Azure DevOps保留期PATCH请求失败问题排查求助

已成功实现Azure DevOps多阶段构建与发布流水线的变量共享，但调用PATCH API更新构建保留租期时失败，错误提示保留租期更新内容为null，请问这是Bug吗？我的请求格式是否正确？

执行的PowerShell任务代码 #

- task: PowerShell@2
  condition: and(succeeded(), not(canceled()))
  name: RetainOnSuccess
  displayName: Retain on Success
  inputs:
    failOnStderr: true
    targetType: 'inline'
    script: |
      $contentType = "application/json";
      $headers = @{ Authorization = 'Bearer $(System.AccessToken)' };
      $rawRequest = @{ daysValid = 100; protectPipeline = false; };
      $request = ConvertTo-Json @($rawRequest);
      $uri = "https://dev.azure.com/testing-ci/$(System.TeamProject)/_apis/build/retention/leases/$(myVarfromStage)?api-version=7.1-preview.2";
      Invoke-RestMethod -uri $uri -method PATCH -Headers $headers -ContentType $contentType -Body $request;

DevOps返回的错误信息 #

"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -NoLogo -NoProfile -NonInteractive -ExecutionPolicy Unrestricted -Command ". 'D:\a\_temp\6ee1c3fd-e406-417e-bf9f-d860a21d1647.ps1'"
##[error]Invoke-RestMethod : {"$id":"1","innerException":null,"message":"The retention lease update is 
null.","typeName":"Microsoft.TeamFoundation.Build.WebApi.RetentionLeaseUpdateIsNull, 
Microsoft.TeamFoundation.Build2.WebApi","typeKey":"RetentionLeaseUpdateIsNull","errorCode":0,"eventId":3000}
At D:\a\_temp\6ee1c3fd-e406-417e-bf9f-d860a21d1647.ps1:8 char:1
+ Invoke-RestMethod -uri $uri -method PATCH -Headers $headers -ContentT ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (System.Net.HttpWebRequest:HttpWebRequest) [Invoke-RestMethod], WebExc 
   eption
    + FullyQualifiedErrorId : WebCmdletWebResponseException,Microsoft.PowerShell.Commands.InvokeRestMethodCommand
##[error]PowerShell exited with code '1'.

问题分析与解决方案 #

这不是Bug，是请求体格式不符合API要求导致的。

错误提示The retention lease update is null说明API无法识别传入的请求内容，问题出在代码中将请求对象包装成了数组：

$request = ConvertTo-Json @($rawRequest);

Azure DevOps的Retention Lease PATCH API期望接收单个RetentionLeaseUpdate对象，而非数组。只需去掉数组包装，直接将单个对象转为JSON即可：

修正后的代码片段：

$rawRequest = @{ daysValid = 100; protectPipeline = false; };
$request = ConvertTo-Json $rawRequest; # 移除@()数组包装

修改后重新执行任务，PATCH请求就能正确识别更新内容，解决该错误。

内容的提问来源于stack exchange，提问作者John