Paket 6.0.6 does not correctly install packages

[yaakov-h]

Description

Paket v6.0.6 seems to be sometimes unpacking packages one directory too high in the filesystem hierarchy, which results in build-time warnings from .NET.

I did not see this behaviour under any previous version of Paket up to and including v6.0.0-beta8.

Steps to Reproduce

I wish I knew, I can't get this to repro on demand.

The steps I took when this happened twice were to take an existing repo using Paket 5.x, update it to Paket 6.0.6, and add new net5.0 build targets (the repos did not previously target net5.0, only net472, netstandard2.0, and netstandard2.1).

The Paket groups have storage: none defined.

Expected behavior

Paket installs packages as done previously and as done by NuGet. There are no new build warnings in my project.

Actual behavior

Errors from MSBuild:

warning Undefined: The folder 'C:\Users\yaakov.smith\.nuget\packages\system.reflection.typeextensions\lib' contains an invalid version.
warning Undefined: The folder 'C:\Users\yaakov.smith\.nuget\packages\system.reflection.typeextensions\ref' contains an invalid version.
warning Undefined: The folder 'C:\Users\yaakov.smith\.nuget\packages\system.reflection.typeextensions\runtimes' contains an invalid version.

[forki]

@baronfel is #4033 related?

[yaakov-h]

That's quite possible. rc005 seems to be working as expected, and that was only merged into rc006.

[baronfel]

I suppose that's entirely possible, I'm not sure why the library would resolve the package in an incorrect way. @yaakov-h do you have a minimal sample project that reproduces the error?

[yaakov-h]

Got a repro project up at https://github.com/yaakov-h/paket4075

Run run-to-repro.cmd, then inspect any of the package folders under <path to repo>\nuget\<package name>:

[baronfel]

@yaakov-h thank you! I'll try to take a look soon.

[baronfel]

yeah that's definitely quite odd and I've reproduced it with your sample.

[baronfel]

I think I've found the reason for this, and it's entirely me being dumb and the nuget client APIs being utterly incomprehensible and very very overabstracted. It comes down to the difference in behavior/implementation of ExtractPackageAsync and InstallFromSourceAsync.

The former is what is currently in use in Paket, and it takes a path resolver that gives back old-style nuget paths. This is why we had a separate 'now move the extracted files to their proper versioned directory' step after this extraction. However, InstallFromSourceAsync takes a versioned path resolver and does all of the correct things by default, meaning we can remove our custom copying code for the extraction, as well as no longer leaving any extracted files in the package root.

MR coming up shortly.