NuGet包下载目录异常：版本号与包ID混存问题求助

使用程序化代码下载NuGet包时，包已成功添加至MachineWideConfigDirectory，但实际存储路径为.nuget/packages/Microsoft.Extensions.Logging.6.0.0，而非预期的.nuget/packages/microsoft.extensions.logging/6.0.0。

原始代码与配置 #

程序化下载包的代码 #

var settings = Settings.LoadDefaultSettings(string.Empty, null, new MachineWideSettings());
var packageSourceProvider = new PackageSourceProvider(settings);
var sourceRepositoryProvider = new SourceRepositoryProvider(packageSourceProvider, Providers);
var framework = NuGetFramework.Parse(Assembly.GetEntryAssembly()!.GetCustomAttribute<TargetFrameworkAttribute>()!.FrameworkName!);

var package = await this.GetPackageAsync(this.PackageId, this.PackageVersion, this.IncludePreRelease, false, cancellationToken).ConfigureAwait(false) ?? throw new ArgumentNullException($"Failed to find the specified package with id '{this.PackageId}' and version '{this.PackageVersion}'");
var project = new PluginNugetProject(this.PackagesDirectory.FullName, this.PluginDirectory.FullName, package.Identity, framework);
var packageManager = new NuGetPackageManager(sourceRepositoryProvider, settings, this.PackagesDirectory.FullName) { PackagesFolderNuGetProject = project };
var clientPolicyContext = ClientPolicyContext.GetClientPolicy(settings, this.NugetLogger);
var projectContext = new PluginNugetProjectContext(this.LoggerFactory) { PackageExtractionContext = new PackageExtractionContext(PackageSaveMode.Defaultv3, PackageExtractionBehavior.XmlDocFileSaveMode, clientPolicyContext, this.NugetLogger) };
var resolutionContext = new ResolutionContext(DependencyBehavior.Lowest, true, false, VersionConstraints.None);
var downloadContext = new PackageDownloadContext(resolutionContext.SourceCacheContext, this.PackagesDirectory.FullName, resolutionContext.SourceCacheContext.DirectDownload);

await packageManager.InstallPackageAsync(project, package.Identity, resolutionContext, projectContext, downloadContext, package.SourceRepository, new List<SourceRepository>(), cancellationToken).ConfigureAwait(false);
await project.PostProcessAsync(projectContext, cancellationToken).ConfigureAwait(false);
await project.PreProcessAsync(projectContext, cancellationToken).ConfigureAwait(false);
await packageManager.RestorePackageAsync(package.Identity, projectContext, downloadContext, new[] { package.SourceRepository }, cancellationToken).ConfigureAwait(false);

MachineWideSettings实现 #

class MachineWideSettings
    : IMachineWideSettings
{

    public ISettings Settings => NuGet.Configuration.Settings.LoadMachineWideSettings(NuGetEnvironment.GetFolderPath(NuGetFolderPath.MachineWideConfigDirectory));

}

nuget.config配置 #

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <packageSources>
    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" protocolVersion="3" />
    <add key="Microsoft Visual Studio Offline Packages" value="C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\" />
  </packageSources>
</configuration>

修正方案 #

核心原因 #

问题出在自定义的PluginNugetProject替换了NuGetPackageManager默认的PackagesFolderNuGetProject，导致NuGet v3标准的小写ID+版本子目录存储逻辑被覆盖。默认的PackagesFolderNuGetProject会自动处理包ID的小写转换和路径分层，而自定义项目未实现该逻辑。

具体修正步骤 #

1. 移除自定义项目替换逻辑
   不要将packageManager.PackagesFolderNuGetProject设置为自定义的PluginNugetProject，保留NuGet默认的实现。

2. 调整安装目标项目
   调用InstallPackageAsync时，传入默认的packageManager.PackagesFolderNuGetProject作为安装目标，确保路径遵循v3规范。

3. 按需添加自定义目录处理
   如果需要将包文件同步到插件目录，在包安装完成后，基于标准存储路径手动复制文件到目标目录。

修改后的关键代码 #

var settings = Settings.LoadDefaultSettings(string.Empty, null, new MachineWideSettings());
var packageSourceProvider = new PackageSourceProvider(settings);
var sourceRepositoryProvider = new SourceRepositoryProvider(packageSourceProvider, Providers);
var framework = NuGetFramework.Parse(Assembly.GetEntryAssembly()!.GetCustomAttribute<TargetFrameworkAttribute>()!.FrameworkName!);

var package = await this.GetPackageAsync(this.PackageId, this.PackageVersion, this.IncludePreRelease, false, cancellationToken).ConfigureAwait(false) 
              ?? throw new ArgumentNullException($"Failed to find the specified package with id '{this.PackageId}' and version '{this.PackageVersion}'");

// 保留默认的PackagesFolderNuGetProject，不替换为自定义项目
var packageManager = new NuGetPackageManager(sourceRepositoryProvider, settings, this.PackagesDirectory.FullName);
var clientPolicyContext = ClientPolicyContext.GetClientPolicy(settings, this.NugetLogger);
var projectContext = new PluginNugetProjectContext(this.LoggerFactory) { 
    PackageExtractionContext = new PackageExtractionContext(PackageSaveMode.Defaultv3, PackageExtractionBehavior.XmlDocFileSaveMode, clientPolicyContext, this.NugetLogger) 
};
var resolutionContext = new ResolutionContext(DependencyBehavior.Lowest, true, false, VersionConstraints.None);
var downloadContext = new PackageDownloadContext(resolutionContext.SourceCacheContext, this.PackagesDirectory.FullName, resolutionContext.SourceCacheContext.DirectDownload);

// 使用默认项目执行安装，确保路径符合v3规范
await packageManager.InstallPackageAsync(packageManager.PackagesFolderNuGetProject, package.Identity, resolutionContext, projectContext, downloadContext, package.SourceRepository, new List<SourceRepository>(), cancellationToken).ConfigureAwait(false);

// 自定义逻辑：将已安装的包内容复制到插件目录（示例）
var standardPackagePath = Path.Combine(
    this.PackagesDirectory.FullName,
    package.Identity.Id.ToLowerInvariant(),
    package.Identity.Version.ToString()
);
// 实现CopyDirectory方法完成目录复制
CopyDirectory(standardPackagePath, this.PluginDirectory.FullName);

// 按需保留或调整自定义的Post/PreProcess逻辑
// await project.PostProcessAsync(projectContext, cancellationToken).ConfigureAwait(false);
// await project.PreProcessAsync(projectContext, cancellationToken).ConfigureAwait(false);
await packageManager.RestorePackageAsync(package.Identity, projectContext, downloadContext, new[] { package.SourceRepository }, cancellationToken).ConfigureAwait(false);

补充说明 #

• NuGet v3存储规范要求包ID必须小写，版本作为子目录存在于ID目录下，默认PackagesFolderNuGetProject内部已封装该逻辑。
• 若PluginNugetProject包含特定业务逻辑，建议仅用它处理后续的自定义流程，而非替换默认的包存储项目。

内容的提问来源于stack exchange，提问作者Charles d'Avernas