Fix PublishSingleFile failure when GenerateDocumentationFile=true and CopyDocumentationFileToOutputDirectory=false

[Copilot]

When GenerateDocumentationFile=true and CopyDocumentationFileToOutputDirectory=false, the XML doc file is never written to the bin/ output directory. However, ComputeResolvedFilesToPublishList was unconditionally adding it to ResolvedFileToPublish via @(FinalDocFile) (which resolves to the bin/ path), causing GenerateBundle to throw FileNotFoundException during PublishSingleFile.

Changes

• Microsoft.NET.Publish.targets: Add '$(CopyDocumentationFileToOutputDirectory)' != 'false' to the condition guarding the XML doc file entry in ResolvedFileToPublish, mirroring how PDB publishing already gates on $(CopyOutputSymbolsToPublishDirectory):

<ResolvedFileToPublish Include="@(FinalDocFile)"
                        Condition="'$(PublishDocumentationFile)' == 'true' and
                                   '$(CopyDocumentationFileToOutputDirectory)' != 'false'">
  <RelativePath>@(FinalDocFile->'%(Filename)%(Extension)')</RelativePath>
  <CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>
</ResolvedFileToPublish>

• GivenThatWeWantToPublishASingleFileApp.cs: Add regression test It_succeeds_when_xml_docs_generated_but_not_copied_to_output covering the GenerateDocumentationFile=true + CopyDocumentationFileToOutputDirectory=false + PublishSingleFile=true combination.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>PublishSingleFile publish fails when XML docs are generated but not copied to the output directory</issue_title>
<issue_description>### Describe the bug
dotnet publish fails when GenerateDocumentationFile and PublishSingleFile are set to true while CopyDocumentationFileToOutputDirectory is set to false.

To Reproduce

1. Create a project with the following .csproj file:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <GenerateDocumentationFile>true</GenerateDocumentationFile>
    <CopyDocumentationFileToOutputDirectory>false</CopyDocumentationFileToOutputDirectory>
    <PublishSingleFile>true</PublishSingleFile>
  </PropertyGroup>

</Project>

2. Run dotnet publish

Restore complete (0.3s)
  PublishingBug net10.0 win-x64 failed with 1 error(s) (0.3s) → PublishingBug\bin\Release\net10.0\win-x64\PublishingBug.dll
    C:\Program Files\dotnet\sdk\10.0.100\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Publish.targets(1132,5): error MSB4018:
      The "GenerateBundle" task failed unexpectedly.
      System.IO.FileNotFoundException: Could not find file 'C:\Users\User\source\repos\PublishingBug\PublishingBug\bin\Release\net10.0\win-x64\PublishingBug.
      xml'.
      File name: 'C:\Users\User\source\repos\PublishingBug\PublishingBug\bin\Release\net10.0\win-x64\PublishingBug.xml'
         at Microsoft.Win32.SafeHandles.SafeFileHandle.CreateFile(String fullPath, FileMode mode, FileAccess access, FileShare share, FileOptions options)
         at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String fullPath, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 pr
      eallocationSize, Nullable`1 unixCreateMode)
         at System.IO.Strategies.OSFileStreamStrategy..ctor(String path, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preall
      ocationSize, Nullable`1 unixCreateMode)
         at System.IO.Strategies.FileStreamHelpers.ChooseStrategyCore(String path, FileMode mode, FileAccess access, FileShare share, FileOptions options, In
      t64 preallocationSize, Nullable`1 unixCreateMode)
         at System.IO.File.OpenRead(String path)
         at Microsoft.NET.HostModel.Bundle.Bundler.IsAssembly(String path, Boolean& isPE)
         at Microsoft.NET.HostModel.Bundle.Bundler.InferType(FileSpec fileSpec)
         at Microsoft.NET.HostModel.Bundle.Bundler.GetFilteredFileSpecs(IEnumerable`1 fileSpecs)
         at Microsoft.NET.HostModel.Bundle.Bundler.GenerateBundle(IReadOnlyList`1 fileSpecs)
         at Microsoft.NET.Build.Tasks.GenerateBundle.<>c__DisplayClass56_0.<ExecuteWithRetry>b__0()
         at Microsoft.NET.Build.Tasks.GenerateBundle.DoWithRetry(Action action)
         at Microsoft.NET.Build.Tasks.GenerateBundle.ExecuteWithRetry()
         at Microsoft.NET.Build.Tasks.GenerateBundle.ExecuteCore()
         at Microsoft.NET.Build.Tasks.TaskBase.Execute()
         at Microsoft.Build.BackEnd.TaskExecutionHost.Execute()
         at Microsoft.Build.BackEnd.TaskBuilder.ExecuteInstantiatedTask(TaskExecutionHost taskExecutionHost, TaskLoggingContext taskLoggingContext, TaskHost
      taskHost, ItemBucket bucket, TaskExecutionMode howToExecuteTask)

Further technical details

details of dotnet --info

.NET SDK: Version: 10.0.100 Commit: b0f34d51fc Workload version: 10.0.100-manifests.5fb86115 MSBuild version: 18.0.2+b0f34d51f

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19045
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\10.0.100\

.NET workloads installed:
There are no installed workloads to display.
Configured to use workload sets when installing new manifests.
No workload sets are installed. Run "dotnet workload restore" to install a workload set.

Host:
Version: 10.0.0
Architecture: x64
Commit: b0f34d51fc

.NET SDKs installed:
9.0.112 [C:\Program Files\dotnet\sdk]
10.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 9.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 10.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 9.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 10.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 9.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 10.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
DOTNET_CLI_UI_LANGUAGE [en-US]
DOTNET_GCHeapCo...

• Fixes PublishSingleFile publish fails when XML docs are generated but not copied to the output directory #52015

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Pull request overview

This PR fixes a FileNotFoundException that occurs during PublishSingleFile when GenerateDocumentationFile=true and CopyDocumentationFileToOutputDirectory=false. The issue was that the XML documentation file was being added to the publish list even though it was never copied to the output directory.

Changes:

• Added a condition check in Microsoft.NET.Publish.targets to prevent adding XML doc files to the publish list when CopyDocumentationFileToOutputDirectory=false
• Added a regression test to verify the fix works correctly with PublishSingleFile

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Publish.targets	Added CopyDocumentationFileToOutputDirectory != 'false' condition to prevent FileNotFoundException when XML docs are generated but not copied to output
test/Microsoft.NET.Publish.Tests/GivenThatWeWantToPublishASingleFileApp.cs	Added regression test verifying PublishSingleFile succeeds when GenerateDocumentationFile=true and CopyDocumentationFileToOutputDirectory=false