Add ConfigureJsonOptions and rename CrdtConfig to Harmony

src/SIL.Harmony.Sample/SampleDbContext.cs

@@ -1,11 +1,12 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;
 using SIL.Harmony.Changes;
+using SIL.Harmony.Config;
 using SIL.Harmony.Db;
 
 namespace SIL.Harmony.Sample;
 
-public class SampleDbContext(DbContextOptions<SampleDbContext> options, IOptions<CrdtConfig> crdtConfig) : DbContext(options), ICrdtDbContext
+public class SampleDbContext(DbContextOptions<SampleDbContext> options, IOptions<HarmonyConfig> crdtConfig) : DbContext(options), ICrdtDbContext
 {
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {

src/SIL.Harmony.Tests/Adapter/CustomObjectAdapterTests.cs

@@ -4,14 +4,15 @@
 using Microsoft.Extensions.Options;
 using SIL.Harmony.Adapters;
 using SIL.Harmony.Changes;
+using SIL.Harmony.Config;
 using SIL.Harmony.Db;
 using SIL.Harmony.Entities;
 
 namespace SIL.Harmony.Tests.Adapter;
 
 public class CustomObjectAdapterTests
 {
-    public class MyDbContext(DbContextOptions<MyDbContext> options, IOptions<CrdtConfig> crdtConfig)
+    public class MyDbContext(DbContextOptions<MyDbContext> options, IOptions<HarmonyConfig> crdtConfig)
         : DbContext(options), ICrdtDbContext
     {
         public DbSet<MyClass> MyClasses { get; set; } = null!;

src/SIL.Harmony.Tests/ConfigTests.cs

@@ -1,3 +1,6 @@
+using System.Text.Json;
+using SIL.Harmony.Changes;
+using SIL.Harmony.Config;
 using SIL.Harmony.Sample.Changes;
 using SIL.Harmony.Sample.Models;
 using SIL.Harmony.Tests.Adapter;
@@ -9,7 +12,7 @@ public class ConfigTests
     [Fact]
     public void CanGetEntityTypes()
     {
-        var config = new CrdtConfig();
+        var config = new HarmonyConfig();
         config.ObjectTypeListBuilder.DefaultAdapter()
             .Add<Word>()
             .Add<Definition>();
@@ -23,10 +26,47 @@ public void CanGetEntityTypes()
     [Fact]
     public void CanGetChangeTypes()
     {
-        var config = new CrdtConfig();
+        var config = new HarmonyConfig();
         config.ChangeTypeListBuilder.Add<NewDefinitionChange>();
         config.ChangeTypeListBuilder.Add<SetWordTextChange>();
+        config.ChangeTypeListBuilder.Add<DeleteChange<Word>>();
         var types = config.ChangeTypes.ToArray();
-        types.Should().BeEquivalentTo([typeof(NewDefinitionChange), typeof(SetWordTextChange)]);
+        types.Should().BeEquivalentTo([
+            new RegisteredChangeType(typeof(NewDefinitionChange), nameof(NewDefinitionChange)),
+            new RegisteredChangeType(typeof(SetWordTextChange), nameof(SetWordTextChange)),
+            new RegisteredChangeType(typeof(DeleteChange<Word>), "delete:Word"),
+        ]);
+    }
+
+    [Fact]
+    public void ConfigureJsonOptions_applies_callback()
+    {
+        var config = new HarmonyConfig();
+        config.ConfigureJsonOptions(o => o.PropertyNamingPolicy = JsonNamingPolicy.CamelCase);
+
+        config.JsonSerializerOptions.PropertyNamingPolicy.Should().Be(JsonNamingPolicy.CamelCase);
+    }
+
+    [Fact]
+    public void ConfigureJsonOptions_composes_multiple_callbacks()
+    {
+        var config = new HarmonyConfig();
+        config.ConfigureJsonOptions(o => o.PropertyNamingPolicy = JsonNamingPolicy.CamelCase);
+        config.ConfigureJsonOptions(o => o.WriteIndented = true);
+
+        config.JsonSerializerOptions.PropertyNamingPolicy.Should().Be(JsonNamingPolicy.CamelCase);
+        config.JsonSerializerOptions.WriteIndented.Should().BeTrue();
+    }
+
+    [Fact]
+    public void ConfigureJsonOptions_throws_after_freeze()
+    {
+        var config = new HarmonyConfig();
+        _ = config.JsonSerializerOptions;
+
+        var act = () => config.ConfigureJsonOptions(o => o.WriteIndented = true);
+
+        act.Should().Throw<InvalidOperationException>()
+            .WithMessage("*JsonOptionsBuilder* frozen*");
     }
 }

src/SIL.Harmony.Tests/DataModelTestBase.cs

@@ -3,6 +3,7 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using SIL.Harmony.Changes;
+using SIL.Harmony.Config;
 using SIL.Harmony.Db;
 using SIL.Harmony.Sample;
 using SIL.Harmony.Sample.Changes;
@@ -38,7 +39,7 @@ public DataModelTestBase(SqliteConnection connection, bool alwaysValidate = true
             {
                 builder.UseSqlite(connection, true);
             }, performanceTest)
-            .Configure<CrdtConfig>(config => config.AlwaysValidateCommits = alwaysValidate)
+            .Configure<HarmonyConfig>(config => config.AlwaysValidateCommits = alwaysValidate)
             .Replace(ServiceDescriptor.Singleton<IHybridDateTimeProvider>(MockTimeProvider));
         configure?.Invoke(serviceCollection);
         _services = serviceCollection.BuildServiceProvider();

src/SIL.Harmony.Tests/PersistExtraDataTests.cs

@@ -1,5 +1,6 @@
 using Microsoft.Extensions.DependencyInjection;
 using SIL.Harmony.Changes;
+using SIL.Harmony.Config;
 using SIL.Harmony.Entities;
 
 namespace SIL.Harmony.Tests;
@@ -53,7 +54,7 @@ public PersistExtraDataTests()
     {
         _dataModelTestBase = new DataModelTestBase(configure: services =>
         {
-            services.Configure<CrdtConfig>(config =>
+            services.Configure<HarmonyConfig>(config =>
             {
                 config.ObjectTypeListBuilder.DefaultAdapter().Add<ExtraDataModel>();
                 config.ChangeTypeListBuilder.Add<CreateExtraDataModelChange>();

src/SIL.Harmony/Adapters/CustomAdapterProvider.cs

@@ -1,5 +1,6 @@
 using System.Text.Json.Serialization.Metadata;
 using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SIL.Harmony.Config;
 using SIL.Harmony.Entities;
 using SIL.Harmony.Helpers;
 

src/SIL.Harmony/Adapters/DefaultAdapterProvider.cs

@@ -1,5 +1,6 @@
 using System.Text.Json.Serialization.Metadata;
 using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SIL.Harmony.Config;
 using SIL.Harmony.Entities;
 using SIL.Harmony.Helpers;
 

src/SIL.Harmony/Changes/Change.cs

@@ -5,7 +5,7 @@ namespace SIL.Harmony.Changes;
 
 /// <summary>
 /// Polymorphic JSON for <see cref="IChange"/> is owned by
-/// <c>PeekThenConcreteChangeConverter</c> (via <see cref="CrdtConfig"/>), not
+/// <c>PeekThenConcreteChangeConverter</c> (via <see cref="Config.HarmonyConfig"/>), not
 /// <see cref="JsonPolymorphicAttribute"/>. Unknown <c>$type</c> values become
 /// <see cref="OpaqueChange"/>.
 /// </summary>

src/SIL.Harmony/Changes/ChangeContext.cs

@@ -1,13 +1,14 @@
+using SIL.Harmony.Config;
 using SIL.Harmony.Db;
 
 namespace SIL.Harmony.Changes;
 
 internal class ChangeContext : IChangeContext
 {
     private readonly SnapshotWorker _worker;
-    private readonly CrdtConfig _crdtConfig;
+    private readonly HarmonyConfig _crdtConfig;
 
-    internal ChangeContext(Commit commit, int commitIndex, IDictionary<Guid, ObjectSnapshot> intermediateSnapshots, SnapshotWorker worker, CrdtConfig crdtConfig)
+    internal ChangeContext(Commit commit, int commitIndex, IDictionary<Guid, ObjectSnapshot> intermediateSnapshots, SnapshotWorker worker, HarmonyConfig crdtConfig)
     {
         _worker = worker;
         _crdtConfig = crdtConfig;

src/SIL.Harmony/Changes/PeekThenConcreteChangeConverter.cs

@@ -7,7 +7,7 @@ namespace SIL.Harmony.Changes;
 
 /// <summary>
 /// Owns <see cref="IChange"/> discrimination. Requires <c>$type</c> as the first JSON property
-/// (matching synthetic write order from <see cref="CrdtConfig"/>).
+/// (matching synthetic write order from <see cref="Config.HarmonyConfig"/>).
 /// Known discriminators deserialize via cached concrete <see cref="JsonTypeInfo"/>;
 /// unknown → <see cref="OpaqueChange"/> preserving the raw payload.
 /// </summary>

src/SIL.Harmony/Config/ChangeTypeListBuilder.cs

@@ -0,0 +1,35 @@
+using SIL.Harmony.Changes;
+using SIL.Harmony.Entities;
+
+namespace SIL.Harmony.Config;
+
+public readonly record struct RegisteredChangeType(Type Type, string Discriminator);
+
+public class ChangeTypeListBuilder
+{
+    private bool _frozen;
+
+    /// <summary>
+    /// we call freeze when the builder is used to create a json serializer options, as it is not possible to add new types after that.
+    /// </summary>
+    internal void Freeze()
+    {
+        _frozen = true;
+    }
+
+    private void CheckFrozen()
+    {
+        if (_frozen) throw new InvalidOperationException($"{nameof(ChangeTypeListBuilder)} is frozen");
+    }
+
+    private readonly List<RegisteredChangeType> _types = [];
+    public IReadOnlyList<RegisteredChangeType> Types => _types.AsReadOnly();
+
+    public ChangeTypeListBuilder Add<TDerived>() where TDerived : IChange, IPolyType
+    {
+        CheckFrozen();
+        if (_types.Any(t => t.Type == typeof(TDerived))) return this;
+        _types.Add(new RegisteredChangeType(typeof(TDerived), TDerived.TypeName));
+        return this;
+    }
+}