Generating errors for duplicate files in publish output

[marcpopMSFT]

Generating errors for duplicate files in publish output

We added a new error (NETSDK1148) in cases where files from different source paths would be copied to the same file path in the publish output. This can happen when a project and its project references include a file with the same name that is included in the publish output.

dotnet/sdk#10850
dotnet/sdk#14020

Version introduced

6.0.100-preview1

Old behavior

Both files would be copied to the same destination. The second one would overwrite the first one, so which file "won" was mostly arbitrary.

In some cases, the build would fail, for example when trying to create a single-file app the bundler would fail with an ArgumentException:

C:\Program Files\dotnet\sdk\5.0.100-preview.5.20258.6\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Publish.targets(962,5): error MSB4018: The "GenerateBundle" task failed unexpectedly. [C:\repro\repro.csproj]
C:\Program Files\dotnet\sdk\5.0.100-preview.5.20258.6\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Publish.targets(962,5): error MSB4018: System.ArgumentException: Invalid input specification: Found multiple entries with the same BundleRelativePath [C:\repro\repro.csproj]
C:\Program Files\dotnet\sdk\5.0.100-preview.5.20258.6\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Publish.targets(962,5): error MSB4018: at Microsoft.NET.HostModel.Bundle.Bundler.GenerateBundle(IReadOnlyList`1 fileSpecs) [C:\repro\repro.csproj]

New behavior

We remove duplicate files copied to the publish folder if both the source and destination are the same. If there are any remaining duplicates, we generate a NETSDK1148 error, listing the files which are duplicated.

Reason for change

Duplicate files in the publish output were sometimes causing build breaks and in other situations causing unpredictable behavior.

Recommended action

Ideally, projects should be updated to avoid situations where multiple files with the same name will be copied to the publish output.

Additionally, the following property can be set to suppress the check for duplicate files:
<ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles>

Category

• ASP.NET Core
• C#
• Code analysis
• Core .NET libraries
• Cryptography
• Data
• Debugger
• Deployment
• Globalization
• Interop
• JIT
• LINQ
• Managed Extensibility Framework (MEF)
• MSBuild
• Networking
• Printing
• Security
• Serialization
• [ x] SDK
• Visual Basic
• Windows Forms
• Windows Presentation Foundation (WPF)
• XML, XSLT

Affected APIs

"Not detectable via API analysis"

Issue metadata

• Issue type: breaking-change

[dsplaisted]

@pranavkm @vijayrkn @javiercn @mkArtakMSFT Can you folks take a look at this write-up for the breaking change discussed here? dotnet/aspnetcore#29524

Are folks still likely to run into this with libman.json files? Should we exclude those from the globs, or include mention of that scenario in the write-up here?

[gewarren]

Ping for review of this breaking change issue @pranavkm @vijayrkn @javiercn @mkArtakMSFT.