allow to install multiple versions of the same packages

src/Orc.NuGetExplorer.Tests/PublicApiFacts.Orc_NuGetExplorer_HasNoBreakingChanges_Async.verified.txt

@@ -428,6 +428,23 @@ namespace Orc.NuGetExplorer
         string GetDirectory(string relativeDirectoryName);
         string GetFile(string relativeFilePath);
     }
+    [System.Runtime.CompilerServices.RequiredMember]
+    public class InstallationContext
+    {
+        [System.Obsolete(("Constructors of types with required members are not supported in this version of " +
+            "your compiler."), true)]
+        [System.Runtime.CompilerServices.CompilerFeatureRequired("RequiredMembers")]
+        public InstallationContext() { }
+        public bool AllowMultipleVersions { get; set; }
+        public bool IgnoreMissingPackages { get; set; }
+        [System.Runtime.CompilerServices.RequiredMember]
+        public NuGet.Packaging.Core.PackageIdentity Package { get; set; }
+        public System.Func<NuGet.Packaging.Core.PackageIdentity, bool>? PackagePredicate { get; set; }
+        [System.Runtime.CompilerServices.RequiredMember]
+        public Orc.NuGetExplorer.IExtensibleProject Project { get; set; }
+        [System.Runtime.CompilerServices.RequiredMember]
+        public System.Collections.Generic.IReadOnlyList<NuGet.Protocol.Core.Types.SourceRepository> Repositories { get; set; }
+    }
     public class InstallerResult
     {
         public InstallerResult(System.Collections.Generic.IDictionary<NuGet.Protocol.Core.Types.SourcePackageDependencyInfo, NuGet.Protocol.Core.Types.DownloadResourceResult> downloadResult) { }
@@ -1249,6 +1266,10 @@ namespace Orc.NuGetExplorer.Services
     public interface IPackageInstallationService
     {
         NuGet.Packaging.VersionFolderPathResolver InstallerPathResolver { get; }
+        System.Threading.Tasks.Task<Orc.NuGetExplorer.InstallerResult> InstallAsync(Orc.NuGetExplorer.InstallationContext context, System.Threading.CancellationToken cancellationToken = default);
+        [System.Obsolete(("Use `InstallAsync(InstallationContext context, CancellationToken cancellationToke" +
+            "n = default)` instead. Will be treated as an error from version 6.0.0. Will be r" +
+            "emoved in version 7.0.0."), false)]
         System.Threading.Tasks.Task<Orc.NuGetExplorer.InstallerResult> InstallAsync(NuGet.Packaging.Core.PackageIdentity package, Orc.NuGetExplorer.IExtensibleProject project, System.Collections.Generic.IReadOnlyList<NuGet.Protocol.Core.Types.SourceRepository> repositories, bool ignoreMissingPackages = false, System.Func<NuGet.Packaging.Core.PackageIdentity, bool>? packagePredicate = null, System.Threading.CancellationToken cancellationToken = default);
         System.Threading.Tasks.Task<long?> MeasurePackageSizeFromRepositoryAsync(NuGet.Packaging.Core.PackageIdentity packageIdentity, NuGet.Protocol.Core.Types.SourceRepository sourceRepository);
         System.Threading.Tasks.Task UninstallAsync(NuGet.Packaging.Core.PackageIdentity package, Orc.NuGetExplorer.IExtensibleProject project, System.Collections.Generic.IEnumerable<NuGet.Packaging.PackageReference> installedPackageReferences, System.Func<NuGet.Packaging.Core.PackageIdentity, bool>? packagePredicate = null, System.Threading.CancellationToken cancellationToken = default);

src/Orc.NuGetExplorer/Management/NuGetProjectPackageManager.cs

@@ -240,8 +240,16 @@ public async Task<bool> InstallPackageForProjectAsync(IExtensibleProject project
 
                 return false;
             }
-
-            var installerResults = await _packageInstallationService.InstallAsync(package, project, repositories, project.IgnoreDependencies, packagePredicate, token);
+            var context = new InstallationContext
+            {
+                Project = project,
+                Repositories = repositories,
+                Package = package,
+                PackagePredicate = packagePredicate,
+                AllowMultipleVersions = true
+            };
+
+            var installerResults = await _packageInstallationService.InstallAsync(context, token);
             if (!installerResults.Result.Any())
             {
                 if (showErrors)

src/Orc.NuGetExplorer/Models/InstallationContext.cs

@@ -0,0 +1,17 @@
+namespace Orc.NuGetExplorer;
+
+using System;
+using System.Collections.Generic;
+using System.Threading;
+using NuGet.Packaging.Core;
+using NuGet.Protocol.Core.Types;
+
+public class InstallationContext
+{
+    public required PackageIdentity Package { get; set; }
+    public required IExtensibleProject Project { get; set; }
+    public required IReadOnlyList<SourceRepository> Repositories { get; set; }
+    public bool IgnoreMissingPackages { get; set; }
+    public Func<PackageIdentity, bool>? PackagePredicate { get; set; }
+    public bool AllowMultipleVersions { get; set; } = false;
+}

src/Orc.NuGetExplorer/Services/Interfaces/IPackageInstallationService.cs

@@ -15,7 +15,10 @@ public interface IPackageInstallationService
     /// </summary>
     VersionFolderPathResolver InstallerPathResolver { get; }
 
-    Task<InstallerResult> InstallAsync(
+    Task<InstallerResult> InstallAsync(InstallationContext context, CancellationToken cancellationToken = default);
+
+    [ObsoleteEx(ReplacementTypeOrMember = "InstallAsync(InstallationContext context, CancellationToken cancellationToken = default)", TreatAsErrorFromVersion = "6", RemoveInVersion = "7")]
+    public Task<InstallerResult> InstallAsync(
         PackageIdentity package,
         IExtensibleProject project,
         IReadOnlyList<SourceRepository> repositories,

src/Orc.NuGetExplorer/Services/PackageInstallationService.cs

@@ -3,6 +3,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.IO.Packaging;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -90,6 +91,23 @@ public PackageInstallationService(IServiceLocator serviceLocator,
 
     public VersionFolderPathResolver InstallerPathResolver => _installerPathResolver;
 
+    [ObsoleteEx(ReplacementTypeOrMember = "InstallAsync(InstallationContext context, CancellationToken cancellationToken = default)", TreatAsErrorFromVersion = "6", RemoveInVersion = "7")]
+    public Task<InstallerResult> InstallAsync(PackageIdentity package, IExtensibleProject project, IReadOnlyList<SourceRepository> repositories, bool ignoreMissingPackages = false, Func<PackageIdentity, bool>? packagePredicate = null, CancellationToken cancellationToken = default)
+    {
+        ArgumentNullException.ThrowIfNull(package);
+        ArgumentNullException.ThrowIfNull(project);
+        ArgumentNullException.ThrowIfNull(repositories);
+        var context = new InstallationContext
+        {
+            Package = package,
+            Project = project,
+            Repositories = repositories,
+            IgnoreMissingPackages = ignoreMissingPackages,
+            PackagePredicate = packagePredicate,
+        };
+        return InstallAsync(context, cancellationToken);
+    }
+
     public async Task UninstallAsync(PackageIdentity package, IExtensibleProject project, IEnumerable<PackageReference> installedPackageReferences,
         Func<PackageIdentity, bool>? packagePredicate = null, CancellationToken cancellationToken = default)
     {
@@ -184,17 +202,16 @@ public async Task UninstallAsync(PackageIdentity package, IExtensibleProject pro
     }
 
     [Time]
-    public async Task<InstallerResult> InstallAsync(
-        PackageIdentity package,
-        IExtensibleProject project,
-        IReadOnlyList<SourceRepository> repositories,
-        bool ignoreMissingPackages = false,
-        Func<PackageIdentity, bool>? packagePredicate = null,
-        CancellationToken cancellationToken = default)
+    public async Task<InstallerResult> InstallAsync(InstallationContext context, CancellationToken cancellationToken = default)
     {
-        ArgumentNullException.ThrowIfNull(package);
-        ArgumentNullException.ThrowIfNull(project);
-        ArgumentNullException.ThrowIfNull(repositories);
+        ArgumentNullException.ThrowIfNull(context);
+
+        var project = context.Project;
+        var package = context.Package;
+        var repositories = context.Repositories;
+        var ignoreMissingPackages = context.IgnoreMissingPackages;
+        var packagePredicate = context.PackagePredicate;
+        var allowMultipleVersions = context.AllowMultipleVersions;
 
         try
         {
@@ -235,7 +252,7 @@ public async Task<InstallerResult> InstallAsync(
 
                 var dependencyInfoResources = new DependencyInfoResourceCollection(dependencyResources);
 
-                resolverContext = await ResolveDependenciesAsync(package, targetFramework, PackageIdentityComparer.Default, dependencyInfoResources, 
+                resolverContext = await ResolveDependenciesAsync(package, targetFramework, PackageIdentityComparer.Default, dependencyInfoResources,
                     sourceCacheContext, project, ignoreMissingPackages, packagePredicate, cancellationToken);
 
                 if (resolverContext is null ||
@@ -271,12 +288,20 @@ public async Task<InstallerResult> InstallAsync(
                     throw Log.ErrorAndCreateException<IncompatiblePackageException>($"Package {package} incompatible with project target platform {targetFramework}");
                 }
 
-                // Step 5. Build install list using NuGet Resolver and select available resources. 
-                // Track packages which already installed and make sure only one version of package exists
-                var resolver = new Resolver.PackageResolver();
-                var availablePackagesToInstall = await resolver.ResolveWithVersionOverrideAsync(resolverContext, project, DependencyBehavior.Highest,
-                    (project, conflict) => _fileSystemService.CreateDeleteme(conflict.PackageIdentity.Id, project.GetInstallPath(conflict.PackageIdentity)),
-                    cancellationToken);
+                // Step 5. Build install list using NuGet Resolver and select available resources.
+                List<SourcePackageDependencyInfo> availablePackagesToInstall;
+                if (allowMultipleVersions)
+                {
+                    availablePackagesToInstall = resolverContext.AvailablePackages.ToList();
+                }
+                else
+                {
+                    // Track packages which already installed and make sure only one version of package exists
+                    var resolver = new Resolver.PackageResolver();
+                    availablePackagesToInstall = await resolver.ResolveWithVersionOverrideAsync(resolverContext, project, DependencyBehavior.Highest,
+                        (project, conflict) => _fileSystemService.CreateDeleteme(conflict.PackageIdentity.Id, project.GetInstallPath(conflict.PackageIdentity)),
+                        cancellationToken);
+                }
 
                 // Step 6. Download everything except main package and extract all
                 availablePackagesToInstall.Remove(mainPackageInfo);