upstream main sync to feature branch

.github/workflows/codeql-analysis.yml

@@ -29,7 +29,7 @@ jobs:
 
       - name: Initialize CodeQL
         id: init_codeql
-        uses: github/codeql-action/init@v3
+        uses: github/codeql-action/init@v4
         with:
           queries: security-and-quality
 
@@ -49,6 +49,6 @@ jobs:
 
       - name: Perform CodeQL Analysis
         id: analyze_codeql
-        uses: github/codeql-action/analyze@v3
+        uses: github/codeql-action/analyze@v4
 
 # Built with ❤ by [Pipeline Foundation](https://pipeline.foundation)

.release-please-manifest.json

@@ -1,3 +1,3 @@
 {
-  ".": "2.3.4"
+  ".": "2.3.6"
 }

CHANGELOG.md

@@ -1,5 +1,20 @@
 # Changelog
 
+## [2.3.6](https://github.com/microsoft/OpenAPI.NET/compare/v2.3.5...v2.3.6) (2025-10-20)
+
+
+### Bug Fixes
+
+* a bug where empty collections would not be serialized for default values ([4c4d257](https://github.com/microsoft/OpenAPI.NET/commit/4c4d257c0cf10d1742fae9f3961e4a6242c0ce1d))
+
+## [2.3.5](https://github.com/microsoft/OpenAPI.NET/compare/v2.3.4...v2.3.5) (2025-10-14)
+
+
+### Bug Fixes
+
+* use settings for terse output in serialization extension methods ([246039b](https://github.com/microsoft/OpenAPI.NET/commit/246039bfa8a16c042a10a87126289de82d18b321))
+* use settings for terse output in serialization extension methods ([8b91278](https://github.com/microsoft/OpenAPI.NET/commit/8b912788ef18b44a083d3fd2a1d6e25c9e6e17cb))
+
 ## [2.3.4](https://github.com/microsoft/OpenAPI.NET/compare/v2.3.3...v2.3.4) (2025-10-06)
 
 

Directory.Build.props

@@ -12,7 +12,7 @@
     <PackageProjectUrl>https://github.com/Microsoft/OpenAPI.NET</PackageProjectUrl>
     <Copyright>© Microsoft Corporation. All rights reserved.</Copyright>
     <PackageTags>OpenAPI .NET</PackageTags>
-    <Version>2.3.4</Version>
+    <Version>2.3.6</Version>
   </PropertyGroup>
   <!-- https://github.com/clairernovotny/DeterministicBuilds#deterministic-builds -->
   <PropertyGroup Condition="'$(TF_BUILD)' == 'true'">

global.json

@@ -1,5 +1,5 @@
 {
   "sdk": {
-    "version": "8.0.414"
+    "version": "8.0.415"
   }
 }

performance/resultsComparer/resultsComparer.csproj

@@ -8,12 +8,12 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="9.0.10" />
     <PackageReference Include="System.CommandLine" Version="2.0.0-beta5.25306.1" />
-    <PackageReference Include="system.text.json" Version="9.0.9" />
+    <PackageReference Include="system.text.json" Version="9.0.10" />
   </ItemGroup>
 
 </Project>

src/Microsoft.OpenApi.Hidi/Microsoft.OpenApi.Hidi.csproj

@@ -29,10 +29,10 @@
 
   <ItemGroup>
     <PackageReference Include="Humanizer.Core" Version="2.14.1" />
-    <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.9" />
-    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.10" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Debug" Version="9.0.10" />
     <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="17.14.15">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>

src/Microsoft.OpenApi.Hidi/OpenApiService.cs

@@ -192,16 +192,17 @@ private static async Task WriteOpenApiAsync(HidiOptions options, string openApiF
                 using var outputStream = options.Output.Create();
                 using var textWriter = new StreamWriter(outputStream);
 
-                var settings = new OpenApiWriterSettings
+                var settings = new OpenApiJsonWriterSettings
                 {
                     InlineLocalReferences = options.InlineLocal,
-                    InlineExternalReferences = options.InlineExternal
+                    InlineExternalReferences = options.InlineExternal,
+                    Terse = options.TerseOutput
                 };
 #pragma warning disable CA1308
                 IOpenApiWriter writer = openApiFormat.ToLowerInvariant() switch
 #pragma warning restore CA1308
                 {
-                    OpenApiConstants.Json => options.TerseOutput ? new(textWriter, settings, options.TerseOutput) : new OpenApiJsonWriter(textWriter, settings, false),
+                    OpenApiConstants.Json => new OpenApiJsonWriter(textWriter, settings),
                     OpenApiConstants.Yaml => new OpenApiYamlWriter(textWriter, settings),
                     _ => throw new ArgumentException("Unknown format"),
                 };

src/Microsoft.OpenApi.Workbench/Microsoft.OpenApi.Workbench.csproj

@@ -13,7 +13,7 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="Microsoft.Windows.Compatibility" Version="9.0.9" />
+    <PackageReference Include="Microsoft.Windows.Compatibility" Version="9.0.10" />
   </ItemGroup>
   <ItemGroup>
     <Resource Include="Themes\Metro\HowToApplyTheme.txt" />

src/Microsoft.OpenApi/Extensions/OpenApiSerializableExtensions.cs

@@ -88,7 +88,8 @@ public static Task SerializeAsync<T>(
 
             IOpenApiWriter writer = format.ToLowerInvariant() switch
             {
-                OpenApiConstants.Json => new OpenApiJsonWriter(streamWriter, settings, false),
+                OpenApiConstants.Json when settings is OpenApiJsonWriterSettings jsonSettings => new OpenApiJsonWriter(streamWriter, jsonSettings),
+                OpenApiConstants.Json => new OpenApiJsonWriter(streamWriter, settings),
                 OpenApiConstants.Yaml => new OpenApiYamlWriter(streamWriter, settings),
                 _ => throw new OpenApiException(string.Format(SRResource.OpenApiFormatNotSupported, format)),
             };

src/Microsoft.OpenApi/Writers/OpenApiJsonWriter.cs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license.
 
+using System;
+using System.ComponentModel;
 using System.IO;
 
 namespace Microsoft.OpenApi
@@ -14,7 +16,17 @@ public class OpenApiJsonWriter : OpenApiWriterBase
         /// Initializes a new instance of the <see cref="OpenApiJsonWriter"/> class.
         /// </summary>
         /// <param name="textWriter">The text writer.</param>
-        public OpenApiJsonWriter(TextWriter textWriter) : base(textWriter, null)
+        public OpenApiJsonWriter(TextWriter textWriter) : this(textWriter, (OpenApiWriterSettings?)null)
+        {
+			// this constructor is kept for binary compatibility
+            // TODO remove in next major version and make the settings an optional parameter in the other constructor
+		}
+        /// <summary>
+        /// Initializes a new instance of the <see cref="OpenApiJsonWriter"/> class.
+        /// </summary>
+        /// <param name="settings">Settings for controlling how the OpenAPI document will be written out.</param>
+        /// <param name="textWriter">The text writer.</param>
+        public OpenApiJsonWriter(TextWriter textWriter, OpenApiWriterSettings? settings) : base(textWriter, settings ?? new OpenApiJsonWriterSettings())
         {
         }
 
@@ -34,9 +46,13 @@ public OpenApiJsonWriter(TextWriter textWriter, OpenApiJsonWriterSettings settin
         /// <param name="textWriter">The text writer.</param>
         /// <param name="settings">Settings for controlling how the OpenAPI document will be written out.</param>
         /// <param name="terseOutput"> Setting for allowing the JSON emitted to be in terse format.</param>
-        public OpenApiJsonWriter(TextWriter textWriter, OpenApiWriterSettings? settings, bool terseOutput = false) : base(textWriter, settings)
+        [Obsolete("Use OpenApiJsonWriter(TextWriter textWriter, OpenApiJsonWriterSettings settings) instead.")]
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public OpenApiJsonWriter(TextWriter textWriter, OpenApiWriterSettings? settings, bool terseOutput) : base(textWriter, settings)
         {
             _produceTerseOutput = terseOutput;
+            // this constructor is kept for binary compatibility, terse information should be read from the settings to avoid fork APIs.
+            // TODO remove in next major version
         }
 
         /// <summary>

src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs

@@ -55,10 +55,7 @@ protected OpenApiWriterBase(TextWriter textWriter, OpenApiWriterSettings? settin
             Writer.NewLine = "\n";
 
             Scopes = new();
-            if (settings == null)
-            {
-                settings = new();
-            }
+            settings ??= new();
             Settings = settings;
         }
 

src/Microsoft.OpenApi/Writers/OpenApiWriterExtensions.cs

@@ -141,9 +141,9 @@ public static void WriteOptionalObject<T>(
         {
             if (value != null)
             {
-                if (value is IEnumerable values && !values.GetEnumerator().MoveNext())
+                if (value is IEnumerable values && value is not JsonArray && !values.GetEnumerator().MoveNext())
                 {
-                    return; // Don't render optional empty collections
+                    return; // Don't render optional empty collections except for the Default properties which are JsonArray
                 }
 
                 writer.WriteRequiredObject(name, value, action);

test/Microsoft.OpenApi.Hidi.Tests/Microsoft.OpenApi.Hidi.Tests.csproj

@@ -17,7 +17,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
     <PackageReference Include="xunit" Version="2.9.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" PrivateAssets="all" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" PrivateAssets="all" />
     <PackageReference Include="coverlet.collector" Version="6.0.4" PrivateAssets="all" />
   </ItemGroup>
 

test/Microsoft.OpenApi.Readers.Tests/Microsoft.OpenApi.Readers.Tests.csproj

@@ -19,9 +19,9 @@
         <PackageReference Include="coverlet.msbuild" Version="6.0.4" PrivateAssets="all" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
         <PackageReference Include="FluentAssertions" Version="7.2.0" />
-        <PackageReference Include="system.text.json" Version="9.0.9" />
+        <PackageReference Include="system.text.json" Version="9.0.10" />
         <PackageReference Include="xunit" Version="2.9.3" />
-        <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" PrivateAssets="all" />
+        <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" PrivateAssets="all" />
     </ItemGroup>
 
     <ItemGroup>

test/Microsoft.OpenApi.Readers.Tests/V31Tests/OpenApiSchemaTests.cs

@@ -315,6 +315,40 @@ public void CloningSchemaWithExamplesAndEnumsShouldSucceed()
             Assert.Equivalent(6, clone.Default.GetValue<int>());
         }
 
+        [Fact]
+        public void DefaultEmptyCollectionShouldRoundTrip()
+        {
+            // Given
+            var serializedSchema =
+            """
+            {
+                "type": "array",
+                "items": {
+                    "type": "string",
+                    "default": []
+                }
+            }
+            """;
+            using var textWriter = new StringWriter();
+            var writer = new OpenApiJsonWriter(textWriter);
+
+            // When
+            var schema = OpenApiModelFactory.Parse<OpenApiSchema>(serializedSchema, OpenApiSpecVersion.OpenApi3_1, new(), out _, "json", SettingsFixture.ReaderSettings);
+
+            var deserializedArray = Assert.IsType<JsonArray>(schema.Items.Default);
+            Assert.Empty(deserializedArray);
+
+            schema.SerializeAsV31(writer);
+            var roundTrippedSchema = textWriter.ToString();
+
+            // Then
+            var parsedResult = JsonNode.Parse(roundTrippedSchema);
+            var parsedExpected = JsonNode.Parse(serializedSchema);
+            Assert.True(JsonNode.DeepEquals(parsedExpected, parsedResult));
+            var resultingArray = Assert.IsType<JsonArray>(parsedResult["items"]?["default"]);
+            Assert.Empty(resultingArray);
+        }
+
         [Fact]
         public async Task SerializeV31SchemaWithMultipleTypesAsV3Works()
         {

test/Microsoft.OpenApi.Tests/Extensions/OpenApiSerializableExtensionsTests.cs

@@ -0,0 +1,93 @@
+using System.IO;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace Microsoft.OpenApi.Tests.Extensions;
+
+public class OpenApiSerializableExtensionsTests
+{
+    [Fact]
+    public async Task UsesTheTerseOutputInformationFromSettingsTrue()
+    {
+        var parameter = new OpenApiParameter
+        {
+            Name = "param1",
+            In = ParameterLocation.Query,
+            Description = "A sample parameter",
+            Required = false,
+            Schema = new OpenApiSchema
+            {
+                Type = JsonSchemaType.String
+            }
+        };
+
+        var settings = new OpenApiJsonWriterSettings
+        {
+            Terse = true
+        };
+
+        using var stream = new MemoryStream();
+        await parameter.SerializeAsync(stream, OpenApiSpecVersion.OpenApi3_1, OpenApiConstants.Json, settings);
+
+        stream.Position = 0;
+        using var reader = new StreamReader(stream);
+        var output = await reader.ReadToEndAsync();
+
+        Assert.Equal("{\"name\":\"param1\",\"in\":\"query\",\"description\":\"A sample parameter\",\"schema\":{\"type\":\"string\"}}", output);
+    }
+
+    [Fact]
+    public async Task UsesTheTerseOutputInformationFromSettingsFalse()
+    {
+        var parameter = new OpenApiParameter
+        {
+            Name = "param1",
+            In = ParameterLocation.Query,
+            Description = "A sample parameter",
+            Required = false,
+            Schema = new OpenApiSchema
+            {
+                Type = JsonSchemaType.String
+            }
+        };
+
+        var settings = new OpenApiJsonWriterSettings
+        {
+            Terse = false
+        };
+
+        using var stream = new MemoryStream();
+        await parameter.SerializeAsync(stream, OpenApiSpecVersion.OpenApi3_1, OpenApiConstants.Json, settings);
+
+        stream.Position = 0;
+        using var reader = new StreamReader(stream);
+        var output = await reader.ReadToEndAsync();
+
+        Assert.Equal("{\n  \"name\": \"param1\",\n  \"in\": \"query\",\n  \"description\": \"A sample parameter\",\n  \"schema\": {\n    \"type\": \"string\"\n  }\n}", output);
+    }
+
+    [Fact]
+    public async Task UsesTheTerseOutputInformationFromSettingsNoSettings()
+    {
+        var parameter = new OpenApiParameter
+        {
+            Name = "param1",
+            In = ParameterLocation.Query,
+            Description = "A sample parameter",
+            Required = false,
+            Schema = new OpenApiSchema
+            {
+                Type = JsonSchemaType.String
+            }
+        };
+
+        using var stream = new MemoryStream();
+        await parameter.SerializeAsync(stream, OpenApiSpecVersion.OpenApi3_1, OpenApiConstants.Json, null);
+
+        stream.Position = 0;
+        using var reader = new StreamReader(stream);
+        var output = await reader.ReadToEndAsync();
+
+        Assert.Equal("{\n  \"name\": \"param1\",\n  \"in\": \"query\",\n  \"description\": \"A sample parameter\",\n  \"schema\": {\n    \"type\": \"string\"\n  }\n}", output);
+    }
+}

test/Microsoft.OpenApi.Tests/Microsoft.OpenApi.Tests.csproj

@@ -13,12 +13,12 @@
     <PackageReference Include="FluentAssertions" Version="7.2.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.0.0" />
     <PackageReference Include="Moq" Version="4.20.72" />
-    <PackageReference Include="System.Text.Json" Version="9.0.9" />
-    <PackageReference Include="Verify.Xunit" Version="30.11.0" />
+    <PackageReference Include="System.Text.Json" Version="9.0.10" />
+    <PackageReference Include="Verify.Xunit" Version="31.0.1" />
     <PackageReference Include="xunit" Version="2.9.3" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.4" PrivateAssets="all" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5" PrivateAssets="all" />
     <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
-    <PackageReference Include="PublicApiGenerator" Version="11.4.6" />
+    <PackageReference Include="PublicApiGenerator" Version="11.5.0" />
   </ItemGroup>
 
   <ItemGroup>

test/Microsoft.OpenApi.Tests/PublicApi/PublicApi.approved.txt

@@ -795,7 +795,10 @@ namespace Microsoft.OpenApi
     {
         public OpenApiJsonWriter(System.IO.TextWriter textWriter) { }
         public OpenApiJsonWriter(System.IO.TextWriter textWriter, Microsoft.OpenApi.OpenApiJsonWriterSettings settings) { }
-        public OpenApiJsonWriter(System.IO.TextWriter textWriter, Microsoft.OpenApi.OpenApiWriterSettings? settings, bool terseOutput = false) { }
+        public OpenApiJsonWriter(System.IO.TextWriter textWriter, Microsoft.OpenApi.OpenApiWriterSettings? settings) { }
+        [System.Obsolete("Use OpenApiJsonWriter(TextWriter textWriter, OpenApiJsonWriterSettings settings) " +
+            "instead.")]
+        public OpenApiJsonWriter(System.IO.TextWriter textWriter, Microsoft.OpenApi.OpenApiWriterSettings? settings, bool terseOutput) { }
         protected override int BaseIndentation { get; }
         public override void WriteEndArray() { }
         public override void WriteEndObject() { }