.Mutator.Governance.Abstractions.Lifecycle.Model;
+using ModularityKit.Mutator.Governance.Abstractions.Requests.Factory;
+using ModularityKit.Mutator.Governance.Redis.Serialization;
+using Xunit;
+
+namespace ModularityKit.Mutator.Governance.Redis.Tests.Serialization;
+
+public sealed class RedisMutationRequestSerializerTests
+{
+    [Fact]
+    public void Roundtrip_preserves_request_shape_needed_by_governance_runtime()
+    {
+        var request = MutationRequestFactory.PendingApproval(
+            stateId: "tenant-42:roles",
+            stateType: "IamRoleState",
+            mutationType: "GrantRoleMutation",
+            intent: new MutationIntent
+            {
+                OperationName = "GrantRole",
+                Category = "Security",
+                Description = "Grant elevated access",
+                Tags = new HashSet<string> { "security", "urgent" },
+                EstimatedBlastRadius = BlastRadius.Module,
+                Metadata = new Dictionary<string, object>
+                {
+                    ["risk-owner"] = "platform"
+                }
+            },
+            context: MutationContext.User("requester-1", "Requester One", "Need emergency access") with
+            {
+                StateId = "tenant-42:roles",
+                Metadata = new Dictionary<string, object>
+                {
+                    ["source"] = "tests"
+                }
+            },
+            requirements:
+            [
+                new PolicyRequirement
+                {
+                    Type = "Approval",
+                    Description = "Requires security approval",
+                    Data = new Dictionary<string, object>
+                    {
+                        ["Approver"] = "security-lead",
+                        ["Reason"] = "Elevated role",
+                        ["StepOrder"] = 1L,
+                        ["RequiredApprovals"] = 1L
+                    }
+                }
+            ],
+            expectedStateVersion: "v10",
+            metadata: new Dictionary<string, object>
+            {
+                ["team"] = "security",
+                ["priority"] = "high"
+            })
+        with
+        {
+            CreatedAt = new DateTimeOffset(2026, 6, 25, 9, 0, 0, TimeSpan.Zero),
+            UpdatedAt = new DateTimeOffset(2026, 6, 25, 9, 5, 0, TimeSpan.Zero)
+        };
+
+        var json = RedisMutationRequestSerializer.Serialize(request);
+        var roundtrip = RedisMutationRequestSerializer.Deserialize(json);
+
+        Assert.Equal(request.RequestId, roundtrip.RequestId);
+        Assert.Equal(request.Status, roundtrip.Status);
+        Assert.Equal(request.PendingReason, roundtrip.PendingReason);
+        Assert.Equal(request.Intent.Category, roundtrip.Intent.Category);
+        Assert.Contains("security", roundtrip.Intent.Tags);
+        Assert.Equal(BlastRadiusScope.Module, roundtrip.Intent.EstimatedBlastRadius?.Scope);
+        Assert.Equal("security", roundtrip.Metadata["team"]);
+        Assert.Single(roundtrip.Requirements);
+        Assert.Single(roundtrip.ApprovalRequirements);
+        Assert.Equal("security-lead", roundtrip.ApprovalRequirements[0].ApproverId);
+        Assert.Equal(3, roundtrip.Decisions.Count);
+    }
+}
diff --git a/src/Redis/Serialization/Converters/InferredObjectJsonConverter.cs b/src/Redis/Serialization/Converters/InferredObjectJsonConverter.cs
@@ -0,0 +1,97 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace ModularityKit.Mutator.Governance.Redis.Serialization.Converters;
+
+/// <summary>
+/// Deserializes flexible metadata values into inferred CLR object graphs.
+/// </summary>
+internal sealed class InferredObjectJsonConverter : JsonConverter<object?>
+{
+    /// <summary>
+    /// Reads a JSON value into an inferred CLR object graph.
+    /// </summary>
+    /// <param name="reader">The JSON reader.</param>
+    /// <param name="typeToConvert">The target type.</param>
+    /// <param name="options">The serializer options.</param>
+    /// <returns>The inferred CLR value.</returns>
+    public override object? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        => ReadValue(ref reader);
+
+    /// <summary>
+    /// Writes an inferred CLR value back to JSON.
+    /// </summary>
+    /// <param name="writer">The JSON writer.</param>
+    /// <param name="value">The CLR value to write.</param>
+    /// <param name="options">The serializer options.</param>
+    public override void Write(Utf8JsonWriter writer, object? value, JsonSerializerOptions options)
+    {
+        if (value is null)
+        {
+            writer.WriteNullValue();
+            return;
+        }
+
+        JsonSerializer.Serialize(writer, value, value.GetType(), options);
+    }
+
+    private static object? ReadValue(ref Utf8JsonReader reader)
+    {
+        switch (reader.TokenType)
+        {
+            case JsonTokenType.True:
+                return true;
+            case JsonTokenType.False:
+                return false;
+            case JsonTokenType.Null:
+                return null;
+            case JsonTokenType.Number:
+                if (reader.TryGetInt64(out var longValue))
+                    return longValue;
+
+                if (reader.TryGetDecimal(out var decimalValue))
+                    return decimalValue;
+
+                return reader.GetDouble();
+            case JsonTokenType.String:
+                return reader.GetString();
+            case JsonTokenType.StartArray:
+            {
+                var list = new List<object?>();
+                while (reader.Read())
+                {
+                    if (reader.TokenType == JsonTokenType.EndArray)
+                        return list;
+
+                    list.Add(ReadValue(ref reader));
+                }
+
+                throw new JsonException("Unexpected end of JSON while reading array.");
+            }
+            case JsonTokenType.StartObject:
+            {
+                var dictionary = new Dictionary<string, object?>(StringComparer.Ordinal);
+
+                while (reader.Read())
+                {
+                    if (reader.TokenType == JsonTokenType.EndObject)
+                        return dictionary;
+
+                    if (reader.TokenType != JsonTokenType.PropertyName)
+                        throw new JsonException($"Unexpected token '{reader.TokenType}' while reading object.");
+
+                    var propertyName = reader.GetString() ?? string.Empty;
+
+                    if (!reader.Read())
+                        throw new JsonException("Unexpected end of JSON after property name.");
+
+                    dictionary[propertyName] = ReadValue(ref reader);
+                }
+
+                throw new JsonException("Unexpected end of JSON while reading object.");
+            }
+            default:
+                throw new JsonException($"Unsupported JSON token '{reader.TokenType}' for inferred object conversion.");
+        }
+    }
+}
diff --git a/src/Redis/Serialization/Converters/ReadOnlySetJsonConverterFactory.cs b/src/Redis/Serialization/Converters/ReadOnlySetJsonConverterFactory.cs
@@ -0,0 +1,61 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace ModularityKit.Mutator.Governance.Redis.Serialization.Converters;
+
+/// <summary>
+/// Creates converters for <see cref="IReadOnlySet{T}" /> payload members.
+/// </summary>
+internal sealed class ReadOnlySetJsonConverterFactory : JsonConverterFactory
+{
+    /// <summary>
+    /// Determines whether the supplied type is a supported read-only set type.
+    /// </summary>
+    /// <param name="typeToConvert">The type to inspect.</param>
+    /// <returns><see langword="true" /> when the type is supported; otherwise <see langword="false" />.</returns>
+    public override bool CanConvert(Type typeToConvert)
+        => typeToConvert.IsGenericType &&
+           typeToConvert.GetGenericTypeDefinition() == typeof(IReadOnlySet<>);
+
+    /// <summary>
+    /// Creates a converter instance for the supplied read-only set type.
+    /// </summary>
+    /// <param name="typeToConvert">The set type to convert.</param>
+    /// <param name="options">The serializer options.</param>
+    /// <returns>The created JSON converter.</returns>
+    public override JsonConverter CreateConverter(Type typeToConvert, JsonSerializerOptions options)
+    {
+        var itemType = typeToConvert.GetGenericArguments()[0];
+        var converterType = typeof(ReadOnlySetJsonConverter<>).MakeGenericType(itemType);
+        return (JsonConverter)Activator.CreateInstance(converterType)!;
+    }
+
+    /// <summary>
+    /// Converts a concrete read-only set payload for a specific item type.
+    /// </summary>
+    /// <typeparam name="T">The item type contained in the set.</typeparam>
+    private sealed class ReadOnlySetJsonConverter<T> : JsonConverter<IReadOnlySet<T>>
+    {
+        /// <summary>
+        /// Reads a JSON array into a read-only set.
+        /// </summary>
+        /// <param name="reader">The JSON reader.</param>
+        /// <param name="typeToConvert">The target type.</param>
+        /// <param name="options">The serializer options.</param>
+        /// <returns>The materialized read-only set.</returns>
+        public override IReadOnlySet<T> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+        {
+            var values = JsonSerializer.Deserialize<HashSet<T>>(ref reader, options);
+            return values ?? new HashSet<T>();
+        }
+
+        /// <summary>
+        /// Writes a read-only set as a JSON array.
+        /// </summary>
+        /// <param name="writer">The JSON writer.</param>
+        /// <param name="value">The set value to write.</param>
+        /// <param name="options">The serializer options.</param>
+        public override void Write(Utf8JsonWriter writer, IReadOnlySet<T> value, JsonSerializerOptions options)
+            => JsonSerializer.Serialize(writer, value.ToArray(), options);
+    }
+}
diff --git a/src/Redis/Serialization/RedisMutationRequestSerializer.cs b/src/Redis/Serialization/RedisMutationRequestSerializer.cs
@@ -0,0 +1,52 @@
+using System.Text.Json;
+using ModularityKit.Mutator.Governance.Abstractions.Requests.Model;
+using ModularityKit.Mutator.Governance.Redis.Serialization.Converters;
+
+namespace ModularityKit.Mutator.Governance.Redis.Serialization;
+
+/// <summary>
+/// Serializes governed mutation requests to and from Redis JSON payloads.
+/// </summary>
+internal static class RedisMutationRequestSerializer
+{
+    private static readonly JsonSerializerOptions SerializerOptions = CreateSerializerOptions();
+
+    /// <summary>
+    /// Serializes a governed mutation request into a Redis JSON payload.
+    /// </summary>
+    /// <param name="request">The request to serialize.</param>
+    /// <returns>The serialized JSON payload.</returns>
+    public static string Serialize(MutationRequest request)
+    {
+        ArgumentNullException.ThrowIfNull(request);
+        return JsonSerializer.Serialize(request, SerializerOptions);
+    }
+
+    /// <summary>
+    /// Deserializes a Redis JSON payload into a governed mutation request.
+    /// </summary>
+    /// <param name="json">The JSON payload to deserialize.</param>
+    /// <returns>The deserialized mutation request.</returns>
+    public static MutationRequest Deserialize(string json)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(json);
+
+        var request = JsonSerializer.Deserialize<MutationRequest>(json, SerializerOptions);
+        if (request is null)
+            throw new InvalidOperationException("Redis mutation request payload deserialized to null.");
+
+        return request;
+    }
+
+    private static JsonSerializerOptions CreateSerializerOptions()
+    {
+        var options = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
+        };
+
+        options.Converters.Add(new InferredObjectJsonConverter());
+        options.Converters.Add(new ReadOnlySetJsonConverterFactory());
+        return options;
+    }
+}
