build(csharp): prepare NuGet package for nuget.org publishing (#668)

* build(csharp): rename NuGet package to Microsoft.Regorus

Align the NuGet package identity with the Microsoft.Regorus
namespace and the Microsoft.* reserved prefix on nuget.org
in preparation for publishing the package.

- Add explicit <PackageId>Microsoft.Regorus</PackageId>
- Update PackageVersion in Directory.Packages.props
- Update version bump regex for new package name

* build(csharp): default to ProjectReference for in-repo consumers

Use ProjectReference for Regorus.Tests, Benchmarks, TestApp,
and TargetExampleApp so that local development does not require
a pre-built .nupkg. PackageReference mode remains available via
/p:UsePackageReference=true for validating the packaged NuGet.

* build(csharp): add nuget.config with source mapping and xtask integration

Add explicit NuGet configuration to ensure in-repo builds always
resolve Microsoft.Regorus from the locally built package, even
after the package is published on nuget.org.

- Add nuget.config with <clear/> and packageSourceMapping
- Update xtask to copy .nupkg into local-packages/ directory
- Pass /p:UsePackageReference=true from xtask for CI testing
- Add restore validation step to the xtask test flow
- Add .gitignore for the local-packages directory

bindings/csharp/.gitignore

@@ -0,0 +1 @@
+local-packages/

bindings/csharp/Benchmarks/Benchmarks.csproj

@@ -8,15 +8,15 @@
   <PropertyGroup>
     <!-- If the environment variable is set (such as in a Github Action run), append the suffix to the version number -->
     <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
+    <UsePackageReference Condition="'$(UsePackageReference)' == ''">false</UsePackageReference>
   </PropertyGroup>
 
-  <PropertyGroup>
-    <!-- If the environment variable is set (such as in a Github Action run), append the suffix to the version number -->
-    <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
-  </PropertyGroup>
+  <ItemGroup Condition="'$(UsePackageReference)' != 'true'">
+    <ProjectReference Include="../Regorus/Regorus.csproj" />
+  </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Regorus" />
+  <ItemGroup Condition="'$(UsePackageReference)' == 'true'">
+    <PackageReference Include="Microsoft.Regorus" />
   </ItemGroup>
 
   <ItemGroup>

bindings/csharp/Directory.Packages.props

@@ -7,7 +7,7 @@
 
   <ItemGroup>
     <!-- Centralize Regorus package version with optional CI suffix -->
-    <PackageVersion Include="Regorus" Version="$(RegorusPackageVersion)$(RegorusPackageVersionSuffix)" />
+    <PackageVersion Include="Microsoft.Regorus" Version="$(RegorusPackageVersion)$(RegorusPackageVersionSuffix)" />
     <PackageVersion Include="MSTest" Version="3.8.2" />
     <PackageVersion Include="System.Text.Json" Version="8.0.5" />
     <PackageVersion Include="YamlDotNet" Version="13.7.0" />

bindings/csharp/Regorus.Tests/Regorus.Tests.csproj

@@ -12,6 +12,7 @@
   <PropertyGroup>
     <!-- If the environment variable is set (such as in a Github Action run), append the suffix to the version number -->
     <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
+    <UsePackageReference Condition="'$(UsePackageReference)' == ''">false</UsePackageReference>
   </PropertyGroup>
 
   <ItemGroup>
@@ -23,8 +24,12 @@
     <PackageReference Include="YamlDotNet" />
   </ItemGroup>
 
-  <ItemGroup>
-    <PackageReference Include="Regorus" />
+  <ItemGroup Condition="'$(UsePackageReference)' != 'true'">
+    <ProjectReference Include="../Regorus/Regorus.csproj" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(UsePackageReference)' == 'true'">
+    <PackageReference Include="Microsoft.Regorus" />
   </ItemGroup>
 
   <ItemGroup>

bindings/csharp/Regorus/Regorus.csproj

@@ -2,6 +2,7 @@
 
     <PropertyGroup>
         <OutputType>Library</OutputType>
+        <PackageId>Microsoft.Regorus</PackageId>
         <RootNamespace>Microsoft.Regorus</RootNamespace>
         <TargetFrameworks>netstandard2.0;netstandard2.1</TargetFrameworks>
         <AllowUnsafeBlocks>true</AllowUnsafeBlocks>

bindings/csharp/TargetExampleApp/TargetExampleApp.csproj

@@ -11,15 +11,15 @@
   <PropertyGroup>
     <!-- If the environment variable is set (such as in a Github Action run), append the suffix to the version number -->
     <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
-    <UseLocalRegorus Condition="'$(UseLocalRegorus)' == ''">false</UseLocalRegorus>
+    <UsePackageReference Condition="'$(UsePackageReference)' == ''">false</UsePackageReference>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(UseLocalRegorus)' == 'true'">
+  <ItemGroup Condition="'$(UsePackageReference)' != 'true'">
     <ProjectReference Include="../Regorus/Regorus.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(UseLocalRegorus)' != 'true'">
-    <PackageReference Include="Regorus" />
+  <ItemGroup Condition="'$(UsePackageReference)' == 'true'">
+    <PackageReference Include="Microsoft.Regorus" />
   </ItemGroup>
 
   <ItemGroup>

bindings/csharp/TestApp/TestApp.csproj

@@ -13,14 +13,14 @@
   <PropertyGroup>
     <!-- Allow CI to append the version suffix for locally built packages -->
     <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
-    <UseLocalRegorus Condition="'$(UseLocalRegorus)' == ''">false</UseLocalRegorus>
+    <UsePackageReference Condition="'$(UsePackageReference)' == ''">false</UsePackageReference>
   </PropertyGroup>
 
-  <ItemGroup Condition="'$(UseLocalRegorus)' == 'true'">
+  <ItemGroup Condition="'$(UsePackageReference)' != 'true'">
     <ProjectReference Include="../Regorus/Regorus.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(UseLocalRegorus)' != 'true'">
-    <PackageReference Include="Regorus" />
+  <ItemGroup Condition="'$(UsePackageReference)' == 'true'">
+    <PackageReference Include="Microsoft.Regorus" />
   </ItemGroup>
 </Project>

bindings/csharp/nuget.config

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+    <!-- Local source populated by the xtask with the freshly built .nupkg -->
+    <add key="local" value="local-packages" />
+  </packageSources>
+
+  <!-- NuGet source mapping: the most-specific pattern wins, so Microsoft.Regorus
+       always resolves exclusively from "local" even though nuget.org has "*".
+       See https://learn.microsoft.com/nuget/consume-packages/package-source-mapping -->
+  <packageSourceMapping>
+    <packageSource key="nuget.org">
+      <package pattern="*" />
+    </packageSource>
+    <packageSource key="local">
+      <package pattern="Microsoft.Regorus" />
+    </packageSource>
+  </packageSourceMapping>
+</configuration>