Merge pull request #121 from Microsoft/dm/empty-collections

Added missing collection instantiations

Author: darrelmiller

src/Microsoft.OpenApi.Readers/V2/OpenApiDocumentDeserializer.cs

@@ -40,20 +40,36 @@ internal static partial class OpenApiV2Deserializer
             {"paths", (o, n) => o.Paths = LoadPaths(n)},
             {
                 "definitions",
-                (o, n) => o.Components.Schemas = n.CreateMapWithReference(
+                (o, n) => {
+                    o.Components = new OpenApiComponents();
+                    o.Components.Schemas = n.CreateMapWithReference(
                     ReferenceType.Schema,
                     "#/definitions/",
-                    LoadSchema)
+                    LoadSchema);
+                    }
             },
             {
                 "parameters",
-                (o, n) => o.Components.Parameters = n.CreateMapWithReference(
+                (o, n) => {
+                    o.Components = new OpenApiComponents();
+                    o.Components.Parameters = n.CreateMapWithReference(
                     ReferenceType.Parameter,
                     "#/parameters/",
-                    LoadParameter)
+                    LoadParameter);
+                    }
+            },
+            {
+                "responses", (o, n) => {
+                o.Components = new OpenApiComponents();
+                o.Components.Responses = n.CreateMap(LoadResponse);
+                }
+            },
+            {
+                "securityDefinitions", (o, n) => {
+                o.Components = new OpenApiComponents();
+                o.Components.SecuritySchemes = n.CreateMap(LoadSecurityScheme);
+                }
             },
-            {"responses", (o, n) => o.Components.Responses = n.CreateMap(LoadResponse)},
-            {"securityDefinitions", (o, n) => o.Components.SecuritySchemes = n.CreateMap(LoadSecurityScheme)},
             {"security", (o, n) => o.SecurityRequirements = n.CreateList(LoadSecurityRequirement)},
             {"tags", (o, n) => o.Tags = n.CreateList(LoadTag)},
             {"externalDocs", (o, n) => o.ExternalDocs = LoadExternalDocs(n)}

src/Microsoft.OpenApi/Models/OpenApiPathItem.cs

@@ -46,7 +46,7 @@ public class OpenApiPathItem : IOpenApiSerializable, IOpenApiExtensible
         /// <summary>
         /// This object MAY be extended with Specification Extensions.
         /// </summary>
-        public IDictionary<string, IOpenApiAny> Extensions { get; set; }
+        public IDictionary<string, IOpenApiAny> Extensions { get; set; } = new Dictionary<string, IOpenApiAny>();
 
         /// <summary>
         /// Add one operation into this path item.

src/Microsoft.OpenApi/Writers/OpenApiWriterExtensions.cs

@@ -7,6 +7,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.OpenApi.Interfaces;
+using System.Collections;
 
 namespace Microsoft.OpenApi.Writers
 {
@@ -123,6 +124,11 @@ public static void WriteOptionalObject<T>(
         {
             if (value != null)
             {
+                IEnumerable values = value as IEnumerable;
+                if (values != null && !values.GetEnumerator().MoveNext() )
+                {
+                    return;  // Don't render optional empty collections
+                }
                 writer.WriteRequiredObject(name, value, action);
             }
         }

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

@@ -47,12 +47,18 @@
     <None Update="V2Tests\Samples\basic.v3.yaml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="V2Tests\Samples\definitions.v3.yaml">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Update="V2Tests\Samples\host.v2.yaml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
     <None Update="V2Tests\Samples\host.v3.yaml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="V2Tests\Samples\definitions.v2.yaml">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Update="V2Tests\Samples\minimal.v3.yaml">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>

test/Microsoft.OpenApi.Readers.Tests/V2Tests/ComparisonTests.cs

@@ -18,6 +18,7 @@ public class ComparisonTests
         [Theory]
         [InlineData("minimal")]
         [InlineData("basic")]
+        //[InlineData("definitions")]  //Currently broken due to V3 references not behaving the same as V2
         public void EquivalentV2AndV3DocumentsShouldProductEquivalentObjects(string fileName)
         {
             using (var streamV2 = File.OpenRead(Path.Combine(SampleFolderPath, $"{fileName}.v2.yaml")))

test/Microsoft.OpenApi.Readers.Tests/V2Tests/Samples/definitions.v2.yaml

@@ -0,0 +1,17 @@
+swagger: 2.0
+info: 
+  title: This is a simple example
+  version: 1.0.0
+paths:
+  '/':
+    get:
+      produces:
+        - application/json
+      200: 
+        description: Ok
+        schema:
+          $ref: '#/definitions/simple'
+definitions:
+  simple:
+    type: string
+        

test/Microsoft.OpenApi.Readers.Tests/V2Tests/Samples/definitions.v3.yaml

@@ -0,0 +1,18 @@
+openapi: 3.0
+info: 
+  title: This is a simple example
+  version: 1.0.0
+paths:
+  '/':
+    get:
+      200: 
+        description: Ok
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/simple'
+components:
+  schemas:
+    simple:
+      type: string
+