'dotnet lambda publish-layer' fails in .NET 6 with ‘--enable-package-optimization true’

Describe the bug

When trying to publish a .NET 6 layer, if you try to enable package optimizations, you will get an exception complaining about crossgen not existing in the tools directory of the .NET 6 SDK. It seems crossgen is no longer included with .NET 6 tools. And it sounds like this is by design according to this issue: https://github.com/dotnet/sdk/issues/24752

Example command that throws the error: dotnet lambda publish-layer dotnetsixlayer --layer-type runtime-package-store --s3-bucket my-layer-store-bucket --region us-east-1 --package-manifest ./layer-test-manifest.csproj --enable-package-optimization true --framework net6

Either removing the --enable-package-optimization true or downgrading to .NET 5 fixes the problem.

Expected Behavior

Publishes the layer to the store

Current Behavior

Amazon Lambda Tools for .NET Core applications (5.3.0)
Project Home: https://github.com/aws/aws-extensions-for-dotnet-cli, https://github.com/aws/aws-lambda-dotnet
	
Warning: Package optimization has been enabled. Be sure to run this on an Amazon Linux environment or the optimization might not be compatbile with the Lambda runtime.
Converted ASP.NET Core project file to temporary package manifest file.
... invoking 'dotnet store' for manifest /tmp/tmpzG6rga.tmp into output directory /tmp/dotnetsixlayer-637849539422701007/dotnetcore/store
... store: Microsoft (R) Build Engine version 17.1.0+ae57d105c for .NET
... store: Copyright (C) Microsoft Corporation. All rights reserved.
... store:   Determining projects to restore...
... store:   Restored /tmp/tmpzG6rga.tmp (in 377 ms).
... store: /usr/share/dotnet/sdk/6.0.201/Sdks/Microsoft.NET.Sdk/targets/Microsoft.NET.CrossGen.targets(82,5): error NETSDK1016: Unable to find resolved path for '/home/ec2-user/.nuget/packages/microsoft.netcore.app.runtime.linux-x64/6.0.3/runtimes/linux-x64/native/../../../tools/crossgen'. [/tmp/tmpzG6rga.tmp]
Error executing the 'dotnet store' command

Reproduction Steps

On an AL2 VM, create a file layer-test-manifest.csproj with a NuGet reference in it, then run this command: dotnet lambda publish-layer dotnetsixlayer --layer-type runtime-package-store --s3-bucket my-layer-store-bucket --region us-east-1 --package-manifest ./layer-test-manifest.csproj --enable-package-optimization true --framework net6

Possible Solution

This open issue mentions using FrameworkReferences

Additional Information/Context

No response

Targeted .NET platform

.NET 6

CLI extension version

Package Id Version Commands

amazon.lambda.testtool-3.1 0.12.1 dotnet-lambda-test-tool-3.1 amazon.lambda.testtool-5.0 0.12.0 dotnet-lambda-test-tool-5.0 amazon.lambda.testtool-6.0 0.12.1 dotnet-lambda-test-tool-6.0 amazon.lambda.tools 5.3.0 dotnet-lambda nbgv 3.4.255 nbgv

Environment details (OS name and version, etc.)

Windows 10, Amazon Linux 2

[Beau-Gosse-dev]

@ashishdhingra it looks like Microsoft is removing support for dotnet store all together. Do we have a plan to keep functionality with .NET Lambda Layers some other way?

[controdave]

@controdave There are 2 workarounds for publishing a layer still, do either of these help for now?

Either removing the --enable-package-optimization true or downgrading to .NET 5 fixes the problem.

Awe shucks, will there be a performance knock at all with remove package optimization? Thank you sir!