fix: readd netstandard target to ensure source generator compat

also added polyfills for language features missing in netstandard2.0

Author: VisualBean

Common.Build.props

@@ -2,7 +2,7 @@
   <!-- Common Properties used by all assemblies -->
   <PropertyGroup>
     <LangVersion>10</LangVersion>
-    <TargetFrameworks>netstandard2.1;net8</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net8</TargetFrameworks>
     <ImplicitUsings>disable</ImplicitUsings>
     <Company>ByteBard</Company>
     <PackageProjectUrl>https://github.com/ByteBardOrg/AsyncAPI.NET</PackageProjectUrl>

src/ByteBard.AsyncAPI.Readers/ByteBard.AsyncAPI.Readers.csproj

@@ -14,7 +14,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="System.Text.Json" Version="9.0.1" Condition="'$(TargetFramework)' == 'netstandard2.1'" />
+    <PackageReference Include="System.Text.Json" Version="9.0.1" Condition="'$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'netstandard2.1'" />
     <PackageReference Include="YamlDotNet" Version="13.0.1" />
   </ItemGroup>
 

src/ByteBard.AsyncAPI.Readers/V2/AsyncApiDocumentDeserializer.cs

@@ -88,7 +88,7 @@ private static void SetOperations(ParsingContext context, AsyncApiDocument docum
                 if (operation.Value.Channel != null)
                 {
                     var messages = context.GetFromTempStorage<Dictionary<string, AsyncApiMessageReference>>(TempStorageKeys.OperationMessageReferences, operation.Value);
-                    var operationChannelFragmentKey = operation.Value.Channel.Reference.Reference.Split("/")[^1];
+                    var operationChannelFragmentKey = operation.Value.Channel.Reference.Reference.Split('/').Last();
                     var channel = document.Channels.FirstOrDefault(channel => channel.Key == operationChannelFragmentKey);
                     if (channel.Value == null)
                     {

src/ByteBard.AsyncAPI.Readers/V2/AsyncApiOperationDeserializer.cs

@@ -1,6 +1,7 @@
 namespace ByteBard.AsyncAPI.Readers
 {
     using System.Collections.Generic;
+    using System.Linq;
     using System.Threading;
     using ByteBard.AsyncAPI.Extensions;
     using ByteBard.AsyncAPI.Models;
@@ -47,7 +48,7 @@ private static KeyValuePair<string, AsyncApiMessage> GetMessage(ParseNode node)
             var message = LoadMessage(node);
             if (message is AsyncApiMessageReference reference)
             {
-                key = reference.Reference.Reference.Split("/")[^1];
+                key = reference.Reference.Reference.Split('/').Last();
             }
             else if (messageNode["messageId"] != null)
             {

src/ByteBard.AsyncAPI/ByteBard.AsyncAPI.csproj

@@ -12,7 +12,7 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="System.Text.Json" Version="9.0.1" Condition="'$(TargetFramework)' == 'netstandard2.1'" />
+    <PackageReference Include="System.Text.Json" Version="9.0.1" Condition="'$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'netstandard2.1'" />
 
 	  <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleTo">
 		  <_Parameter1>$(MSBuildProjectName).Tests</_Parameter1>

src/ByteBard.AsyncAPI/Models/References/AsyncApiSecuritySchemeReference.cs

@@ -88,9 +88,7 @@ public void SerializeAsSecurityRequirement(IAsyncApiWriter writer)
             this.Reference.Workspace = writer.Workspace;
 
             writer.WriteStartObject();
-
-            writer.WritePropertyName(this.Reference.FragmentId.Split("/")[^1]);
-
+            writer.WritePropertyName(this.Reference.FragmentId.Split('/').Last());
             writer.WriteStartArray();
 
             if (this.Scopes.Any())

src/ByteBard.AsyncAPI/Polyfill.cs

@@ -0,0 +1,34 @@
+namespace ByteBard.AsyncAPI;
+
+using System.Collections.Generic;
+
+public static class PolyfillExtensions
+{
+#if NETSTANDARD2_0
+    public static HashSet<T> ToHashSet<T>(this IEnumerable<T> source)
+    {
+        return new HashSet<T>(source);
+    }
+
+    public static bool TryAdd<TKey, TValue>(this IDictionary<TKey, TValue> source, TKey key, TValue value)
+    {
+        if (source.ContainsKey(key))
+        {
+            return false;
+        }
+
+        source.Add(key, value);
+        return true;
+    }
+
+    public static TValue GetValueOrDefault<TKey, TValue>(this IDictionary<TKey, TValue> source, TKey key)
+    {
+        if (source.ContainsKey(key))
+        {
+            return source[key];
+        }
+        
+        return default(TValue);
+    }
+#endif
+}