List every schema an allOf merges in API reference

src/Elastic.ApiExplorer/Components/PropertyTree/ApiProperty.cs

@@ -145,6 +145,9 @@ public record ApiProperty
 
 	public TypePageLink? TypeLink { get; init; }
 
+	/// <summary>Further schemas an <c>allOf</c> merges in; the row's type names only the first.</summary>
+	public IReadOnlyList<TypePageLink> AlsoIncludes { get; init; } = [];
+
 	public required bool IsCollapsible { get; init; }
 	public required bool DefaultExpanded { get; init; }
 	public required int NestedCount { get; init; }

src/Elastic.ApiExplorer/Components/PropertyTree/ApiPropertyMarkdown.cs

@@ -74,9 +74,22 @@ private static void WriteProperty(StringBuilder markdown, ApiProperty property,
 		if (property.TypeLink is { Url: { Length: > 0 } url })
 			WriteNestedLine(markdown, depth, $"See {ApiCommonMark.Link(property.TypeLink.TypeName, url)}");
 
+		WriteAlsoIncludes(markdown, property, depth);
+
 		WriteChildren(markdown, property, apiBaseUrl, depth);
 	}
 
+	private static void WriteAlsoIncludes(StringBuilder markdown, ApiProperty property, int depth)
+	{
+		if (property.AlsoIncludes.Count == 0)
+			return;
+
+		var names = property.AlsoIncludes.Select(
+			t => t.Url is { Length: > 0 } url ? ApiCommonMark.Link(t.TypeName, url) : $"`{t.TypeName}`"
+		);
+		WriteNestedLine(markdown, depth, "Also includes: " + string.Join(", ", names));
+	}
+
 	private static void WriteArrayItemType(StringBuilder markdown, ApiProperty property, int depth)
 	{
 		if (property.ArrayItemTypeName is { Length: > 0 })

src/Elastic.ApiExplorer/Components/PropertyTree/ApiPropertyTreeBuilder.cs

@@ -216,6 +216,7 @@ private ApiProperty BuildProperty(PropertyRow row, PropertyTreeScope scope)
 			// Type annotation already reads "[] …"; skip the redundant "Array of:" row.
 			ArrayItemTypeName = null,
 			TypeLink = typeLink,
+			AlsoIncludes = BuildAlsoIncludes(typeInfo),
 			IsCollapsible = expansion.IsCollapsible,
 			DefaultExpanded = expansion.DefaultExpanded,
 			NestedCount = expansion.NestedCount,
@@ -382,6 +383,12 @@ private static TypeAnnotation WithTypeLink(TypeAnnotation type, TypePageLink? ty
 		return new TypeAnnotation(spans);
 	}
 
+	private IReadOnlyList<TypePageLink> BuildAlsoIncludes(TypeInfo typeInfo) =>
+		typeInfo.AlsoIncludes?.Select(
+			c => new TypePageLink(c.Name, c.HasLink ? SchemaHelpers.GetContainerPageUrl(options.ApiRootUrl, c.Name) : null)
+		).ToArray()
+			?? [];
+
 	private TypePageLink? BuildTypeLink(TypeInfo typeInfo, Expansion expansion)
 	{
 		string? linkedTypeName = null;

src/Elastic.ApiExplorer/Components/PropertyTree/_Partials/_PropertyItem.cshtml

@@ -36,6 +36,28 @@
 			</a>
 		</dd>
 	}
+	@if (Model.AlsoIncludes.Count > 0)
+	{
+		<dd class="also-includes">
+			<span class="values-label">Also includes:</span>
+			@for (var i = 0; i < Model.AlsoIncludes.Count; i++)
+			{
+				var included = Model.AlsoIncludes[i];
+				if (i > 0)
+				{
+					<text>, </text>
+				}
+				if (included.Url is { Length: > 0 } includedUrl)
+				{
+					<code class="schema-type"><a href="@includedUrl" class="@SchemaHelpers.LinkedCssClass" data-hx-boost="false">@included.TypeName</a></code>
+				}
+				else
+				{
+					<code class="schema-type">@included.TypeName</code>
+				}
+			}
+		</dd>
+	}
 	@(await RenderPartialAsync<_EnumValues, EnumValueList>(new EnumValueList(Model.EnumValues)))
 	@if (Model.Union is not null)
 	{

src/Elastic.ApiExplorer/Model/SchemaAnalyzer.cs

@@ -514,7 +514,8 @@ private TypeInfo ClassifyType(IOpenApiSchema? schema)
 						named.IsValueType,
 						named.ValueTypeBase,
 						IsLinkedType(named.TypeName),
-						null
+						null,
+						AlsoIncludes: GetComposedTypes(refSchemas)
 					);
 				}
 			}
@@ -633,6 +634,28 @@ private bool TrySplitAllOfUnion(IList<IOpenApiSchema> allOf, out AllOfUnion spli
 		return false;
 	}
 
+	/// <summary>The object schemas after the first <c>$ref</c> of an <c>allOf</c>; the first one names the type.</summary>
+	private List<ComposedType>? GetComposedTypes(OpenApiSchemaReference[] refSchemas)
+	{
+		var composed = new List<ComposedType>();
+		var primaryName = SchemaHelpers.FormatSchemaName(refSchemas[0].Reference.Id ?? "");
+		foreach (var reference in refSchemas.Skip(1))
+		{
+			var name = SchemaHelpers.FormatSchemaName(reference.Reference.Id ?? "");
+			var target = ResolveSchema(reference) ?? reference;
+			if (
+				string.IsNullOrEmpty(name)
+				|| name == primaryName
+				|| target.Enum is { Count: > 0 }
+				|| ClassifyNamedSchema(name, target).IsPrimitiveAlias
+			)
+				continue;
+			if (composed.All(c => c.Name != name))
+				composed.Add(new ComposedType(name, IsLinkedType(name)));
+		}
+		return composed.Count > 0 ? composed : null;
+	}
+
 	/// <summary>Each object variant carries the shared base members, so it expands to base plus its own properties.</summary>
 	private TypeInfo ClassifyAllOfUnion(AllOfUnion split)
 	{

src/Elastic.ApiExplorer/Model/TypeInfo.cs

@@ -12,6 +12,9 @@ namespace Elastic.ApiExplorer.Model;
 /// </summary>
 public record UnionOption(string Name, string? Ref, bool IsObject, IOpenApiSchema? Schema);
 
+/// <summary>A named schema merged into a type through <c>allOf</c>, beyond the one that names the type.</summary>
+public record ComposedType(string Name, bool HasLink);
+
 /// <summary>
 /// Unified type information record used by both OperationView and SchemaView.
 /// Contains all metadata needed for rendering schema types.
@@ -31,6 +34,7 @@ public record UnionOption(string Name, string? Ref, bool IsObject, IOpenApiSchem
 /// <param name="EnumValues">Every literal the value can take, from <see cref="SchemaAnalyzer.GetEnumValues"/>; set for unions and arrays of enums too.</param>
 /// <param name="UnionOptions">String array of union option names for display.</param>
 /// <param name="ArrayItemType">The primitive item type for arrays of primitives.</param>
+/// <param name="AlsoIncludes">Further named schemas an <c>allOf</c> merges in after the first <c>$ref</c>, which names the type.</param>
 public record TypeInfo(
 	string TypeName,
 	string? SchemaRef,
@@ -46,5 +50,6 @@ public record TypeInfo(
 	bool IsUnion = false,
 	string[]? EnumValues = null,
 	string[]? UnionOptions = null,
-	string? ArrayItemType = null
+	string? ArrayItemType = null,
+	List<ComposedType>? AlsoIncludes = null
 );

tests/Elastic.ApiExplorer.Tests/ApiPropertyTreeBuilderTests.cs

@@ -742,4 +742,71 @@ public async Task BuildPropertyList_AllOfWithOneOfMember_ExpandsVariantsSharingB
 				File.Delete(path);
 		}
 	}
+
+	[Test]
+	public async Task BuildPropertyList_AllOfWithSeveralRefs_ListsTheOtherSchemasAsAlsoIncludes()
+	{
+		var json =
+			"""
+			{
+			  "openapi": "3.0.3",
+			  "info": { "title": "t", "version": "1" },
+			  "paths": {},
+			  "components": {
+			    "schemas": {
+			      "Base": { "type": "object", "properties": { "id": { "type": "string" } } },
+			      "Timestamps": { "type": "object", "properties": { "created": { "type": "string" } } },
+			      "Mode": { "type": "string", "enum": ["a", "b"] },
+			      "Holder": {
+			        "type": "object",
+			        "properties": {
+			          "merged": {
+			            "allOf": [
+			              { "$ref": "#/components/schemas/Base" },
+			              { "$ref": "#/components/schemas/Timestamps" },
+			              { "$ref": "#/components/schemas/Mode" }
+			            ]
+			          },
+			          "repeated": {
+			            "allOf": [
+			              { "$ref": "#/components/schemas/Base" },
+			              { "$ref": "#/components/schemas/Base" },
+			              { "$ref": "#/components/schemas/Timestamps" }
+			            ]
+			          },
+			          "single": { "allOf": [ { "$ref": "#/components/schemas/Base" } ] }
+			        }
+			      }
+			    }
+			  }
+			}
+			""";
+		var path = Path.Join(Path.GetTempPath(), $"allof-multi-{Guid.NewGuid():N}.json");
+		await File.WriteAllTextAsync(path, json, TestContext.Current!.Execution.CancellationToken);
+		try
+		{
+			var loaded = await OpenApiDocument.LoadAsync(
+				path,
+				new OpenApiReaderSettings { LeaveStreamOpen = false },
+				TestContext.Current!.Execution.CancellationToken
+			);
+			var document = loaded.Document!;
+			var builder = new ApiPropertyTreeBuilder(
+				document,
+				new PropertyDisplayOptions { RenderMarkdown = s => new HtmlString($"<p>{s}</p>"), ApiRootUrl = "/api/doc/fixture" }
+			);
+
+			var list = builder.BuildPropertyList(document.Components!.Schemas!["Holder"], new PropertyTreeScope { Prefix = "" });
+
+			var merged = list!.Items.Single(p => p.Name == "merged");
+			merged.AlsoIncludes.Select(t => t.TypeName).Should().Equal("Timestamps");
+			list.Items.Single(p => p.Name == "repeated").AlsoIncludes.Select(t => t.TypeName).Should().Equal("Timestamps");
+			list.Items.Single(p => p.Name == "single").AlsoIncludes.Should().BeEmpty();
+		}
+		finally
+		{
+			if (File.Exists(path))
+				File.Delete(path);
+		}
+	}
 }