Fix #352: Json Deserialization performance improvement

CLAUDE.md

@@ -29,7 +29,29 @@ dotnet-coverage collect "dotnet test SysML2.NET.sln --no-build" -f xml -o covera
 
 Test framework: **NUnit**. Test classes use `[TestFixture]` and `[Test]` attributes.
 
-**When writing or modifying unit tests** in any `*.Tests/` project: read `TESTING.md` at the repo root for the NUnit conventions (one `[Test]` per method-under-test, `Assert.That` everywhere, `Assert.EnterMultipleScope` only for consecutive asserts, mandatory positive + negative coverage, assertion idiom preferences, `Verify{MethodUnderTest}` naming).
+## Reading `TESTING.md` is MANDATORY
+
+**Before you write or modify a single line in any `*.Tests/` project, you MUST `Read` `TESTING.md` at the repo root — in full, in the current session.** It is the authoritative, binding specification for every NUnit fixture in this solution.
+
+This applies to *every* test change, including ones that feel too small to warrant it: adding one `[Test]`, adding an assertion to an existing one, or creating a new fixture alongside a production change. There is no "obvious enough to skip it" case.
+
+**Do NOT author tests from memory, from the conventions of another .NET project, or by copying the shape of a neighbouring fixture.** Several fixtures in the repo predate `TESTING.md` and violate it — imitating them reproduces the violation. `TESTING.md` wins over any existing file you are looking at.
+
+The rules most often got wrong, all of which have caused review churn:
+
+| Rule | Section | Get-it-wrong symptom |
+| --- | --- | --- |
+| One `[Test]` per method-under-test, all scenarios packed inside | §2, §10 | a family of `…_WhenX_DoesY` tests that share setup |
+| Name it `Verify{MethodUnderTest}` — no scenario suffix | §6, §10 | `Verify_that_foo_returns_bar`, `VerifyComputeFooWhenNull` |
+| One fixture per production type, mirroring its namespace | §1 | a second `…AspectTestFixture` bolted on beside the real one |
+| Every `[Test]` covers positive AND negative | §3, §10 | a happy-path-only test (very easy to do for an async overload) |
+| `Assert.That` only — never `Assert.Throws` / `IsTrue` / `AreEqual` | §4 | legacy NUnit API |
+| `Has.Count.EqualTo(n)`, not `result.Count, Is.EqualTo(n)` | §8 | asserting on `.Count` directly |
+| `Assert.EnterMultipleScope` only around **2+ consecutive** asserts | §5, §10 | a scope wrapping one long fluent chain |
+| Indexer / range over LINQ; `Is.SameAs` for POCO identity; `Is.EquivalentTo` when order is irrelevant | §8 | `.First()`, `.Last()`, `Is.EqualTo` on a POCO |
+| Assert an out-of-scope `NotSupportedException` stub — don't implement it | §9 | scope creep out of the test project |
+
+The table is a checklist, **not a substitute for reading the file** — it omits the reference fixtures (§11) and the criteria for when separated `[Test]` methods *are* allowed (§2).
 
 ## Architecture
 

SysML2.NET.CodeGenerator/Templates/Uml/Partials/core-json-dto-deserializer-uml-partial-template.hbs

@@ -1,117 +1,108 @@
-if (jsonElement.TryGetProperty("{{ property.Name }}"u8, out var {{ property.Name }}Property))
+if (reader.ValueTextEquals("{{ property.Name }}"u8))
 {
+{{ property.Name }}Seen = true;
+reader.Read();
+
 {{#if (Property.QueryIsReferenceProperty property)}}
     {{#if (Property.QueryIsEnumerable property)}}
-        foreach (var arrayItem in {{ property.Name }}Property.EnumerateArray())
-        {
-        if (arrayItem.TryGetProperty("@id"u8, out var {{ property.Name }}ExternalIdProperty))
-        {
-        var propertyValue = {{ property.Name }}ExternalIdProperty.GetString();
+        Utf8JsonReaderHelper.ExpectArrayStart(ref reader);
 
-        if (propertyValue != null)
+        while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
         {
-        dtoInstance.{{Property.WritePropertyName property}}.Add(Guid.Parse(propertyValue));
-        }
+        if (Utf8JsonReaderHelper.TryReadReferenceIdentifier(ref reader, out var {{ property.Name }}Value))
+        {
+        dtoInstance.{{Property.WritePropertyName property}}.Add({{ property.Name }}Value);
         }
         }
     {{ else }}
-        if ({{ property.Name }}Property.ValueKind == JsonValueKind.Null)
+        if (reader.TokenType == JsonTokenType.Null)
         {
         {{#if (Property.QueryIsNullable property) }}
             dtoInstance.{{Property.WritePropertyName property}} = null;
         {{else}}
             dtoInstance.{{Property.WritePropertyName property}} = Guid.Empty;
-            logger.LogDebug($"the {{ classContext.Name }}.{{Property.WritePropertyName property}} property was not found in the Json. The value is set to Guid.Empty");
+
+            if (logger.IsEnabled(LogLevel.Debug))
+            {
+            logger.LogDebug("the {{ classContext.Name }}.{{Property.WritePropertyName property}} property was not found in the Json. The value is set to Guid.Empty");
+            }
         {{/if}}
         }
-        else
-        {
-        if ({{ property.Name }}Property.TryGetProperty("@id"u8, out var {{ property.Name }}ExternalIdProperty))
-        {
-        var propertyValue = {{ property.Name }}ExternalIdProperty.GetString();
-
-        if (propertyValue != null)
+        else if (Utf8JsonReaderHelper.TryReadReferenceIdentifier(ref reader, out var {{ property.Name }}Value))
         {
-        dtoInstance.{{Property.WritePropertyName property}} = Guid.Parse(propertyValue);
-        }
-        }
+        dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Value;
         }
     {{/if}}
 {{ else }}
     {{#if (Property.QueryIsEnumerable property)}}
-        foreach (var arrayItem in {{ property.Name }}Property.EnumerateArray())
+        Utf8JsonReaderHelper.ExpectArrayStart(ref reader);
+
+        while (reader.Read() && reader.TokenType != JsonTokenType.EndArray)
         {
         {{#if (Property.QueryIsBool property )}}
-            var propertyValue = arrayItem.GetBoolean();
-
-            if (propertyValue != null)
-            {
-            dtoInstance.{{Property.WritePropertyName property}}.Add(propertyValue);
-            }
+            dtoInstance.{{Property.WritePropertyName property}}.Add(reader.GetBoolean());
         {{else if (Property.QueryIsEnum property )}}
             throw new NotImplementedException("Enumerable Enum - {{ classContext.Name }}.{{property.Name}} is not yet supported");
         {{else if (Property.QueryIsNumeric property )}}
             {{#if (Property.QueryIsInteger property) }}
-                dtoInstance.{{Property.WritePropertyName property}}.Add(arrayItem.GetInt32());
+                dtoInstance.{{Property.WritePropertyName property}}.Add(reader.GetInt32());
             {{else if (Property.QueryIsDouble property) }}
-                dtoInstance.{{Property.WritePropertyName property}}.Add(arrayItem.GetDouble());
+                dtoInstance.{{Property.WritePropertyName property}}.Add(reader.GetDouble());
             {{ else }}
                 throw new NotImplementedException("Enumerable Double - {{ classContext.Name }}.{{property.Name}} is not yet supported");
             {{/if}}
         {{else}}
-            var propertyValue = arrayItem.GetString();
+            var {{ property.Name }}Value = reader.GetString();
 
-            if (propertyValue != null)
+            if ({{ property.Name }}Value != null)
             {
-            dtoInstance.{{Property.WritePropertyName property}}.Add(propertyValue);
+            dtoInstance.{{Property.WritePropertyName property}}.Add({{ property.Name }}Value);
             }
         {{/if}}
         }
     {{ else if (Property.QueryIsNullable property) }}
         {{#if (Property.QueryIsBool property )}}
-            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetBoolean();
+            dtoInstance.{{Property.WritePropertyName property}} = reader.GetBoolean();
         {{else if (Property.QueryIsEnum property )}}
-            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Type.Name }}DeSerializer.DeserializeNullable({{ property.Name }}Property.GetString());
+            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Type.Name }}DeSerializer.DeserializeNullable(reader.GetString());
         {{else if (Property.QueryIsNumeric property )}}
             {{#if (Property.QueryIsInteger property) }}
-                dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetInt32();
+                dtoInstance.{{Property.WritePropertyName property}} = reader.GetInt32();
             {{else if (Property.QueryIsDouble property) }}
-                dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetDouble();
+                dtoInstance.{{Property.WritePropertyName property}} = reader.GetDouble();
             {{ else }}
                 new NotImplementedException("nullable - {{ classContext.Name }}.{{property.Name}} is not yet supported");
             {{/if}}
         {{else}}
-            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetString();
+            dtoInstance.{{Property.WritePropertyName property}} = reader.GetString();
         {{/if}}
     {{ else if (Property.QueryIsScalar property) }}
         {{#if (Property.QueryIsBool property )}}
-            if ({{ property.Name }}Property.ValueKind != JsonValueKind.Null)
+            if (reader.TokenType != JsonTokenType.Null)
             {
-            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetBoolean();
+            dtoInstance.{{Property.WritePropertyName property}} = reader.GetBoolean();
             }
         {{else if (Property.QueryIsEnum property )}}
-            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Type.Name }}DeSerializer.Deserialize({{ property.Name }}Property.GetString());
+            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Type.Name }}DeSerializer.Deserialize(reader.GetString());
         {{else if (Property.QueryIsNumeric property )}}
             {{#if (Property.QueryIsInteger property) }}
-                dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetInt32();
+                dtoInstance.{{Property.WritePropertyName property}} = reader.GetInt32();
             {{else if (Property.QueryIsDouble property) }}
-                dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Property.GetDouble();
+                dtoInstance.{{Property.WritePropertyName property}} = reader.GetDouble();
             {{ else }}
                 new NotImplementedException("Scalar - {{ classContext.Name }}.{{property.Name}} is not yet supported");
             {{/if}}
         {{else}}
-            var propertyValue = {{property.Name }}Property.GetString();
+            var {{ property.Name }}Value = reader.GetString();
 
-            if (propertyValue != null)
+            if ({{ property.Name }}Value != null)
             {
-            dtoInstance.{{Property.WritePropertyName property}} = propertyValue;
+            dtoInstance.{{Property.WritePropertyName property}} = {{ property.Name }}Value;
             }
         {{/if}}
     {{/if}}
 {{/if}}
-}
-else
-{
-logger.LogDebug("the {{ property.Name }} Json property was not found in the {{ classContext.Name }}: {Id}", dtoInstance.Id);
+
+continue;
 }
 

SysML2.NET.CodeGenerator/Templates/Uml/core-json-dto-deserialization-provider-uml-template.hbs

@@ -41,27 +41,27 @@ namespace SysML2.NET.Serializer.Json.Core.DTO
         /// <summary>
         /// a dictionary that provides delegates for deserialization
         /// </summary>
-        private static readonly Dictionary<string, Func<JsonElement, SerializationModeKind, bool, ILoggerFactory, IData>> DeSerializerActionMap = new Dictionary<string, Func<JsonElement, SerializationModeKind, bool, ILoggerFactory, IData>>
+        private static readonly Dictionary<string, DeSerializeDelegate> DeSerializerActionMap = new Dictionary<string, DeSerializeDelegate>
         {
             {{#each this as | class |}}
             { "{{ class.Name }}", {{ class.Name }}DeSerializer.DeSerialize },
             {{/each}}
         };
 
         /// <summary>
-        /// Provides the delegate <see cref="Func{JsonElement, SerializationModeKind, bool, ILoggerFactory, IData}"/> for the
+        /// Provides the <see cref="DeSerializeDelegate"/> for the
         /// <see cref="System.Type"/> that is to be deserialized
         /// </summary>
         /// <param name="typeName">
         /// The name of the subject <see cref="System.Type"/> that is to be serialized
         /// </param>
         /// <returns>
-        /// A Delegate of <see cref="Func{JsonElement, SerializationModeKind, bool, ILoggerFactory, IData}"/>
+        /// A <see cref="DeSerializeDelegate"/>
         /// </returns>
         /// <exception cref="NotSupportedException">
         /// Thrown when the <see cref="System.Type"/> is not supported.
         /// </exception>
-        internal static Func<JsonElement, SerializationModeKind, bool, ILoggerFactory, IData> Provide(string typeName)
+        internal static DeSerializeDelegate Provide(string typeName)
         {
             if (!DeSerializerActionMap.TryGetValue(typeName, out var func))
             {